Mapping emissions to the OES is very challenging, and the process is complicated.  EPA appears to have done an admirable job using the available information.  A broader description of what is and is not in TRI would be helpful.  A crosswalk in Appendix C was very helpful in understanding how the TRI data would map to OES.  Significant elements of professional judgement appear to be involved, which may diminish the objectivity and credibility of this method.  More text is required to explain these decisions.
                  Much of the execution of the methodology is in tables without text descriptions.  While tables are helpful, it would be better to have more supplementing text.  EPA should consider demonstrating the validity of this method by selecting an example where conditions of use are known and then applying the methodology to see if it reproduces the result.  It is not clear why EPA did not leverage the National Emissions Inventory data, which contained additional relevant data on stack parameters.  One limitation that is noted is that TRI would have more recent data.
                  While that is true, it's unclear that recent data outweighs the use of the larger NEI data set.  So, the methodologies do build largely on the TRI datasets from 2019 and other available data for previous years, but the use of single years versus multiple years needs to be specified as to how that is selected and how the decisions are made for which of the multiple years are used.  One should be aware that emissions data may vary or fluctuate dramatically over years because emission and assets are proportional to total tonnage of chemicals used in a given year.
                  Discussants (audio skip) were assessing when TRI data are not available for multiple years of TRI.  Justification for higher priority given to modeling results compared to the existence of literature sources used in published risk evaluations -- modeling results are not unconditionally superior to literature-based report estimates.  The 500 pound threshold for reporting should be explicitly stated as the default value for small users in the Agency's general and detailed descriptions of the approach.
                  Discussants found that AERMOD was a reasonable selection at this level of sophistication.  Within Figure 2.1, the emission source icon looks like a cooling tower, which is probably not representative of the sources of toxics.  Actual data are needed from industries that are generating or using the chemicals in question.  That refers to information on page 24.  In Figure 2.3 the approach used here must be to obtain data, not to implement model-based results that are based on unexplained or non-existent data.
                  If data are unavailable, users should provide them under strict quality control.  It was quite disappointing today to hear that many commentors representing trade groups are criticizing the EPA for an approach that does not have data.  And these data are ones that the trade associations could have easily provided in the interim between the time that this process began and today.  It is not clear how the Agency can model environmental concentrations without input data.
                  Any such exercise will require the use of adjustment factors or uncertainty factors to avoid a false negative result.  The Agency should describe which safety factors are used.  And if there are no safety factors, then the Agency should provide an explanation for why there are not.  The Trinity Consultant's report was rather lengthy, but it appeared to be a survey of users and not a comprehensive inventory of emission from all users.  I could be mistaken there, but that was my take on that.
                  Also, the methodology for screening level ambient air pollution has a static distance of 10,000 meters from the point source.  And the comment was made that many air pollutants would have an isotropic plume of exposure depending on the prevailing winds and not all contaminants have similar environmental transport characteristics.  Thus, 10,000 meters may not be as protective for some compounds as for others.  The 10,000 meter distance is arbitrary, but it does seem to protect most contaminants.  But there could be some that could be improved by a larger distance.
                  Deciding which emission types are most hazardous is essential for outcome of fenceline risk evaluations.  Modeling fugitive and stack emissions and selecting the worst-case would seem to be the most conservative approach.  The extent to which an emission type is hazardous would be location and population dependent.  A need for the recommended type of placement would be to have actual emission points located along with stack dimensions and operation conditions.
                  Mapping facilities to OES from internet searches does not follow typical standards of reproducibility, and it would be preferable to have each company provide operational facility locations, not administrative locations.  The open top degasser inclusion is a good aspect of the approach.  However, release durations and patterns are needed.  And, without data to this effect, worst-case release or high centiles of worse-case releases should always be included.
                  EPA's integrated indoor/outdoor air calculator does predict concentrations at 100 meters and beyond.  But it's inadequate for measuring estimates nearer to the sources.  And this is important for fugitive emissions.  Exposure scenarios were well-described and well-depicted in Figure 2.5 with a few exceptions.  Does West Coast imply mountainous or hilly terrain?  Maybe flat terrain?  How are building densities and heights considered?  And are the Xs in Figure 2.5 the only areas model, or are all 16 points at 2.5 degree spacing modeled at all distances?
                  The different kinds of landscapes could vasty influence chemical transports.  Including high centile chemical atmospheric release values, on page 29, would be preferable, maybe something like a 90th or 95th percentile as well just to make sure that that distribution is somewhat well-understood.  This would ensure that the max is not too high and is not unreasonable.  On page 30, the threshold of ten to the minus six for cancer risk is appropriate.  It does seem that some tables later in the assessment use less protective thresholds.  And the more protective thresholds are the ones that are needed.
                  Also, citations for this cancer benchmark should be provided on lines 595 through 601.  The ability to model multiple atmospheric scenarios is good.  If empirical data are not available, adjustment factors or uncertainty factors should be needed.  Appendix D has release heights that may not represent actual release scenarios.  For example, ten meter heights may not be appropriate for a dry cleaning operation or small machine operation.  Worst-case scenarios may, in fact, be different depending on the topography, building characteristics, or densities, as well as population distributions.
                  The discussants were interested whether land use was considered and land use changes.  There should be ways to operationalize land uses and their considerations using visual analyses.  The visual examination was a good aspect of the assessment.  Maximum emission values were modeled now at only 95th and higher centiles.  Detects need to be harmonized, and inclusion of both maximum and high centile values would be useful.  The modeling approach on page 37 was good and had informative graphics there in Figure 2.7.  Guys, I'm about halfway through.
                  The description of the approach to modeled area sources is confusing in Figure 2.8.  And we've talked about whether these Xs are all the receptor model locations or if there are more.  The IECCU model, wall losses are not included in this model.  This may be an aspect needed for higher tier refinement.  Not including wall losses may be conservative, but that should be explicitly stated in the document.  So, as we move on to drinking water, drinking water exposures are estimated for public water supplies six-year EPA data, but they're only available for some contaminants.
                  Also, private wells are not considered.  This is a concern since private well users may be exposed to higher concentrations of contaminants removed by certain public health drinking water processes.  And fenceline communities may not have the financial resources to expect individual household level remediation of their water.  The estimation procedures for incidental oral exposures from swimming and incidental dermal exposures from swimming were clearly articulated.
                  Data are needed in these assessments, however.  These data should be gathered by users.  I've talked about uncertainty factors already.  The formulas for risk characterization for non-cancer risks, i.e. benchmarks margin of error, and for cancer risk are presented clearly.  These elements are calculated similarly for other EPA projects.  So, in Line 573, there was a question as to why not use the ADJ_U for 2011 to 2015 data.  The reason provided is unclear and without a citation.
                  On page 56, it's unclear how the census data related to the number of facilities releasing specific chemicals.  That should be clarified.  Distances of 5 to 60 meters for atmospheric exposures are good inclusions for this approach, but it doesn't match the distances in the IIOAC, as EPA outlined.  Inhalational risks really do need to be modeled at these distances, something like 5, 10, 30, and 60 meters, to capture the shape of the risk profile near the 10 meter fugitive emission threshold and then out to the 100 meter IIOAC minimum distance.
                  EPA should provide an indication of exactly how close is close enough to pass the prescreen for exposure concentration.  It may be better to modify the IIOAC or develop a supplement rather than to try to predict concentrations closer than 100 meters through the processes that EPA is currently using.  Concentrations at ground level from stack emissions may tend to peak near 100 meters, but that estimate will surely depend on stack height, effluent velocity, and wind.
                  On page 58, even with a peer-reviewed model, there are many uncertainties and specific evaluations using observations -- for instance, the NATTS network for toxic chemicals -- would improve confidence.  Conservative plume characteristics are appropriate at this level, and should refiners be necessary, operators can provide empirical data related to specific facilities or accept these conservative assumptions.  Having only data for methylene chloride in drinking water is unacceptable.  These chemicals have been under review for several years now, and these data are easily obtainable by initiating or expanding monitoring programs.
                  The discussants noted that water exposure release was ruled out for 1-BP based on physical chemical properties and release data.  Please better define how and what properties are used to evaluate potential risk pathways and the exclusion mentioned above.  For example, what are the cutoff values for Henry's Law of Constants that would be used to eliminate a compound from consideration?  Could or should any environmental compartments be eliminated in a fashion similar for other chemicals or future chemical considerations?
                  There is significant uncertainty related to emissions to air and how much of that will be partitioned into water.  This was pointed out in previous SACC meetings, and a figure will be provided in the written comments.  This is the reason that monitoring data are essential.  Based on volatilization assumptions of wastewater treatment plants, airborne releases from these facilities would perhaps serve as sources of toxicants of concern in water.  This is important for compounds like 1-BP that degrade slowly in air and can be transported long distances and partitioned back into water.
                  On page 63, the cancer slope provided in that table should be explained a little bit.  What is the point of departure?  Is it zero with a slope of four times ten to the minus three per part per million?  In Table 3-38, the lower bound of the OES for chemical processing, excluding formulations, should not be 0.91 kilograms per site per year.  This is due to an apparent misuse/mismatch within one of the files, "SF_FLA_Water Path Exposure Data for NMP."
                  Also, 59 sites reported to be releasing NMP, on page 63, but how many users were there?  Is this 59 of a small number or 59 of a very large number?  It's important to know what fraction of users are providing data.  Additionally it would be important to know the fraction of the chemical use that is reported that would go towards mass balance.   Also, on page 67, data are needed to feed this model.  And the survey from the Trinity Consultant report may not be comprehensive enough to provide that.
                  On page 69, the statement that Appendix B includes model parameters and output is misleading.  Appendix B simply includes a list of files that are then linked in the document.  So the format's not really very helpful there.  Also on page 69, the estimated data needed to be comprised of submitted use and release data from users or trade associations.  To improve the scientific defensibility of this approach, data should be required as part of review of these chemicals under TSCA.
                  To assist the reviewers and better facilitate use of screening approaches by non-EPA personnel the panel suggests adding more comments on specific cells to the Excel models or data sheets.  For example, the fugitive basis description column and the environmental releases to environmental ambient area for 1-BP list best engineering judgement.  What does that indicate?  Please ensure that definitions are provided for abbreviations used as column headings for input tables in the supplemental files.
                  Risk data in Table 3.9 predict risk for the 10th and 50th centile emissions in at least one scenario for each OES.  This should be stated explicitly so as not to leave the impression that only high centile releases generate risks.  On page 90, Table 3-12, the cancer risk of 1 in 10,000 is used, not 1 in a million.  The more protective value is needed.  Also, the conversion of gaseous concentrations from milligrams per cubic meter to parts per million assumes ideal gas at standard temperature and pressure.
                  And this may be sensitive to results of to -- excuse me, oh, my goodness.  My cursor just got hit.  Hold on, guys.  I just hit about a hundred carriage returns.  So we need to make sure that we don't have a calculation error at higher altitudes.  Pardon me for that.  I hit -- I did.  I hit about a hundred carriage returns and had to find my place.  Okay.
                  And, more broadly, from my perspective at least, the unit of part per million bpm is problematic.  I would say that microgram per cubic meter is preferable.  But if we're gonna use bpm, you should be clear as to whether that unit is mass per mass, volume per volume, or mass per volume.  Just be explicit with that.  Okay.  On page 91, the statement regarding under- or over-prediction of risk from varying exposure durations is misleading.
                  There are likely data to suggest whether a 1.5 hour exposure duration under or over predicts carcinogenicity of chronic exposure to chlorinated or volatile compounds.  This should be evaluated in the next revision.  Also, it would be useful to include more info on the six-year review and the EFAST data since these concentrations drive the rest of the aquatic analysis.  Omitting estuaries, bays, lakes should probably be more clearly justified in the introductory materials.  There's a question as to whether ambient water samples were collected near any of the facilities that were discharging methylene chloride.
                  If the monitoring data were not near any methylene chloride facilities, then the water monitoring are at best meaningless and, at worst, misleading.  So monitoring data near facilities discharging these chemicals are what's needed for these type of assessments.  The data in Table 319 need to be revised to include a better approach to handle the wide range of limits of detection.  We came across this in previous SACCs, and there's such wide range of limits of detection that some very serious treatment needs to be done with this.
