As the researcher in charge of the Hg studies on children in the Faroe Islands since 1985 I want to correct this statement. The Faroese children are not exposed to methylmercury by eating fish. They are exposed to Hg by the traditional consumption of pilot whale meat. Fish normally consumed in the Faroes, e. g. Cod and haddock, are low in Hg and do not, to my opinion constitute any threat to the health of the Faroese children. In the contrary the fish consumption most likely is beneficial to their health.

The Faroese authorities in 1998 recommended women who plan to become pregnant within months, pregnant women, and nursing women to abstain from eating pilot whale meat. The Hg concentration in the blood of pregnant women has declined dramatically since and are now below the US EPA limit.

Yours sincerely, Pal Weihe, Chief Physician The commenter asks, how can EPA or the National Research Council seriously cling to the Faroe study for its RfD for fish consumption when the lead author states the study has nothing to do with MeHg in fish, but only in whale meat? How can Dr. Grandjean claim associations between IQ levels in Faroese children and fish consumption ( see further discussion under comment Q below) when Dr. Weihe reports that those children ( a) are not exposed to MeHg by eating fish, ( b) are exposed to no health threat from fish, and ( c) actually benefit from maternal fish consumption?

The commenter urges EPA to discontinue relying on the very weak ( and inappropriate) scientific foundation to base its claim of negative impacts on children neurodevelopments using the results of the inferior Faroe children study.

The commenter further documents here additional evidence of the extremism or ultraprecautionary nature of the current EPA RfD for MeHg.

First, it is clear from the ethical guidelines established by the Institutional Review Board of the National Center for Health Statistics of the CDC that approved the NHANES study that 9 288 cautions are issued to NHANES participants only if their total hair Hg levels are above 15 ppm or total blood Hg above 200 ppb ( McDowell et. al., 2004, Environmental Health Perspectives, in press, available online May 27, 2004). The ultra precaution by EPA is connected to its RfD which considers a blood Hg level to be safe only at levels below 5.8 ppb, which is dramatically lower than the ethical guideline established by the Institutional Review Board of CDC.

Second, it is obvious from the latest results of the Japanese hair Hg measurements for 8665 individuals collected in 10 different locations over 1999 to 2002 by Yasutake et al. ( 2004, Journal of Health Science, vol. 50 ( 2), 120 125) that the overwhelming majority of the Japanese population, i. e., 87 percent, has hair mercury levels exceeding the mercury" safety" level set by EPA's RfD. Since there is no detectable epidemics of any defective mental capability of both the Japanese adult and children populations, the commenter suggested that such reality confirms the ultra precautionary nature of the current EPA RfD level for MeHg, and conclude that the actual levels of concern from MeHg exposure occurs at much higher levels ( see for example, various values identified in Figure L1) than an the RfD value of 5.8 ppb in blood Hg adopted by EPA.

Response:

EPA acknowledges that there are complexities, including a variety of potential confounders, that must be considered in relation to potential cardiovascular mortality linked to methylmercury exposure. For additional discussion of this endpoint, see Appendix D.

Comment:

One commenter ( OAR 2002 0056 5423) believes that this particular statement by EPA is both confusing and misleading. The statement all by itself appears contradictory to what was stated in comment ( O) that EPA's RfD was derived from a single neurodevelopmental endpoint.

In addition, the commenter believes that any reference to the NRC ( 2000) report, Toxicological Effects of Methylmercury, about the review and assessment of these three epidemiological studies would be more complete in noting that:

" The committee concludes that there do not appear to be any serious flaws in the design and conduct of the Seychelles, Faroe Islands, and New Zealand studies that would preclude their use in a risk assessment. However, because there is a large body of scientific evidence showing adverse neurodevelopmental effects [ unfortunately, the NRC did not provide any precise citation for such evidence] ... the committee concludes that an RfD should not be derived from a study, such as the Seychelles study, that did not observe an association with MeHg." ( p. 6)

Therefore, the commenter concludes that the high quality results from the Seychelles study ( with additional assessment noted below) were ignored by NRC ( 2000) not for any scientifically defensible reasons, but because of a direct bias to recommend only results that show evidence for " adverse neurodevelopmental effects." This situation is truly unfortunate because it 9 289 is relatively well known that the results of the Faroe Island study had been contaminated by simultaneous exposures to other toxic chemicals like PCBs and DDT.