                  Note that the 10th and 50th centile releases also demonstrate risk exceedances for several scenarios, on page 125.  And that point should be explicitly stated earlier, much earlier in the document.  Data in Table 326 are difficult to reconcile with spreadsheets for the file "Raw_Data-all_cals" and "Summary_Risk_Found" because these spreadsheets have different sorts, and so the data are not in the same columns or the same -- or perhaps the same rows.  So that makes reconciling difficult, not impossible, but more difficult.
                  On page 143, knowing how much of a reported NMP is released is important.  But of equal, if not more, importance is knowledge about unreported amount of NMP.  What fraction is unreported?  Does an 87 percent release of reported amounts represent 80 or more percent of the total releases or less than 0.8 percent?  We simply don't know.  This same comment goes for all chemicals and all aspects of TSCA risk determinations.
                  It would be important to know how NMP concentrations in water compare to possible partitioning from air, as was raised in previous SACC meetings.  The highest annual outdoor air concentrations on page 190 are predicted values and should be identified as such.  And this is a general comment for all modeled and predicted estimates.  So there could be some additional clarity in some of the mitigation options.  One discussant mentioned that risk conclusions should not be yes or no but rather maybe or no.  And that's because this is a screening level analysis, and a yes gets you to another level of screening perhaps.
                  Outcome 5 suggests refinements will be considered in some cases when a COU exceeds risk levels.  Clarity is needed here to determine what to do if refinements are not possible.  An action may not be appropriate if a regulated community were to provide data to fill data gaps.  The recourse afforded users should be included in the proposed use.  Excuse me, in the proposed rule.  Let me read that again.  The recourse afforded users should be included in the proposed rule.  Guys, I'm almost done.  I'm down to uncertainties now.
                  The approach has large uncertainties, many of which are noted in Section 2.4.  For most areas with uncertainty -- for example, in incorporating incomplete emission data -- EPA takes a conservative approach but not always the most conservative approach to quantifying risk.  But it's often unclear how reliable even the conservative assumptions are.  It may be useful to implement a formal uncertainty analysis to explore how variability in the inputs will introduce variability into the results.
                  Discussants suggest including aggregate emissions, emission distributions through the year stack and fugitive source heights, temperatures and velocities, as well as meteorology at different times of the year.  Large uncertainties also exist when using predictive models that use results from other predictive models.  For example, estimated 1-BP releases from particular processes were used as input into other models used to estimate fenceline air concentrations.  How did these uncertainties compound themselves?
                  Emission estimate uncertainties should be described, and the uncertainty and emission estimates and mapping to OES are likely to be large.  But there's no attempt to quantify that.  There are underlying uncertainties in all emission estimates, some of which may be large.  EPA might consult the academic work of Dr. Chris Fry, the current ORD administrator.  Substantial things are missed without a specific -- let me read that again.  Substantial things are missed without a site-specific analysis which goes to whether the methodology is sufficient to act on alone without further refinement.
                  Aspects would be terrain, nearby buildings, specific information on emission velocity and modeling of separate release points.  There may be other factors that are not listed here.  More information on the availability of these screening tools to predict observed toxic concentrations and sensitivities to output would be very valuable to the interpretation of EPA's screening tool.  Given the uncertainties, this approach may not -- this approach is not appropriate for a full risk assessment and should be exclusively for screening.  As many of the public comments suggest, it's unclear the amount of information added by the ambient prescreening methodology.
                  The IIAOC, which likely produces results with greater uncertainty than the full AERMOD runs, may underestimate risk from certain CES, which would exclude them from the final analysis.  That would not be a good outcome.  It seems resources would be better spent streamlining the process for running the full AERMOD module for all of the CES.  Step 3 of the environmental air release section makes many assumptions with already uncertain annual emission totals.  It would be helpful to present more information on the sensitivity of these results on the assumptions.
                  Finally, a couple of general comments.  There are a few typos and missing references in the text.  Those will be included in our final response.  And there were places were rounding numbers in tables could potentially cause miscalculations if rounded figures were used directly in calculations.  With that, chairman, I will give you the mic back, gladly.
                  DR. DANIEL SCHLENK:  Thank you, George.  Appreciate that synopsis.  Let me go down the list here with associates to see if there's any further additions or discussant.  Dr. Doucette?
                  DR. WILLIAM DOUCETTE:  Thanks, Dan.  I think -- I hope George covered everything in that long-winded summary.  I just wanted to bring up two items that I felt were important and may not have been clearly presented.  I read this document, and I thought a more fundamental question might be is the proposed screening level approach truly useful, given the limitations in the release estimates and the lack of corroborating monitoring data?
                  So, I mean, from a fundamental point of view -- and I think this has been brought up in the public comments too.  And I know EPA's stuck between a rock and a hard place in doing this, but it's just a consideration.  Are we spending a lot of time generating or looking at these screening models, and it really doesn't improve our estimate of risk?  There might be some -- and I know there is'-- some fenceline monitoring programs for refineries that we might be able to use -- or could be used potentially to help validate or at least evaluate how accurate this screening technique is.
                  And, then, the other comment that I wanted to make too was how important it is to consider individual chemicals and look at how they are used and what their most likely route of human exposure would be, for example, dry cleaning solvents, 1-BP included.  But we're going to run across TCE and PCE.  The most likely source of human exposure is probably vapor intrusion from groundwater contamination.  And that was also brought up by several of the public comments.
                  And I think that's critical to, and maybe we can eliminate some of the pathways to look at if we look at the ones that are most important and focus our resources there, if we don't have monitoring data.  The related point I want to make to that is related to co-contaminants.  I've probably have been on dozens of groundwater contaminated sites and measured indoor air contamination related to vapor intrusion.  And if I'm looking at a TCE-contaminated site where that is the main solvent, typically we find another 20 compounds -- 20 related solvents within our analysis.
                  So it's that whole idea of co-contaminants that I realize is hard to get a grasp on, but that might be dealt with with expanding the uncertainty factors in the toxicological assessments.  And, then, finally -- and I think this is the appropriate time to bring this out -- I keep thinking that without good input data it's hard to have good output data.  And maybe the way would be to turn this around and use the model in a different way.
                  Under what circumstances, what meteorological conditions, what stack height, what emissions would give a concentration that would be risk?  So, in other words, turn the model around instead of trying to predict a fenceline concentration that we can't really predict very accurately.  Turn it around and what scenarios would be there that would result in a fenceline concentration that would likely be risk?  And that might be a way to start focusing on facilities where we could actually get monitoring data.  So I don't know if I was able to articulate that very well, but those are some of the comments that -- the more general comments that I had.
                  DR. DANIEL SCHLENK:  Okay.  Thanks, Bill.  Dr. Henneman.
                  DR. LUCAS HENNEMAN:  Yeah, I think George did a really good job capturing my comments.  I guess my primary comment is just to encourage EPA to really look at the uncertainties and the sensitivity of the model to these uncertainties and really give us a picture of, okay, is the information coming out of this screening approach useful for the things that we're trying to screen for?  And other than that, everything was captured, so thanks.
                  DR. DANIEL SCHLENK:  Thank you.  Dr. Li.
                  DR. LI LI:  Oh, yes.  I think George has done a very great job in capturing everything, including my responses.  So I just want to bring another point to everybody's attention, which is about the property of the chemical because I just realized that all the three case chemicals in this report just are very hydrophilic and volatile chemicals.  So, I'm not sure whether EPA just wanted this document designed specifically for these chemicals, the hydrophilic and volatile chemicals or EPA wants it to be a generic practical guideline for other chemicals in TSCA, for example, hydrophobic or minimal volatile organic chemicals, because this is something I think super important in terms of exposure pathway.
                  So, we just did a comprehensive review, which shows bio-cumulation of a chemical is not likely happen for chemicals that are very hydrophilic, very volatile, or highly unstable.  So this is of course the case for three case studies in this report, but I'm not sure if this is also the case for other chemicals if you want to include other chemicals in the future -- for example, if you want to do the assessment for dioxanes, for mercury, for chemicals that are highly hydrophobic, minimally volatile, or highly persistent, or PBT chemicals.
                  So maybe the first step to screen the property of the chemical and then determine which approach would be best suited for chemicals with certain properties, it would be better.  Yeah, that's my point.
                  DR. DANIEL SCHLENK:  Okay.  Thank you.
                  DR. LI LI:  Yeah, thank you.
                  DR. DANIEL SCHLENK:  Dr. Reiss?
                  DR. RICK REISS:  Yes, thank you.  I think George did a great job of summarizing a lot of information from all the discussants.  A few things I wanted to comment on, expand on a little bit.  The idea of fenceline monitoring is an interesting one.  I don't know if a dataset is out there that would be helpful, but, I mean, I think a lot of us were left wondering -- the approach wasn't really validating.  You're left wondering whether or not it's really screening things out, one, or whether it's underestimating or vastly overestimating to the point where it's not useful.
                  So, I mean, if there's any monitoring data out there that could be used for validation purposes, I think that would be really useful.  But I do acknowledge -- I mean, I've been involved in a number of fenceline monitoring initiatives, and those programs are very challenging to design, and very expensive.  So I'm not sure if that's going to be possible.  The other thing I wanted to do is comment a bit on the mitigation.  There is this implication that you could act on this alone -- I mean, this screening level analysis alone, if I read that correctly.
                  I mean, in all EPA kind of guidance documents you generally hear of screening level analysis.  The next step would be refinement, not a proposed rule.  So I'm left a little confused as to how this is different, especially because there's just -- the EPA has an enormously challenging problem here to model all these different facilities with so many data gaps.  And I know you're trying to develop a process where you're inputting conservative assumptions on top of conservative assumptions to make sure you're not underestimating.
                  But there's some very large -- I mean, Mr. Baker pointed out that you're using this 10 meter stack height.  The stack height can be quite a bit larger in many facilities and especially for high emitters.  And that could have orders of magnitude difference in concentration.  So that's just one example where you could be potentially significantly overestimating.
                  So, I mean, if you're going to propose acting on this screening level analysis, again, I don't think it's as consistent with the general risk assessment paradigm from EPA.  But I think you would have to be -- want to be more explicit about what you think the criteria would be that you would act versus not act -- act versus not go to a more refined risk assessment first.  So those are the comments I wanted to add.  Thank you.
                  DR. DANIEL SCHLENK:  Thank you.  Okay.  Let's open it up to the rest of the Committee.  First on the list, I've got Dr. Johnson.
                  DR. MARK JOHNSON:  Okay.  Thanks, Dan.  Yeah, just some quick ones.  First of all, this one comment alludes to something I kind of discussed earlier is I would suggest they make it explicit that these criteria are based on exposures to surface water, right?  That could potentially be used -- or would be used by drinking water facilities from municipal treatment facilities to provide drinking water.  So that's the drinking water pathway.
                  And maybe a conceptual site model would help describe that process.  We're not talking about groundwater here.  We could.  Maybe other chemicals would be more appropriate to do so, but for these two, we're talking about surface water releases that could wind up to drinking water through municipal treatment facilities.  The other comment I have here is regarding the use of TRI data that are yearly estimates of mass.
                  And maybe others have alluded to this as well, but I'm wondering about peaks and valleys, about spikes and how spikes are considered.  Maybe that's something that we can just discuss in terms of uncertainty, but you may want to discuss that in terms of how that may influence any unreasonable determination of risk.  And that's all I had.
                  DR. DANIEL SCHLENK:  Okay.  Thanks.  Bill, if you don't mind, I'm going to go to Dr. Kissel first, if that's okay?  I'll come back to you afterwards.
                  DR. WILLIAM DOUCETTE:  No, I don't mind.
                  DR. JOHN KISSEL:  Okay.  John Kissel.  I interpreted question 1 to be with respect to clarity and reproducibility of the document.  And I focused primarily on the dermal stuff because that's what I do.  And the dermal approaches are quite limited and straightforward.  So it's easy enough to follow.  That's different than declaring that they're technically good.  I haven't found any errors in the calculations so far, but I caveat that with I'm still doing spot checks.  So I reserve the right to come back to that.
                  On clarity, I have some kind of correction sorts of things.  I noticed -- and this is limited to things that have to do with dermal because that's where I was poking around -- that a citation of Shenk et al is in the reference list.  But it's not cited anywhere in the text.  So I don't know why it's in the reference list.  In Spreadsheets 13 and 14 of supplemental files 13 and 14, in the equation tabs the units are mis-specified for permeability coefficient and for exposure time.  Permeability coefficient should be centimeters per hour, not liters per hour.  And exposure time should be hours per day, not hours.
                  But those same variables are specified correctly in the input files or input tabs.  And so, they don't seem to be having any effect on the calculated result.  But it is confusing to have the wrong units on the equations spreadsheet.  And in Supplemental File 14, under NMP, that same permeability coefficient that I queried about earlier, because it's mysterious to me, the source is cited not as Poet (phonetic) as in the text, but as Atkinson (phonetic), which doesn't seem like a likely source.  So I have no idea why that reference is given there.  Those are the specific comments I have.
                  DR. DANIEL SCHLENK:  Thanks, John.  Dr. Davies.
                  DR. HOLLY DAVIES:  Yes, hi, this is Holly Davies.  I wanted to mention a little bit of what Bill was talking about with fenceline monitoring and also kind of flipping and looking at risk and where do we see the risk because that's really what our air quality program does in our environmental agency, right?  They know the facility.  They're looking for -- they have monitoring data, and they look -- is there risk at the fenceline?  Is it possible for a member of the public to be in an area where it's close enough to see risk?  And I see this exercise from EPA as being different than that.
                  Although, all the data that the states have would be good for validating it because they certainly do have a lot of monitoring.  We have oil refineries here.  We also have chemical plants.  We have a lot of pulp and paper mills.  So we do have a lot of large facilities with a lot of data on the fenceline monitoring.  Something that George mentioned, one of the comments, the notion of how useful or not useful this exercise is, I just didn't want to let that sit.
                  That seems like an important thing for the Committee to discuss, right, as we're going over these few days.  I wouldn't put a pronouncement on now, but I think that's important for us to talk about and get either consensus or not to consensus.  And, lastly, I would start with mass balance if I was trying to look at where everything is.  I would start with how much methylene chloride is produced, how much is captured by TRI?  All those questions, again, that someone had given George that he brought up are really good questions to answer.
                  DR. DANIEL SCHLENK:  Okay.  Thank you.  Dr. Chaisson.
                  DR. CHRISTINE CHAISSON:  Thank you.  First, my complements to the lead and the associates.  That was incredibly thorough.  And I'm just really impressed.  I wanted to sort of present my big concerns that have to do about data or values used, even if they weren't from data, in both the screening tool itself or the models on which it relies for other values that were mentioned.  I had asked EPA -- I can't -- I tried to go back and take a look at kind of what was the magnitude and the variabilities or what are we talking about?  Are we using average data, or are we using some kind of central tendency?  Are we using maximums or whatever?
                  There doesn't appear to be a standard of use -- best practices of use for applying any of these values or even knowing what kind of values were used by EPA or, for that matter, anybody who uses it.  So I have sort of three levels of concern about the values that I'd really appreciate hearing the discussants address this.  The first one is this term that keeps showing up, including in the assistant administrator's presentation today, which was this idea of readily available information.
                  I mean, I think we all have some kind of picture of what that probably is, but I can't find any standards which require a reviewer or an assessor to go out and find the data.  And clearly we've heard many, many instances, including from the public comment, where information's been supplied to EPA which is usually coming in through their comments on individual assessments.
                  But it's just not accrued for application on the next assessment, or somehow it's ignored.  I mean, the National Tribal Council has, I know, very frequently supplied information to EPA which goes unused, and I'm sure there are many other groups, including industry, which could say the same thing.  So, two points on that, one, what do people think would be sort of a minimum package of where you should go?
                  There must be information about many of these metrics from the states or from other groups who are compiling information.  And, also, what about some kind of very formal EPA portal through which groups, whether it's industry or communities or whatever, provides actual information detailing the pedigree, if you will, of that information which can be reviewed.  And then, once it's reviewed, it will be used somehow with some guidance and best practices for this kind of thing.
                  Now that's not just as a matter of contamination values or emission values.  It could also be very definitely on the many other factors which go into the calculations and are sometimes hardwired in these algorithms in these models and which also should include the values that would be employed in the routes of exposure not included in this because I'm going to argue strenuously for inclusion of dietary, for example, as part of this.
                  And, also, as I think the transparent standards for best practices, should you be defining -- or definition of the value, are you using a point value or using a point from a distribution?  What was the genesis of that value?  Was it modeled and further monitored -- should accompany every evaluation, so every value that's in an algorithm I think should be listed and be transparent so we know what kind of numbers were used here because sometimes the ranges are orders of magnitude.
                  So, whether you're using -- if you're using a central tendency, that's going to really throw the calculation one way or another.  Or, if you're using an accumulation of values that are either maximum or central tendency, you're going to be able to jerk these answers around a lot and affect the outcome.  And it won't be visible without listing that.  And, by the way, I think that needs to be stipulated before Bill Doucette's suggestion could be executed, which I thought was really a great idea, Bill.  So, anyway, that's my -- Dan, I'll send you those points if you would like them.
                  DR. DANIEL SCHLENK:  Actually -- yeah, you need to send them to George, actually.
                  DR. CHRISTINE CHAISSON:  Oh, okay.  Okay.
                  DR. DANIEL SCHLENK:  All of the people that haven't --
                  DR. CHRISTINE CHAISSON:  Oh, yeah, that's right.  I forgot.
                  DR. DANIEL SCHLENK:  -- been assigned to those questions should be sent to George.  And he will compile that.
                  DR. CHRISTINE CHAISSON:  George, I'll send you those comments if you like.
                  DR. DANIEL SCHLENK:  Okay.  Yeah, let's, I've got Dr. Gribble, Dr. Ferry, and then hopefully we'll get Bill in here before 5:00.
                  DR. MATTHEW O. GRIBBLE:  Thank you.  This is Matthew Gribble, temporary member of the SACC from University of Alabama at Birmingham.  I appreciated the summary that Dr. Cobb provided of most of my comments on the charge questions provided to him prior to the meeting.  I did want to highlight a few issues that have not gotten a ton of discussion.  The first is the issue of the 10,000 meter buffer being an arbitrary equidistant circle around the polluting facility and the need for incorporating environmental fate and transport considerations for actual fenceline community definitions.
                  So, Dr. Li highlighted that there were chemical properties of the example chemicals that were consistent, but for non-reactive longer dispersion air pollutants there may be a longer distance than 10,000 meters, potentially still qualifying as downwind of the polluting facility.  So I thought that that consideration might require specific consideration of those site and environmental contaminant characteristics for more case-by-case risk assessment, rather than just drawing a one-size fits all circle.
                  The second comment was that the example data that they were talking about was EPA six year review data authorized under the Safe Drinking Water Act.  Unfortunately, that's only available for a very limited number of contaminants.  And for unregulated contaminants, only a limited number are sampled through the unregulated contaminant monitoring rule data.  So there's a lot of chemicals that'll be assessed under TSCA.  And I thought it was unclear for some of the emerging contaminants what the data sources might be.  And I'm aware that there are non-regulatory datasets, for example, within the U.S. Geological Survey, for environmental surface water monitoring that may or may not be useful to Agency staff as they're looking to do these fenceline community assessments.
                  But I thought that relying on six year review data would be unrealistic for a lot of emerging contaminants.  And my last issue for this is just noting that the focus on surface water direct releases into a receiving water body is, as has been discussed and I'm sure will continue to be discussed in later charge questions, a very narrow definition of water pollution and concern for communities that maybe are relying on the water body for subsistence fishing or for groundwater or other non-potable uses.  I think it bears further consideration by Agency staff.
                  DR. DANIEL SCHLENK:  Okay.  Thank you.  Dr. Ferry.
                  DR. JOHN L. FERRY:  Hi there.  One thing that struck me -- and it has struck me all day -- is listening to people ask questions about the validity of the base data used to construct the models.  And I have noticed -- because EPA has a wonderful tool, the CompTox Dashboard, where they just have a really thorough compilation of data and molecular models together used to generate simple things like solubility, vapor pressure -- that, although they are simple, are still at the center of these exposure risk models.
                  And the few pieces of those data that seem to be reported in the Excel spreadsheets did not agree with the values on the CompTox Dashboard.  And, in fact, I couldn't find any citations of the CompTox Dashboard in the document itself.  Some of the variations were significant, differences greater than, say 15 percent, between the Dashboard and the citations used in the document.  So I just thought I'd point that out with respect to the question about repeatability here, George.  It would be nice to see some consistency for the data sources here.  And they've already got a wonderful source with that Dashboard to re-cite themselves.
                  DR. DANIEL SCHLENK:  Thanks for pointing that out, Dr. Ferry.  Bill, can you get us out in five minutes?
                  DR. WILLIAM DOUCETTE:  I can get us out sooner than that.  So, Dr. Ferry just brought up the physical-chemical properties, and there is a table, Appendix A1, for the physical-chemical properties used in the case study chemicals, which was brought forward from the previous SACC reviews for those individual chemicals.  So I think they're consistent that way.  The other comment I wanted to make was to address Dr. Li's comment about all these compounds being -- I thought hydrophobic you said, or did you say hydrophilic?
                  DR. DANIEL SCHLENK:  I think he said hydrophilic.
                  DR. WILLIAM DOUCETTE:  Hydrophilic.  And, again, that's a relative term.  And I think in our previous review of the ten chemicals, the only one that I would consider very hydrophobic was a dye.  What was it?  PV, purple violet 29, and I think the reason that EPA didn't use this in the case studies is that there was no data available to describe its behavior.  And certainly no monitoring data.
                  So it would have been nice to include a compound that was more hydrophobic.  One was hydrophilic.  One was in the middle being volatile, but I don't think they were trying to pull it from the previous ten chemicals.  And I don't think that there was a big difference, other than that particular compound.
                  DR. DANIEL SCHLENK:  Okay.  Great.  Thanks, Bill.  So we're looking right at 5:00.  I don't want to shut off discussion completely.  I think what we'll do today is we've had a fairly long day with the presentation and the public commentors, et cetera.  And before I go back to the Agency to ask them for questions or clarifications, let's go ahead and stew on this for tonight.  And then, we'll begin with a discussion in the morning.
                  You can view -- George, if you --I'm sure you've circulated your comments to your associate discussants.  But, again, for those of you that have provided -- we can't send those out to the entire panel, but to those that have provided comments if you want to look at some of those -- the written document to see if you want to add in or chime in on some of those points, where we can change discussants to Committee members and see whether or not we can get consensus on any of those points.  That would be great.
                  And, George, if you could, again, assimilate these in bullet points at some point where we could make it a little easier for us to get to the executive summary, that would be great.  If you guys could kind of rank those in terms of importance, that would be fantastic.  And if we can start on that in the morning, and then -- yeah, then we'll go back to the Agency and ask them for questions or clarification at that point and then move forward.  How does that sound?
                  DR. GEORGE P. COBB:  When do you want those bullet points, Dan?  By the report or for tomorrow?
                  DR. DANIEL SCHLENK:  You know, as soon as you can get them.  But I think at this point it's just out for discussion, if we can actually get those things, but that would be -- at this point get it -- I think getting your written comments out to everybody who had comments today, and then, after that, then we can assimilate.  Maybe after the discussion tomorrow you could get the bullet points off of that.  Yeah.  Okay?  With that, let's go ahead and adjourn for today.  And we'll start bright and early tomorrow.
                  If you guys could be here at 6:45 -- or sorry, 9:45 Eastern, there's a couple things I'd like to sort of talk about, particularly with the chat box components there.  Some of you, I guess, don't know that you can have direct contact with the chat box, and it doesn't necessarily have to go to everyone.  But let's meet -- if we can do that beforehand, that would be fantastic.
                  DR. ALAA KAMEL:  Thank you very much, Dr. Schlenk, for chairing the session today.  Thank you for the SACC Committee Members and for the ad hoc reviewers.  And thank you for the public commentors today and thank you for the EPA presenters that made presentations today.  And we hope to see you again tomorrow.  And today the meeting will be adjourned.  Thank you very much.
                  DR. WILLIAM DOUCETTE:  Thank you.  Bye.
                  DR. ALAA KAMEL:  Bye.

                        [MEETING ADJOURNED FOR THE DAY]

OPENING OF MEETING - DAY 2

                  DR. ALAA KAMEL:  Good morning, everyone.  My name is Alla Kamel, and I will be serving as the Designated Federal Official to the U.S. EPA Science Advisory Committee on Chemicals for this morning.  For this meeting and in my role, I will be opening the second day of the public meeting on EPA's draft TSCA Screening Level Approach for Assessing Ambient Air and Water Exposures to Fenceline Communities Version 1.0.
                  I'd like to repeat that SACC meetings are subject to all FACA requirements.  These include open meetings, timely public notice of meetings, and document availability to the public.  All documents are available to the public in the docket at www.regulations.gov.  Also note that this meeting is being webcast, transcribed, and recorded, and a live stream of today's meeting is available on YouTube.  See the link on the meeting website.  Also, there is a link to yesterday's meeting on the same website.
                  We had a very successful opening day yesterday.  I would like to thank EPA's assistant administrator, Dr. Michal Freedhoff, for her welcome and introductory comments.  I would also like to thank the Deputy Director for Management of the Office of Pollution Prevention and Toxics, Mark Hartman, and, also, would like to thank Dr. Kevin Vuilleumier and Rehan Choudhary for OPPT's presentation on the methodologies and the responses to the SACC questions.  Thanks are also due to the public commenters for all their presentations.
                  Yesterday, the Committee responded to Charge Question 1, and I would like to thank Dr. George Cobb, the lead discussant for this Question 1, and the associate discussants, Dr. Bill Doucette, Dr. Lucas Henneman, Dr. Li Li, and Dr. Rick Reiss.  Now, I would hand the meeting over to the Chair, Dr. Daniel Schlenk.  Thank you.
                  DR. DANIEL SCHLENK:  Good morning, everybody.  I'd like to begin today's meeting with a roll call of the Committee members if that's possible.  If you're here, just please answer "present" or "here."  I'll just go alphabetically through our list.  Dr. Apte.
                  DR. UDAYAN APTE:  Present.
                  DR. DANIEL SCHLENK:  Dr. Baker.
                  DR. MARISSA BAKER:  Present.
                  DR. DANIEL SCHLENK:  Dr. Blystone.
                  DR. SHERI BLYSTONE:  Present.
                  DR. DANIEL SCHLENK:  Dr. Calder.
                  DR. RYAN CALDER:  Present.
                  DR. DANIEL SCHLENK:  Dr. Chaisson.
                  DR. CHRISTINE CHAISSON:  Present.
                  DR. DANIEL SCHLENK:  Dr. Cobb.
                  DR. GEORGE COBB:  I'm here.
                  DR. DANIEL SCHLENK:  Dr. Davies.
                  DR. HOLLY DAVIES:  I'm here.
                  DR. DANIEL SCHLENK:  Dr. Doucette.
                  DR. WILLIAM DOUCETTE:  Present.
                  DR. DANIEL SCHLENK:  Dr. Ferry.
                  DR. JOHN FERRY:  Present.
                  DR. DANIEL SCHLENK:  Dr. Gribble. Dr. Gribble?  Okay.  Dr. Heiger-Bernays.
                  DR. WENDY HEIGER-BERNAYS:  Present.
                  DR. DANIEL SCHLENK:  Dr. Henneman.
                  DR. LUCAS HENNEMAN:  Present.
                  DR. DANIEL SCHLENK:  Dr. Johnson.
                  DR. MARK JOHNSON:  Here.
                  DR. DANIEL SCHLENK:  Dr. Kissel.
                  DR. JOHN KISSEL:  Present.
                  DR. DANIEL SCHLENK:  Dr. Li.
                  DR. LI LI:  Present.
                  DR. DANIEL SCHLENK:  Dr. Messerlian.
                  DR. CARMEN MESSERLIAN:  Here.
                  DR. DANIEL SCHLENK:  Okay.  Gotcha. Dr. Przybyla.
                  DR. JENNIFER PRZYBYLA:  Present.
                  DR. DANIEL SCHLENK:  Dr. Reif.
                  DR. DAVID REIF:  Present.
                  DR. DANIEL SCHLENK:  Dr. Reiss.
                  DR. RICK REISS:  Present.
                  DR. DANIEL SCHLENK:  Dr. Rowlands.  Dr. Rowlands?  Okay.  Dr. Sathyanarayana.
                  DR. SHEELA SATHYANARAYANA:  Here.
                  DR. DANIEL SCHLENK:  Dr. Unseld.
                  DR. MONICA UNSELD:  Present.
                  DR. DANIEL SCHLENK:  Dr. Vorhees.
                  DR. CHARLES VORHEES:  Present.
                  DR. DANIEL SCHLENK:  Let's go back.  Dr. Gribble.
                  DR. MATTHEW GRIBBLE:  Present.  Sorry about that.
                  DR. DANIEL SCHLENK:  No worries.  Dr. Rowlands.  Dr. Rowlands?  Okay.  Hopefully, he doesn't have the audio issues again there.  Okay, thank you for that.

PANEL MEMBERS: FOLLOW-UP ON PREVIOUS DAY

                  DR. DANIEL SCHLENK:  The plan for today, as I mentioned yesterday, was we'll finish discussions on Question 1 that was provided by the Agency.  Some of the comments that were presented and discussed, I would like to sort of finalize that discussion, and then move forward to the Agency and ask them for questions or clarification at that point.  Let's continue the discussion of Question 1.  Dr. Cobb had presented a fair amount of information.  There were some other comments that were provided after that.
                  At this point, do we have consensus, I guess, at this particular point?  Is there some discussion about some of the points raised in terms of whether or not those are part of the consensus?  How many Committee members feel strongly about those points?  At this point, let's go ahead and continue that.  Does anybody have any further input for Question 1 at this time?  A little sleepy this morning, I guess?  Any other comments?
                  Okay.  I guess, George, you have what you have.  Yeah, if you can put that together, that would be fantastic.  At this point, then, let me go to Rehan and ask if he has any questions regarding the comments that were made yesterday, questions or clarification.
                  DR. REHAN CHOUDHARY:  Good morning, everybody.  This is Rehan Choudhary from the EPA.  I think the first charge question was really focused on clarity and us trying to understand what we could enhance and revise if reviewers, such as yourselves, were trying to look through something, reproduce something, and you weren't able to do so.  I think the way you provided and laid out that feedback is very helpful to us.  The way it was being presented, it felt that, if -- section this, line this, this could use improvement or enhancement.
                  If that's the way it comes to us, I think it'll make it very easy for us to go through it and try and tackle and address those items and hopefully make those items clear.  The only thing I would highlight is -- I know the first question was focused on how the report and technical aspects were presented, whether they were clear.  There was a lot of focus or discussion around uncertainty of the approaches yesterday.  We'll see how that carries over into subsequent charge questions.
                  But that's really something we are looking forward to hearing from the SACC panel itself, with respect to the expertise you bring.  Does the uncertainty lean conservative?  Do you think it's not conservative enough?  What particular or specific actions could the EPA take to address those uncertainties?  I think that would be very helpful to us.  I think I'll stop there.
                  DR. DANIEL SCHLENK:  Okay, great.  Dr. Johnson, you have your hand up?
                  DR. MARK JOHNSON:  Yes.  Sorry, Dr. Schlenk.  It took me a while to go through my comments to see if I missed anything.  But there was one for clarity that you may want to consider.  On page 25, Figure 2.3, if you follow the logic in the figure, if the data do not exist, either analytical or modeled, further evaluation and refinement is called for.  If you just look at the figure, it's unclear.  You have more explanation in the text.  So I suggest maybe the language in the last box be changed to "consider evaluation of alternative or surrogate data sources or collection of further data" just to be a little more explicit to the reader for that figure.
                  I do have some other suggestions, but I think they fit better under other questions.  I'll just wait on those to get to those questions to provide that.  Thank you.
                  DR. DANIEL SCHLENK:  Dr. Blystone.
                  DR. SHERI BLYSTONE:  I've been debating whether to bring this up for Question 1 or somewhere else.  But I think, because it's clarity, I'll bring it up here.  This is very general around the title of the document and the use of "fenceline communities."  I know the EPA does define fenceline communities in there, but I think, when you say that, people get a picture in their mind.
                  So I think there could be some further clarity around the scope of what this document covers, going from an industrial facility with a fence that people might think of when they're talking about fencelines down to those small commercial facilities that might be in a neighborhood.  It was brought up a couple of times yesterday.  But I think that the EPA could perhaps make it more clear, the broad scope of things that they're trying to cover with this guidance.
                  DR. DANIEL SCHLENK:  Great.  Dr. Davies.
                  DR. HOLLY DAVIES:  Since Sheri brought this up, I'm going to agree with her.  When telling people I was looking at this fenceline document, a lot of quizzical looks, people not knowing what it was.  I think it would be good to have more explanation around that, more descriptive.
                  DR. DANIEL SCHLENK:  Okay.  Now everybody's waking up, I guess.  Dr. Unseld.
                  DR. MONICA UNSELD:  Yes.  I wanted to also support Dr. Blystone's comments.  I think if people look at it in terms of disproportionately impacted or something with a little more clarity, we understand that it's going to bring in other routes of exposure, not necessarily just living next door.  If it's disproportionately impacted, that's one way you can bring in the fact that you may have a Dollar Tree that has more toxic products instead of a Target in your community or your diet or something like that.
                  DR. DANIEL SCHLENK:  Okay.  George, hopefully, you're getting these comments as well.
                  DR. GEORGE COBB:  I am.  I'm capturing these.  I'm putting notes in the document now.  Sheri and Holly -- and I'm sorry I wasn't looking at the last speaker -- thanks for those comments.
                  DR. DANIEL SCHLENK:  Dr. Unseld.
                  DR. GEORGE COBB:  Some of this is already there, and we'll just double check to make sure it's sufficiently detailed for your needs.
                  DR. DANIEL SCHLENK:  Great.  Okay.  Any other comments on Question 1 before we move on?  Dr. Choudhary, please.
                  DR. REHAN CHOUDHARY:  Yes.  Some of my teammates brought to my attention one thing we did want to bring forth for the panel again is the way the opening was done yesterday with Dr. Michal Freedhoff.  This screening level approach, Version 1.0, it has a specific purpose, to try and address seven of the first ten risk evaluations.  It's been put forth in such a way where we think we can expand its capacity for subsequent risk evaluation.
                  That's a dichotomy that I would really like to reemphasize and remind everyone that we're trying to do something with seven of the ten risk evaluations that have already been completed.  Is the methodology as is?  What can it do for that?  Then how can it be expanded for newer risk evaluations we do?
                  DR. DANIEL SCHLENK:  Great.  Thank you for that comment.

CHARGE QUESTION 2

                  DR. DANIEL SCHLENK:  Okay.  Let's go ahead and move on to Question 2.  If we can, put that up and read that into the record.  Thank you, Mr. King.
                  DR. REHAN CHOUDHARY:  All right.  This is Rehan Choudhary from the EPA.  Charge Question 2 to the SACC Committee: "For instances where EPA is focused on the potential impact of a single release source, air or water release, for a given condition of use, or COU, is it reasonable for EPA to use this screening-level approach, Version 1.0, to conclude that chemical exposure from a single-release source for a given COU is not a concern if exposure results of the methodology, when compared to relevant toxicological benchmarks, do not indicate any potential human health risks to fenceline communities?
                  In your response, please provide examples or explanations to support your conclusions or suggestions."
                  DR. DANIEL SCHLENK:  Okay.  Our lead discussant for that is Dr. Przybyla.
                  DR. JENNIFER PRZYBYLA:  Good morning and thank you for everyone who commented on this question.  I collated and summarized the responses as best I could.  Any omission was purely my mistake and not intentional.  Please feel free to, at the end of this, speak up if I unintentionally left out any of your responses.  SACC members have identified several major limitations to using a single-release source for the screening-level approach, including first, as we recognize that as a screening approach, it is best used as a first step in a tiered assessment to identify areas where a more detailed review may be called for.
                  At least one Committee member noted that, as there are numerous conservative assumptions in the approach as drafted and it could reasonably be used to focus further risk evaluation on areas where a concern is indicated for the pathways and receptors included, the lack of consideration for cumulative exposures, multiple-source exposures, or additional risk factors, such as stress, poverty, and/or diet, that can synergistically affect environmental exposures may underestimate the adverse effects from the environmental exposures in fenceline communities.
                  Also, there is a concern that there are sources that are not reporting emissions, yet still contributing to exposures.  Additionally, there is not the ability to incorporate existing background concentrations of contaminants when conducting the single-source analysis.  These are complex issues, and the Committee recommends that any changes to EPA's approach to include such issues go through the peer-review process.
                  The current screening process does not address fenceline communities that rely on private domestic wells as groundwater contamination is possible.  The water pathway exposure assessment focuses solely on surface water, which may underestimate exposure.  Additionally, the E-FAST model may underestimate concentrations because it assumes an equilibrium between water and the atmosphere when concentrations of organic contaminants may be influenced by absorption to soils.
                  Similarly, there is a significant uncertainty related to emissions to air and how much of that will partition into water, as was pointed out in previous SACC meetings.  This is a reason that monitoring data are essential.  Based on volatilization assumptions of wastewater treatment plants, airborne releases from these facilities would serve as sources for toxicants of concern.
                  The screening analysis relies heavily on one type of data for each medium with many assumptions for modeling that does not represent all communities, especially tribal and indigenous communities.  Concerns were raised about the accuracy and completeness about the data used to conduct the screening analysis.  Specifically, there is concerns about the accuracy of TRI and NIEI data and that the TRI data lacks inclusion of emerging contaminants, such as PFOS.  Also, exact discharge locations must be known.
                  Otherwise, a worst-case scenario for release points should be used.  There's a concern about using circuit data instead of monitoring data at the full-screening phase.  Additionally, the SACC members identify that the models used to estimate exposure failed to account for societal shifts, like the recent increase of working and schooling from home, and the meteorological models failed to incorporate potential changes or disasters driven by climate change.
                  At least one member suggested closer distance should be modeled for inhalation risk.  Field analysis does not include conclusions on fenceline risks to animal or plant populations, which is unlikely to be captured by TRI data.  There is a lack of explanation on how limited toxicological evidence for health endpoints or benchmarks is addressed.  Because the TRI data has zero-emission dates, it is unclear how noncontinuous exposure is addressed and if this could be an overestimation of risk by averaging in zero-emission days into exposure days.
                  Because of these reasons, it was suggested that EPA does not make definitive conclusions using single-release source analysis unless there is a high degree of uncertainty that there is truly a single source and instead make conclusions about the screening including both "failed to detect" and "indication for concern," or that a chemical can be "reasonably anticipated" to cause a health effect.
                  DR. DANIEL SCHLENK:  Okay.  Thank you very much.  Our associate discussants for Question 2 are Sheri Blystone.
                  DR. SHERI BLYSTONE:  Hello.  Jennifer did a great job.  I have nothing to add.
                  DR. DANIEL SCHLENK:  Thanks.  Our second associate is Sheela Sathyanarayana.
                  DR. SHEELA SATHYANARAYANA:  I think that was a great summary, and I had submitted my comments before.  The only thing that I would add is that there were some differences of opinion I saw in the comments that came in.  I think one of the things you read is that "the Committee recommends," and I'm not sure that that was really the case for that comment.  It was just one person who recommended that.  I'm just trying to make that clear, that sometimes there are differences.
                  That was with respect to combining environmental exposures and nonchemical stressors, which is an emerging area of science and certainly an emerging area of risk assessment and deserves significant attention with respect to fenceline communities.  I just wanted to raise that one point.
                  The other point that I wanted to make is that Rehan had talked about how do we apply this to past chemicals, so at least to the first chemicals that have already been reviewed?  One of the things that's come up with some of the chemicals is that sometimes there's no health data at all on those chemicals.  Then they're making conclusions based on no health data or trying to make conclusions based on no health data.  There was a lot of discussion about how to do that in past SACC meetings.  There was no discussion of that in this report.  So it would be great to see that here in terms that Version 1.0 and moving forward is incorporating an approach there that reflects, maybe, some of the comments from SACC in the past.
                  DR. DANIEL SCHLENK:  Okay.  Great.  Thanks.  Dr. Vorhees.
                  DR. CHARLES VORHEES:  Yes.  I think Jennifer certainly captured all my comments, and I don't have anything further to add.
                  DR. DANIEL SCHLENK:  Dr. Ferry.
                  DR. JOHN FERRY:  I don't have anything to add.  Thank you.
                  DR. DANIEL SCHLENK:  Okay.  Any other Committee members?
                  DR. MONICA UNSELD:  I have a question.  This is Monica Unseld, and this is just a clarification.  When saying recommendations from past SACCs, are you saying that, when Version 2.0 comes out, they should mention that previous SACCs have asked for this?  I just want to make sure I'm on the right page.
                  DR. DANIEL SCHLENK:  Who are you directing the question to?
                  DR. SHEELA SATHYANARAYANA:  Probably me.
                  DR. MONICA UNSELD:  Yeah.
                  DR. DANIEL SCHLENK:  Okay.
                  DR. SHEELA SATHYANARAYANA:  This is Sheela.  I guess, what I was saying is that, when there's been no health data -- basically, at different times we've suggested, or certain members have suggested -- that you cannot make necessarily a risk determination when you have no data in front of you.  That has been put into previous SACC assessments.  It's taking that into consideration or at least adapting an approach.  Certainly, the suggestion is not to not do a risk determination but certainly to take that information into account to create a new approach when there is no health data.
                  DR. MONICA UNSELD:  This is Monica again.  Thank you.  I know yesterday people had commented that SACC had already received this.  I just wasn't sure if the process was SACC says something, and then it goes into the oblivion, or should we expect the next version to reflect that SACC said something.  Thank you.
                  DR. DANIEL SCHLENK:  We all have our opinions on that comment sometimes, I think.  Dr. Kimmel.
                  DR. JOHN KISSEL:  Kissel?
                  DR. DANIEL SCHLENK:  Oh, sorry. Sorry about that.  Yes.
                  DR. JOHN KISSEL:  There is a Kimmel, or was, at one time.
                  DR. DANIEL SCHLENK:  Yeah.  I know.
                  DR. JOHN KISSEL:  I guess my first point in response to the question is, is this useable?  I would say that, first and foremost, I don't know where the Committee's going to come out.  If there's a dissenting opinion, I want to be on that side.  I don't think it's usable because I think it leaves out too many pathways.  Screening is supposed to be conservative.
                  The first reason that this is not conservative, although individual assumptions might be conservative within the pathways that are actually considered, there's so many pathways that aren't considered that it, overall, can't be considered conservative.  In particular, I'm concerned that we still aren't getting to groundwater.  The history of groundwater contamination near industrial facilities and commercial facilities is so extensive that ignoring it is just not acceptable at this point.
                  That would include both groundwater transport and consumption of the groundwater and soil vapor transport in the vadose zone.  I would point out that EPA has online something called the Regional Screening Limits calculator, which you can go use, and it has both a soil-to-groundwater and a fish pathway in it.  So EPA already has existing methods for addressing some of those concerns and chose to ignore its own methods in putting together what we've seen in this document.
                  Again, I'm particularly focused on dermal pathways, so I will point out more specifically how dermal pathways are not conservative.  There's no vapor-to-skin in this document.  All we have is the swimming pathway, so recreational exposure to water and then absorption from water into a human being.  As someone pointed out earlier, tap water is also contacted dermally, and so that pathway is not here.
                  Now, for some of these things, the particular compounds we're looking at wouldn't be very important, but in a screening calculation, you can do that calculation and then demonstrate it.  For instance, in RAGS Part E from 2004, there is a calculation of an oral-to-dermal ratio.  It's actually dermal-to-oral ratio.  It's an EPA methodology.  It already exists, and it allows you to estimate the relative importance of bathing exposure to skin to drinking tap water.  For the compounds that we're talking about here, that number's likely to be low.  Then you can say, okay, we can leave out the dermal pathway.  But you need to do the calculation first and demonstrate it.
                  The way you do screening is you don't decide to toss stuff out; you do calculations and say we can then toss stuff out.  That methodology already exists in EPA's toolkit, and they ignored it.  The vapor-to skin, which actually is potentially much more important, the methodology was developed by Weshor Nazorov (phonetic) in the early 2010s, and it has now been adopted.  It can be found in the Computer Exposure Model.
                  EPA has worked up the methodology that Weshor Nazorov developed.  They have it in their own handbooks.  There is something called the DI Ratio, which in the Weshor Nazorov case, is the dermal vapor-to-skin ratio.  The physical chemistry here is a little, maybe, surprising, but there are a few compounds for which the skin actually takes up material from vapor as efficiently as lungs do or maybe even more.  Most chemicals don't work that way, but a few do.
                  I've been urging EPA, in the TSCA process, to screen all the chemicals for this particular phenomenon.  Last night, I did the calculations for our three chemicals.  Methylene chloride and 1-Bromopropane come in fairly low.  NMP has a dermal vapor-to-inhalation ratio which is much greater than one.  And for compounds like that -- this is the old problem in industrial hygiene -- you just do an inhalation exposure, and you say you're done.  That may or may not be how people are actually exposed.
                  So the air standards by themselves may be not protective at all.  I think EPA already knows this.  They already have published a method, and they aren't using it here.  That's not conservative.
                  Two other points, the dermal methodology that is here assumes steady-state absorption, which is okay for compounds with low lag times.  So three-hour exposure would reach steady state if you had a compound that has a lag time for penetration of the skin of about half an hour, which, again, we're talking about solvents.
                  They go through skin pretty fast.  It's not a bad assumption for these compounds.  But if it's the generic method that will be applied to all compounds coming up later, and you have more lipophilic compounds that are slower to go through the skin that dissolve into the skin relatively easily but then they don't pass through it relatively easily, then a steady-state assumption is a bad assumption and will underestimate total uptake.
                  If you take a person with clean skin and you expose them to a chemical, the first thing that has to happen is the absorption capacity of the skin has to be filled.  So before you see it and then come out the other side of the skin, you have to fill up the membrane.  That's basically the lag time.  For compounds with a low lag time, then a steady-state assumption will underestimate short-term uptake badly.  So that's a problem.
                  The last bit is the release days versus exposure days issue, as one of the public commenters point out the other day.  There was a great example in West Virginia, that coal cleaning chemical.  It got dumped into the Kanawha River.  The event lasted not very long because the tank just drained right away.  But once it got into the water distribution system, then the exposure lasted weeks because water distribution systems are very difficult to purge.  The exposure went on for much longer than the number of release days.
                  Those are the things that I have written down.  I am done for now.
                  DR. DANIEL SCHLENK:  Thank you, Dr. Kissel.  Please, if you can get that information to Jennifer, that'd be great.  Dr. Heiger-Bernays.
                  DR. WENDY HEIGER-BERNAYS:  Yes.  I concur with the presentation that had already been made.  In addition, I do agree with Dr. Kissel's comments and was actually going to make similar overarching comments regarding the utility and reproducibility of the method.  With regard to the reproducibility of the methods, it's really about the lack of inclusion of relevant pathways, specifically because this is a screening assessment where one would screen in order to eliminate irrelevant pathways.
                  With regard to single COUs, as was specifically asked in the question from a single-release source, it is useful to examine the COU and to understand which of the COUs are the drivers of occupational exposure and risk.  It's also useful for understanding how much additional risk can be attributed to the nonoccupational exposures and vice versa.
                  The approach as presented does not allow for the well-documented evidence that people who work in these facilities often live nearby, and there are a lot of mobility data that are available.  I'll make this specific in my written comments.  Studies from take-home hazards often do have release data that connect the location or facility with where people are living.
                  With regard to the toxicological benchmarks, while the POD selection is based on published and vetted literature and prior EPA Committee work, EPA has the opportunity here and the ability to use the recommendations that were suggested in one of the commenter's statements yesterday.  Those are the recommendations of the National Research Council in 2009.  And these include harmonizing the approaches to non-cancer and cancer risk assessment.
                  Not only is it useful to have a single approach that conveys both the uncertainty in the POD selection and is more readily translatable but also addresses the fact that responses are variable amongst people in the population.  Using this probability approach also recognizes that the epidemiological data on health effects associated with exposure to these three chemicals, but also looking beyond that will be in the TSCA docket, have non-cancer effects at increasing doses but also have a suite of effects that can be formally recognized and should be important, allowing the regulators to make decisions to make exposures below the point of departure.
                  Now, for screening, that may not be as important.  But, quantifying non-cancer health risks due to environmental exposures is important to contextualize population-level health effects and allow more thorough assessments and allow, frankly, additional information to be gleaned if the screening risk assessment is intended to be used as EPA presents, where it will be used to make more specific analyses.
                  Second, if the point-of-departure approach is used as demonstrated in the screening assessment, uncertainty and variability do need to be accounted for.  We've heard this in other comments.  But this information should be gleaned from the scientific literature, of which I know that EPA is aware.  Of specific concern is that the selected point of departure needs to be supported in light of the health data, the epidemiological data, the non-animal data, the NAMs that EPA is using, has developed, and certainly has the capability to use in developing and examining that point of departure.
                  People's sensitivity to chemicals is dependent on biology, and the biological response is a function of health, also, at the time of that exposure.  So for people who are older, who have experienced infectious diseases, young children, and even presumably healthy young adults, respond to exposures with a suite of outcomes.  It could be that, at the screening assessment, there isn't this level of detail but certainly perhaps an uncertainty factor to account for these biologics when assessing risk, particularly for the screening-level approach.
                  With regard to the NAMs, there has been amazing work and advances done at EPA itself and in, certainly, coordination with NIEHS.  I think that in the interest of moving forward quickly with the screening assessments, since that is the objective here, is not to, I believe, get bogged down so that nothing happens.  But I think that there's an opportunity here.  Maybe the opportunity is to recognize these, I'll call them, gaps in the current screening analysis and apply those, a series of uncertainty factors, directly to the points of departure or to the exposure estimates.  Thank you.  That's it.
                  DR. DANIEL SCHLENK:  Okay.  Thank you very much.  Dr. Davies.
                  DR. HOLLY DAVIES:  Hi.  I wanted to bring up the insufficiency of the way the method goes from this very general TRI data, data that people have mentioned coming from one survey for things, and then going to specific points on a map and just kind of drawing the concentric circles because, once you're at a specific spot on the map with the facility, then you do have so much more information.  You know is this spot in a valley where the air is going to behave differently.
                  I think, of course, of Washington state where the Columbia moves, and the air patterns change very locally there.  Then, it's not sufficient to say, through these circles, we don't see risk out to this point.  So, then, we don't see risk because there could be when you're talking about specific places.  So I don't think that's a sufficient way of doing it.
                  As I think someone mentioned yesterday, it doesn't take into account the changing land-use patterns.  To say there's currently no houses there doesn't take into account potential risk moving forward because TSCA's not about land-use patterns; TSCA's about chemical uses and what chemical uses are allowed.
                  The other point I wanted to bring up was -- I haven't done this yet, so this is kind of a placeholder -- looking at, basically, how we do permit and permit criteria and comparing that to the PODs.  I understand why EPA decided to take the PODs that we discussed for the initial risk evaluations and move those forward.  But of course, we have levels.  When we're looking locally for permits, we take into account other things.  But we look at what level it is as opposed to like where the risk is, how far out it is.  We'll look at the fenceline, how does it compare to the criteria?  Just as a note, I was going to compare the two different methods.
                  Although, of course, in some of our water quality criteria, we do take into account fish consumption, other pathways that people have mentioned here.  Thanks.
                  DR. DANIEL SCHLENK:  Okay.  Thank you.  Dr. Sathyanarayana.
                  DR. SHEELA SATHYANARAYANA:  I just wanted to make one point of clarification that Dr. Kissel's comments reminded me of.  They asked, "Is this sufficient," in the question.  I think, from the totality of the comments, the answer is no.  And I just wanted to clarify that I agree with "the answer is no" for a variety of reasons, many of which were brought up yesterday.  Often, when you're looking at the health characterization, it is so dependent on accurate exposure characterization.
                  In response to Question 1, there's been many, multiple comments about the exposure characterization not accounting for the multiple pathways, cumulative exposure, burden, and I think that that's what leads to the answer being no here.  I just wanted to clarify that point.
                  DR. DANIEL SCHLENK:  Okay.  Got that.  I lost you.  Bill, you had your hand up.  Got your question answered, I guess.  You're on mute.
                  DR. WILLIAM DOUCETTE:  I was going to let it go, but I thought maybe this is an okay time to bring it up.  It's been obvious to me through the last ten chemicals and this session here that there's a significant overlap in the responses to the general charge questions.  It keeps happening over and over again, and I'm not sure the best way to deal with that.  But part of it is that the questions are -- they're like leading questions.
                  I wonder if a section-by-section review is appropriate so that the general question might be, what are the main strengths and weaknesses of the document, and does it achieve its overall goal?  That way, we wouldn't keep repeating the same things over and over again.  That's just a comment based on, I guess, my frustration with the last ten meetings.  I thought we had discussed how the charge questions kind of focus you on areas that maybe they really shouldn't.  So I just thought I'd bring that up now, Dan, and I apologize for rambling on like that.
                  DR. DANIEL SCHLENK:  No worries.  I think what we've done in the past, Bill, if you recall, we usually have a comment period at the end where we say, yeah, maybe it'd be better to ask questions this way and make those recommendations.  I think we will do that again at the conclusion.  Again, I see your point in terms of the redundancy of the answers that are there, so we'll definitely do that at the end and make sure that that's a component of the report.  Yeah.  Dr. Johnson.
                  DR. MARK JOHNSON:  Thank you.  I also agree with the previous comment.  I want to point out that this really isn't a risk assessment; it is a screening assessment.  It does not estimate the probability of an adverse event occurring, which is the definition of risk.  There's no probabilities here.  We have quotients, or we have MOEs.  But I think the overall process is a reasonable one, specifically for these two chemicals.
                  If we have things that have different chemical/physical properties that we expect may be persistent, may not volatilize as readily, we may also want to consider other pathways that were discussed earlier, like wet and dry deposition and infiltration of the groundwater.  Maybe there's some adjustments that could be made, some of the ones that were brought up earlier by other commenters.  But I think the overall process is a relatively reasonable one.
                  You don't want to get bogged down into too much quantitation because I think it gives a false perception of precision.  Risk assessment by nature is one that uses a lot of assumptions.  It was definitely used a lot of assumptions here.  We've got to be careful not to take it too far as being precise.  It is not.  I think, overall, it roughly achieves the correct objectives, maybe requires a little more tweaking here and there.  I may want to make specific caveats given specific chemicals that have different chemical/physical properties.
                  DR. DANIEL SCHLENK:  Okay.  Thank you, Dr. Johnson.  Dr. Chaisson.
                  DR. CHRISTINE CHAISSON:  I think these have been great comments.  I just wanted to, once again, raise this.  When we're talking about something being conservative as an answer or not conservative enough or whatever, I do not think we actually know whether or not these calculations are conservative or not for two key reasons.  We don't know what the data or value choices were for many key components of the algorithms.  We do not know when they take a concentration in the air or in the water or whatever, and they start.
                  Then the process has many other factors in the algorithms that are chosen from handbooks or other sources.  We don't know if there was some kind of amortization across time.  I'm not criticizing it.  I'm just saying it's completely opaque.  So the summation of the effect of all of these other factors going into the algorithm could bring what initially looked like a conservative estimate down to something that is clearly not going to be viewed as conservative in its summation.
                  So in order to even have a sort of gut feeling as to whether it's conservative, at a minimum, all of those factors need to be identified and need to be defined as to where the value point was chosen.  Was this some kind of averaging number?  Was this an extreme?  Was it unique for a particular?  Was it a model number?  The reliance on other programs and just saying to somebody, you can go look it up, well, I tried looking some of this up, and it's laborious to begin with.  But it's completely opaque.
                  The second point is, especially when we don't know what health endpoints are going to be most critical for different life stages, we do know that there is an averaging or assumptions about how long the release is and over what period of time will the exposure be?  So that has a tendency to, if you will, dull down the spike events.  That is something that I think is a real concern in a screen.  Now, later on, in the more detailed risk assessments, that can be dealt with.  But in a screen, I question whether it's always appropriate to reduce by amortizing.
                  You can't tell the difference in those numbers whether you've got a long-term lower exposure or whether you have spikes.  I just want us to keep an eye on the ball when we're talking about whether it's adequate, whether it's reflecting upper bounds, or whether it's really conservative because I do not think the way it's constructed right now that we know the answer to that.  Anyway, that's my opinion.  Thanks.
                  DR. DANIEL SCHLENK:  Okay.  Again, let me also just remind folks to get their written comments in to the lead discussant as you're making these oral comments.  Dr. Choudhary, I'm going to get to you after I get through the Committee, okay?  At that point, we'll go back to you for questions of clarification.  Dr. Unseld.
                  DR. MONICA UNSELD:  Yes, this is Monica Unseld.  This is my first time being on an ad hoc committee, so maybe this is a clarification point.  We've said multiple times that the reality is that people are not exposed to a single use and that this is just not reflective of what reality is.
                  So it may be beneficial to say, like, and for purposes of screening before we get to risk assessment, this is why we are looking at one chemical, because I'm having difficulty seeing how you can look at one chemical and say that's a great screening method.  And then, let's just say, we take it out of the test tube, and it's chaos because it's not reflecting what's really going on.  So I'm not confident.  Again, this may just be a need for clarification as to how this screening is going to fit into reality.
                  As others, I also have many concerns that there are so many assumptions and estimates when some of these could be refined by just engaging with stakeholders and asking, where is the POD?  Where is the facility boundaries?  Are you in a river valley?  These sorts of things.
                  I wonder, when it comes to defending this, should it have to be that way?  Should we have a method of -- look, we have peer-reviewed literature, but we also have direct engagement with stakeholders.  So that's my comment.
                  DR. DANIEL SCHLENK:  Okay.  Any other comments from the Committee?  Dr. Chaisson, your hand is still up.  Do you have any -- no.  Okay.  If there's no further comment at this point, let's go back to the Agency and provide time for questions or clarification.  Dr. Choudhary.
                  DR. REHAN CHOUDHARY:  Yes.  Good morning, everybody.  This is Rehan Choudhary again.  As the discussions were ongoing, various technical members of the team wanted to clarify certain things.  I think there was a portion there that maybe got the TRI data being very general, and then how do we go from TRI data being general to identifying points around a facility, and are those representative of that particular geography?  The team wanted to clarify that, when we have TRI-reported data, we also have lat/long information for that facility.
                  The full screening methodology on the air side then tries to pick the closest meteorological data and stations and use those as being representative for those particular facilities.  So there is an attempt to go from -- okay, you've got TRI-reported data.  This is the geographical coordinate.  We pick the closest or most representative meteorological data or met data, and that's how we model those conditions.  I know the pre-screen does it a little differently, so we wanted to clarify.  The full screening methodology is more granular than the pre-screen.
                  DR. DANIEL SCHLENK:  So is that a question that you're providing or more information?
                  DR. REHAN CHOUDHARY:  It's a clarification because, like I said, based on the discussion, it felt like people were thinking the approach or TRI is generic, and how do you take into account geographic-specific information?
                  DR. DANIEL SCHLENK:  Sure.  I think that's their reading of the document.  So I just want to caution you in terms of trying to influence the Committee based upon additional information at that point.  At this point, they're reviewing the document as written, so they provide those comments to you.  I can't allow sort of a back and forth between the Agency and Committee at this point.  If you have questions of particular comments that require clarity, I can provide that.  It's not appropriate to banter back and forth.  I hope you understand what I'm getting at there.
                  DR. REHAN CHOUDHARY:  That's all right, Dr. Schlenk.  We just wanted to attempt to clarify, but we'll make note of that.  Thank you.
                  DR. DANIEL SCHLENK:  Thanks.  Any other comments?  Jennifer, I think you've got most of the info from folks.  Again, same type of approach here.  Just to provide this also to the lead discussants as well, this is during the discussion where you can modify your output to say, the majority of the Committee felt so and so.  Certain Committee members felt so and so and provide that as the initial document.  Then we can actually go forward with that aspect.  Again, I'd welcome the Committee to, again, view that document when it comes forward.
                  If you agree with a certain position and it says, one Committee member felt so and so, and you felt you agreed with that, you can say, several Committee members, and edit that when it comes to that particular point in time so that the clarity is portrayed in terms of whether there's a majority or consensus for that question.  Yeah, Dr. Vuilleumier.
                  DR. KEVIN VUILLEUMIER:  Thank you, Dr. Schlenk.  One clarifying question -- and it is asking for clarification just so we understand what the comment was.
                  DR. DANIEL SCHLENK:  Sure.
                  DR. KEVIN VUILLEUMIER:  One of the commenters indicated that they thought we should model at closer distances.  I want to clarify in what methodology is that referring to for pre-screening.  This is described in the report.  We did 100 to 100,000, 1,000 meters because that's the limitations of IIOAC.  For a full screening, we did five meters and then went out from there.  In what context were they referring to we should do nearer the releasing facility?
                  DR. DANIEL SCHLENK:  Is that Dr. Davies, or who made that particular comment?  I was looking for my notes.
                  DR. JENNIFER PRZYBYLA:  I believe that was George who made that comment.
                  DR. HOLLY DAVIES:  I don't think that was mine.
                  DR. DANIEL SCHLENK:  Okay.  George?
                  DR. GEORGE COBB:  I think that was me, Dan, but that was yesterday.
                  DR. DANIEL SCHLENK:  Yeah.  Okay.
                  DR. GEORGE COBB:  When you try to couple those models, and you've got one model that predicts concentrations down to a hundred meters, and then you're trying to model exposures inside that -- excuse me, risk inside that when you've got exposures, you don't know what those exposures are.  A better description of how that was done and trying to actually model something rather than choosing values is -- it needs to be better explained.
                  It would be better it if could be actually modeled in the package that exists.  It was unclear to me how that was done inside of a hundred meters.
                  DR. DANIEL SCHLENK:  Does that answer your question there, Kevin?
                  DR. KEVIN VUILLEUMIER:  I believe so.  It sounds like it's referring to the pre-screening methodology which is limited by the model.  For the full screening, we used AERMOD, which isn't limited to that, and we did model 5, 10, 30, 60, and so on out.  So it was much closer to the facility.  Thank you.
                  DR. DANIEL SCHLENK:  Great.
                  DR. GEORGE COBB:  I think you're right, Kevin.
                  DR. DANIEL SCHLENK:  Okay.  Any other questions from the Agency or clarification?  Okay.  At this point, we've been at it for an hour.  Let's go ahead and take a ten-minute break before we move onto Question 3 if that's okay.  Let the coffee move through, and we'll take a ten-minute break and come back for Question 3 at that point.  Let's go back at ten minutes past the hour.

                  [BREAK]

                  DR. DANIEL SCHLENK:  Okay.  Is everybody back?  Don't see any pictures; I'm just seeing names.  There we go.  Okay.  I just wanted to make a little point of clarification here too.  This is based on Dr. Choudhary's comments here.  I'm sorry to cut you off there, but if the Committee would like questions or clarification, they can ask the Agency for those points of clarification.  So if during your discussions and deliberations you've come up with additional questions, then that is totally okay.
                  You can then ask for that information from Dr. Choudhary or Dr. Vuilleumier.  If there's certain comments or questions that come up that you would still like additional information, then that is okay to ask for those points.  I just wanted to make sure you guys were aware of that, that that's a possibility at that point.  So before we go to Question 3, does anybody have any questions to the Agency in terms of more clarification?  Is everybody back?  Okay.  Thanks, George.

CHARGE QUESTION 3

                  DR. DANIEL SCHLENK:  Okay, so with that being said, let's go ahead and move forward, then, to Question 3.  We can put that on.  Thanks.  Dr. Choudhary, if you could read that into the record, that'd be great.
                  DR. REHAN CHOUDHARY:  All right.  Good morning, everybody, Rehan Choudhary from the EPA.  Charge Question 3 to the SACC Committee: "Keeping in mind that EPA's intent is to develop a screening-level approach, please provide any practical suggestions you may have for enhancing Version 1.0 of EPA's screening-level approach with respect to air and water release estimation, ambient and indoor air exposure estimation, and ambient surface water exposure estimation."
                  DR. DANIEL SCHLENK:  Okay.  Our lead discussant for that is Dr. Blystone.
                  DR. SHERI BLYSTONE:  Yeah.  Thanks.  I'm going to apologize upfront that I'm probably not as organized as Dr. Cobb or Dr. Przybyla was.  So forgive me in advance for skipping around a little bit.  I'd also point out, like Dr. Doucette said, some of these things may be duplicative of what you've heard in previous comments as well.  But we'll try to keep that to a minimum or just mention them again as necessary.  With that being said, I'll just dive right in.  This is my comment.
                  Since there's a lot of talk about TRI data throughout this process, the risk evaluation process in general, and I'm always sort of amazed at the level of contortions that EPA goes through to try to figure out how to box that information for that facility.  It seems like there's an opportunity there in a very simplified, standardized way, maybe through the web.  You've already identified facilities through TRI that you could go and say, here's an opportunity to provide this additional clarifying information that we need on this chemical.
                  You can do that for the ones under review, for the ones you're thinking about reviewing, for the next priority, and have that in advance, whether you use that in the pre-screening or the screening or final risk evaluation.  That would keep you from having to guess, which seems to happen quite a bit on what that facility is doing with that chemical.
                  There has been talk a couple of times about data that may be available at the state, particularly through permitting for some of the larger facilitates and those reporting for TRI.  They probably have permits, and there's probably information there that could be used to help you clarify all of this information as well.  There's been talk about a need to validate the screening results versus actual monitoring data.  I think that was brought up yesterday by Dr. Doucette, something that could be useful and enhance the tool as it is, the approach.
                  From a reader perspective, if you look at the non-technical summary and the tables that EPA is putting out there to show the results of their assessment through this approach, it might be useful to put a little bit more detail in there about when they're saying, "additional risk was identified," what that was.  For instance, if it's 1,000 meters plus or 0 to a hundred meters or whatever that might be and how many facilities, that might be something that would be useful to the non-technical reader to try to help them understand what that risk might be.
                  I'm not sure that this has come up specifically yet, but it probably has.  In addition to validation and the sensitivity assessment, when you're changing the variables in this approach, like which ones are the ones that are most important that might help you key into what you would need to ask those facilities for is for additional clarifying information.  So that sensitivity analysis could be useful.
                  There was a comment that EPA proposed to identify occupational exposure scenarios based on CDR reporting, consumption codes, which are in turn derived from TRI data, conditions of use, sources of ambiguity, and errors in the tools to facilitate database crosswalks.  EPA should explain how it interprets conflicting information gaps, et cetera, so as to provide a conservative high estimate for exposure.  So some further explanation of that could be useful.
                  On page 21, EPA talks about the 10,000 meters for exposure assessment.  It seems to imply that EPA is considering the influence of multiple sources.  I think a couple of us had the impression that the approach actually was looking at where -- if you're looking at two sources, and you're drawing the circles, and there's overlap in those circles, that we were looking at that.  From what we heard yesterday, apparently, that's not true.  I think that's maybe something practical that could be added to the approach as it is.
                  If two of the facilitates do have overlapping exposures, then you can look at that as another potentially exposed subpopulation, for instance, and look at that exposure from both sources.
                  I think in the water side -- you may already be doing that -- looking for if they're discharging into the same body of water, that you're adding that information together.  If you're not, then perhaps you should be.
                  There was a comment that we have heard many opinions to the effect that the screening framework may identify sources as meaningful risks due to data limitations and modeling assumptions.  But the point of the screening tool is to identify protentional risks that may warrant further study.  Therefore, it's important to have a low probability of missing real risks.  It is more important to have a low probability of missing real risk than it is to exclude non-risks.
                  This commenter believed that the screening framework report makes that clear, that the output of the screening model is not intended to be interpreted as definitive findings of risk.  Since some people are still having questions about that, maybe there's some clarity that could be added there.
                  There was a comment that the document should provide a conceptual overview of resources and explain what data will be extracted, clearly identifying simplifying assumptions, for example, mapping each condition of use to occupational exposure scenario combination, from the initial risk assessment to one IFC code or TRI use/subuse, even if the facility reports multiple uses or subuses.
                  EPA should comment on sources of error or uncertainty in these other resources that may affect exposure calculations in the screening methodology.
                  There was a comment, and I've had this as well.  What happens when chemicals under review aren't on TRI?  What approach is EPA going to take then?  Right now, there's a heavy emphasis on TRI data.  So what happens if you're looking at chemicals that aren't on TRI and what all those other data sources might be using.  This particular commenter talked about maybe there's consulting reports or other facility-specific information that could be used by the Agency.
                  A very specific comment, that there was a sentence on page 19, lines 127 to 130, that seemed incoherent and that the Agency might want to take a look at that and clarify.
                  Also very specifically, on Table 3-1, there was a question. Does "benchmark" refer to benchmarks margin of exposure for the first two rows?  Is margin of exposure based on the NOAEL or the LOAEL in the third row?  Is this the benchmark probability of additional cancer?  Please clarify.
                  There was a comment, page 37, using 1.8 meters tall for receptors might be a bit tall for females or children.  Maybe there's some clarity or some adjustments that could be made to using that as a benchmark for the receptors.
                  Page 46, the lack of ambient NMP data in water is a glaring data gap that needs to be filled at locations near several point sources.  I think that's been brought up before as well.
                  I think this was also brought up by Dr. Kissel earlier.  It's unclear that dermal exposure will not pose significant risk relative to inhalation.  There's another commenter that supported that.
                  On the land-use side -- and this is on page 32, 33 -- we've got rural.  We've got urban, but what about suburban?  How should that be managed?  Perhaps there's an opportunity there.
                  This is specific to page 45, but the SACC established in previous reviews that, for many of the scenarios presented, air emissions could not be decoupled from the assessment of water as the concentrations emitted to air from multiple sources were predicted to be much higher and would cause portioning of volatile chemicals back into water as significant concentrations relative to the direct emissions of water.  I remember Dr. Cobb saying those comments many times.
                  There's also comments here about the hundred meters and that something nearer.  I think that may have been clarified earlier this morning.
                  On page 111, limit of detections, there was a question about or comments that those are not handled properly.  All values with the limited detection above ten must be included if half the limited detection is used for statistical thresholds.  Otherwise, all the data from these higher LODs should be excluded and that this was a serious loss.
                  For me personally, I also had struggled with the LOD.  I think I came at it from a different perspective.  It feels like the way the Agency handled how they are managing non-detects, if you will, and then using LODs needs some clarity.
                  Again, there's no assessment of partitioning from air to water, and this needs to be fixed.
                  Many of the exposure assessments, and therefore risk conclusions, depend on assumptions inputted into the various calculators and models.  The proposed methodology uses the most conservative assessments to be most protective of health, which is appropriate in a screening phase.  Additional modeling efforts, such as those done when no data is available, would help increase the confidence in the 2019 TRI data.  A threshold of action could be implemented.  That, if reached, could result in greater inquiries about characteristics into the AERMOD to ensure accurate information is being inputted.  This could depend on the population density in areas of greatest interest.
                  A similar approach could be taken for water release estimation, ambient and indoor air exposure, and ambient surface water estimation, as all conclusions depend heavily upon conservative input.  If a very high risk is detected, thresholds to be decided, that could result in further investigation of input to help improve the accuracy of the risk estimate.
                  Another comment about the Agency sustaining open and accessible relationships with the fenceline communities as a stakeholder to ensure methodologies are adapted and replaced as needed to protect public health.  This will reveal routes of exposure in realities not represented in Version 1.1.
                  Uncertainties and improvements to screening methods must not be used to delay protections by not closing the door on chemical risk classification.  The EPA can continue to pursue and utilize the best possible science.  The methodology must also be adaptable to the impacts of climate change release and dispersal.  Yearly averages may hide accidental releases and acute exposures on any given day.
                  Communities may not be exposed to the chemical at the same concentrations each day.  The AERMOD and IIOAC software used in Version 1 allow for analysis to include exposure to multiple facilities, which we talked about earlier.  The commenter recommended that EPA expand the application of this software in pursuit of the best possible science.
                  Also, comments, again, on cumulative impacts has been brought up a few times already. The commenter also specifically called out the comments by the National Tribal Toxics Council that note that the use of geospatial analysis may underestimate the exposure of tribal and indigenous communities.  The commenter supported those comments.
                  Again, talking about the limiting of the approach to only air and surface water releases, compounds like TCE and PCE groundwater contamination and vapor intrusions are likely important pathways into fenceline and other communities.  Other potential exposure routes, such as food chain contamination, could also be important for some chemicals.
                  A detailed step-by-step example calculation of the estimated fenceline air and water concentrations would be useful for interested parties attempting to reproduce the calculations.
                  Another comment in support of sensitivity analysis so that the reader can better understand how variabilities in input data impact the predicted concentrations at the fenceline.
                  As mentioned in previous SACC discussions, better highlight or emphasize model limitations, such as the lack of degradation and volatilization processes in E-FAST and discuss if the model limitations result in appropriately conservative estimated concentration.  It was also brought up, I believe, yesterday and then maybe earlier today, maybe by me, that you could use the monitoring data to validate the results of this approach and that there might be sources of those data available.
                  There's some links here that we will provide.  The Agency could illustrate how this draft's screening approach could be expanded to consider the impacts of multiple chemical exposures, releases from multiple industries in the same location, co-contaminants, et cetera.
                  Back to the 10,000-meter static buffer, it may be helpful to consider circumstances under which available data will support an alternative to the assumption of a 10,000-meter buffer to instead be something reflective of the environmental fate and transport characteristics of the contaminant's behavior in the local setting.  If a pollutant is expected to be dispersed farther than 10,000 meters, then the definition of the fenceline community with respect to that contaminant seems like it should be extended.
                  Again, communities making use of the receiving water bodies for a drinking water source, accounting to the extent to which populations rely on public water supplies versus alternative water sources, like wells, is an important data point.  There is limited spatial data available on this from the 1990 census, with updates available from the U.S. Geological Survey, for spatial estimates in different years of the number of persons relying on private wells, benefit-to-risk assessment to consider whether drinking water is largely consumed from private wells near a receiving water body.
                  Additional site-specific characteristics, like three-dimensional groundwater or hydrological dynamics, would be pertinent if this is sociologically a zone where human populations are reliant on the groundwater as a drinking-water source.
                  That is it for what I've received.  My apologies to anyone who sent me stuff that I didn't report correctly.  I'm sure you can correct me now.  Thank you.
                  DR. DANIEL SCHLENK:  Great.  Okay.  Let's move down the associate discussant list.  Dr. Przybyla.  I'm not hearing you.  Are you muted?  Dr. Przybyla, do you have any other comments?  Okay.  Still not hearing you if you're muted.
                  DR. ALAA KAMEL:  She said she is having connection errors, and she's trying to log back into the meeting.
                  DR. DANIEL SCHLENK:  Okay.  We'll get back to her then.  Thanks, Alaa.  Next on the list, then, would be Dr. Calder.
                  DR. RYAN CALDER:  My comments are reflected.  Thanks.
                  DR. DANIEL SCHLENK:  Fabulous.  Dr. Unseld.
                  DR. MONICA UNSELD:  I have nothing to add.
                  DR. DANIEL SCHLENK:  And Dr. Doucette.
                  DR. WILLIAM DOUCETTE:  Yeah.  I thought Dr. Blystone did a great job at summarizing the comments.  One that I've just sent her -- and I think it's been discussed before -- any screening efforts should incorporate background VOC concentrations from consumer products, building materials, et cetera, in any indoor air assessment.  So that adds, potentially, an additional factor to the exposure concentration since, for most VOCs, they're typically five to ten times higher indoor than outdoor.  Thank you.
                  DR. DANIEL SCHLENK:  Okay.  Thanks.  Dr. Przybyla, are you back?
                  DR. JENNIFER PRZYBYLA:  Apologies.  I had some network issues.
                  DR. DANIEL SCHLENK:  No worries.
                  DR. JENNIFER PRZYBYLA:  I have no further comments.
                  DR. DANIEL SCHLENK:  Okay.  Thanks.  Okay, with that, we'll open it up to the rest of the Committee.  Dr. Reiss.
                  DR. RICK REISS:  This is Dr. Reiss.  This is my first experience on the Panel.  I've been on the other side of these.  There's a lot of great comments.  I also feel like it's easy to make a lot of these suggestions and maybe a little bit hard for EPA to implement many of them.
                  I have experience in dispersion modeling and dealing with emissions data.  I think we just have to acknowledge what EPA is trying to do here is really, really hard.  I mean, there are hundreds of HAPs, hazardous air pollutants.  There are tens of thousands of facilities.  The complexity here is just massive.  I might have made a simpler screening methodology.  I might've also tried to use the NEI to get the real stock data.
                  EPA did what they thought was right here.  While it's complex, it's dealing with a massively complex and challenging problem.  Hopefully, we can distill this down to a few good items that we can recommend to make this better.
                  Just an acknowledgment by EPA that some of this stuff is not there yet, in terms of other pathways, and that there's going to be a 2.0.  This is tailored toward the specific properties of the three chemicals that are in here.  I don't know.  I think that, just as an overarching comment, that strikes me.
                  I also think, given all that, the other overarching comment is that this is a screening approach.  I think EPA should keep to their general paradigm for a screening approach is that refinements need to be possible before you move onto a rule or something like that.  We're being good at pointing out all the different uncertainties here.  Of course, there are a lot of uncertainties.
                  In terms of whether this is conservative or not is really one of the rubs, the real questions here.  There's reason to think because there are some pathways that are not included, you have some questions there.  Like I said, I'm the dispersion modeling expertise.  Just the stack height assumption alone, I think, adds a tremendous amount of conservatism to this.
                  Just in terms of whether it's conservative or not conservative, which is what a screening-level approach needs to be, I think it's conservative.  But, of course, that's my professional judgment.  It's just professional judgment.  If there's some kind of methodological way that that could be demonstrated with an available dataset, I think that that would strengthen this process.  Those are my comments.
                  DR. DANIEL SCHLENK:  Thanks, Rick.  Appreciate that.  Dr. Davies.
                  DR. HOLLY DAVIES:  Hi, again.  Thanks to Dr. Blystone for her list.  We've talked about the overlap.  This topic has been mentioned before; it will be mentioned again.  But I think it is important to include PBTs in how this will be because none of these chemicals chosen are PBTs.  Some of the first ten -- I guess I'm thinking about HPCD.  In the future, this will be applied to chemicals that are persistent, bioaccumulative, so it's important to include that and how to include that.
                  I was really interested in what Dr. Reiss just said, interested in his simpler ideas of how to get this down.  Sheri also mentioned this, the importance of "is this conservative?"  I think that's agreed that that's an important question for the Committee.
                  DR. DANIEL SCHLENK:  Yeah.  That definitely seems to be -- how we are going to define conservatism, basically, seems to be a fairly -- something where consensus is a little bit lacking, I would say, at this point.  Dr. Doucette.
                  DR. WILLIAM DOUCETTE:  Just one additional point, it's important also to remember that the chemicals that this screening approach is being applied to have a history of environmental releases.  I realize the challenge -- and this was brought up in a previous speaker -- the challenges that EPA faces with all the multiple pathways.  But to ignore a pathway for TCE, PCE, or even 1-BP through vapor intrusion seems -- since there's so much history and so many case-study examples of that, that seems to be a big hole in the approach.
                  So I think because these chemicals have such a history, that helps us decide what pathways likely are going to be important or have been important in the past.  And to ignore that, I think, is an issue.  We can use that information to make judgments on which pathways are likely to be most relevant for these specific compounds.  Thank you.
                  DR. DANIEL SCHLENK:  Great.  Thanks, Bill.  Dr. Kissel.
                  DR. JOHN KISSEL:  Apropos my comments on Question 2, in under the Question 3 rubric, I would add the specific references to the Regional Screening Level online calculator to the computer exposure model and to RAGS Part E, all of which have methodologies that are not addressed here.
                  DR. DANIEL SCHLENK:  Okay.  Again, yeah, please get your information into Sheri for that.  Thanks.  Any other comments from the Committee on Question 3?  Dr. Li.
                  DR. LI LI:  Yeah.  I just want to add some about my two cents.  Because we are talking about how to make these documents practical and easily applicable to everybody, so maybe we can do two things.  The first is to keep everything comprehensive.  For example, we can try to include as many exposure pathways as possible because some exposure pathways may be important for some chemicals, with chemicals with some physical/chemical property.  At the same time, some exposure pathway may be important for some subgroup population.
                  For example, food chain bioaccumulation contamination may be important for some people who rely on locally produced food, or for example, the mouth immediate ingestion.  That is, you touch a dirty surface, the ground, and then put your hands into your mouth, may be important for some in the fenceline communities.  This is why we have to keep in mind that all exposure routes would matter in terms of the total exposure.  So that's my first thought.
                  The other thought is can we try to keep everything simple?  For example, at this moment, we use a AERMOD for the full-screen level, for the air pollutions.  But I think that the model is too complicated.  You have to rely on a lot of site-specific data to run the model, which is not available to many local communities or local authorities.  If the fenceline communities want to do the simulation for themselves by themselves, this is no way to do.
                  Maybe we can get rid of some very complicated, very sophisticated approach and just keep it simple.  So I'm not sure whether it is okay to keep this site-specific, or we just go back to the generic simulation, for example, for air pollutant.  Just the two cents, keep it comprehensive and keep it simple.  Yeah.  That's all.
                  DR. DANIEL SCHLENK:  Okay.  Thank you, Dr. Li.  I think you might have some discussion on that comment.  Dr. Unseld.
                  DR. MONICA UNSELD:  Yeah.  I agree with Dr. Li.  I just thought, reflecting on the repetitiveness of the responses to the charge questions, if there have been previous SACC comment or recommendations, they could be used to simplify this.  I think they should be used to simplify this because it sounds like there may have been some things in the past that could make this a little easier.  We have to do what we can do now to protect the public health, but we also need to keep in mind that there's a long game here where we need to, overall, just improve the entire process.
                  I think we just need to be cognizant of what's on the long term, building up capacity, independent monitoring, all of the things that can make the entire process, screening process, regulatory process, more effective, but at the same time making sure that it makes sense and that it's reliable enough to do something now.  If there are things on record that can do that, I hope the Agency does that.  Monica Unseld.
                  DR. DANIEL SCHLENK:  Thank you.  Dr. Gribble.
                  DR. MATTHEW GRIBBLE:  Hi, this is Dr. Gribble, a temporary member of the SACC from the University of Alabama Birmingham.  I would slightly disagree with Dr. Unseld and Dr. Li on this about the importance or lack of importance of complexity.  So many of my comments are geared towards the opinion that incorporating additional exposure pathways and incorporating potentially chemical site-specific information and, if you're going to add groundwater as an exposure pathway, three-dimensional hydrological modeling would be value added for screening community risks in a comprehensive way.
                  I think that a question I have is the onus of doing this analysis.  It's been assumed that this would be done by EPA agency staff with limited EPA agency staff resources.  Potentially, this could be a polluter-pays situation where sites seeking to demonstrate a lack of excess hazard from discharge of a known toxic chemical could be responsible for demonstrating through compliant analysis that they were not creating excess risk for the community.
                  It was also suggested that fenceline communities themselves wouldn't have the bandwidth to do this.  I don't know that it should be the responsibility of a fenceline community that often will have limited resources to do this screening assessment or contest the EPA screening assessment through their own analysis.
                  So I was wondering if it was something that the SACC could consider for its recommendations about who would be responsible for this because, if there is an army of environmental consultants out there doing this kind of assessment, it might be more technical and feasible to do a more comprehensive assessment than if it was Agency staff doing it and if it was community doing it.  I just thought that the who's doing what of this might be something we would want to encourage EPA to think about.
                  DR. DANIEL SCHLENK:  Okay.  Thanks.  Dr. Johnson.
                  DR. MARK JOHNSON:  Thank you.  Yeah, I was just kind of thinking out loud and considering some of the previous comments made regarding simplicity, the fact that this is a screening approach.  I'm wondering if there would be value in the EPA doing a sort of sensitivity analysis thinking about which factors have the greatest influence on predicting risk or predicting hazard.  One example may be dermal exposures through swimming.  I wonder.  We've heard some criticisms of maybe the use of the permeability coefficients.
                  I'm wondering, really, how much does that affect the overall exposure and the overall characterization of risk?  Again, just to paraphrase, I think there may be some value in doing a sensitivity analysis to see which factors attribute mostly greatly to the final hazard estimate.
                  DR. DANIEL SCHLENK:  Okie doke.  Thank you.  Sheri.
                  DR. SHERI BLYSTONE:  Yeah.  Just reacting a little bit to a couple things.  The site-specific data is going to be important somewhere down the line.  Ideally, we're doing some tiered screening process that eliminates and focuses our resources on things that are of the most concern.  That's what everybody, I think, would agree we're looking for.  We may disagree on the specifics of that, but the process is that we're looking to focus resources there.  But when you get to that higher-level evaluation, you're going to need better data.  That includes the specifics on the site.