A post NRC ( 2000) analysis by Dourson et al. ( 2001, Neurotoxicology, vol. 22, 677 689) recommended that " The Faroe Islands data are from exposures to a mixture of chemicals. The Seychelles Island data are from exposures to primarily one chemical, MeHg.... We would... encourage EPA to use the Seychelles Island data as the basis of its MeHg RfD."

The commenter believes that this is why it is scientifically appropriate to challenge the biased conclusions of NRC ( 2000) and hence EPA's basis for its MeHg RfD. The Seychelles Island results are clearly superior for deriving RfD exposure to MeHg for the U. S. population. This is so simply because that study is without toxic confounders and the Seychelles Island mothers consumed ocean fish containing MeHg concentrations comparable to those consumed by the general U. S. population.

In contrast to the Faroe Island study, the Seychelles Child Development Study ( SCDS), " was specifically designed to test the validity of [ the] hypothesis [ of adverse neurodevelopmental effects] in a well nourished population exposed to MeHg only from high consumption of unpolluted ocean fish." The research authors recently concluded:

"[ SCDS] longitudinal assessment at 9 years of age indicates no detectable adverse effects in a population consuming large quantities of a wide variety of ocean fish. These results are consistent with our earlier findings in the same children examined at 6, 19, 29 and 66 months of age. In Seychelles, fetal exposure was continuous through frequent consumption of ocean fish containing concentrations of MeHg comparable to those consumed by the general population in the USA. We recorded effects from covariates known to affect child development, but did not find an association with prenatal mercury" ( p. 1692 of Myers et al., 2003, The Lancet, vol. 361, 1686 1692).

Constantine Lyketsos of the John Hopkins Hospital ( 2003, Lancet, vol. 361, p. 1668) in offering a professional overview on the implications of the Seychelles study concluded:

" On balance, the existing evidence suggests that methyl mercury exposure from fish consumption during pregnancy, of the level seen in most parts of the world, does not have measurable cognitive or behavioral effects in later childhood. This conclusion is especially true against the background of the several other variables that affect cognitive behavioral development. The positive findings from the Faeroe Islands and New Zealand studies may be related to the fact that pilot whale blubber and shark muscle contain 5 7 times the concentrations of methyl mercury than the fish consumed in the Seychelles. While higher concentrations in seafood do not necessarily lead to higher levels in maternal hair, consumption of much larger boluses by the mother could lead to greater difficulty on the part of the developing fetus to detoxify the mercury by natural mechanisms, as Meyers and 9 290 colleagues propose. Whatever the answer, the discrepant findings from the various studies need explaining. Whilst there is always an issue of power to detect an effect in a study reporting null findings, this is not likely to be the case in the Seychelles study with the sample size involved. If there is subtle association that could only have been detected in a much larger sample or through the use of more sensitive tests, it can reasonably be argued that the effect would be small enough to be essentially meaningless from the practical point of view. For now, there is no reason for pregnant women to reduce fish consumption below current levels, which are probably safe."

Response:

In deriving the reference dose for methylmercury, EPA relied on an integrated analysis involving three studies. These longitudinal, developmental studies were conducted in the Seychelles Islands, the Faroe Islands, and New Zealand. The Seychelles study yielded scant evidence of impairment related to in utero methylmercury exposure, whereas the other two studies found dose related effects on a number of neuropsychological endpoints. In the assessment developed for the RfD, emphasis is placed on the results of the Faroe Islands study, the larger of the two studies that identified methylmercury related developmental neurotoxicity. Supporting evidence from the New Zealand study provides assurance that choosing this focus is the appropriate strategy for protecting public health. Conclusions from the National Research Council review of methylmercury support this use of the Faroes Island study and disagree with the suggestion of a role for PCBs in the neurological effects observed ( NRC. 2000. Toxicological Effects of Methylmercury. National Academy Press.), saying that " The committee concludes that there do not appear to be any serious flaws in the design and conduct of the Seychelles Islands, Faroe Islands, and New Zealand studies that would preclude their use in a risk assessment."

The Agency's derivation of the RfD also followed the National Research Council recommendation for an overall composite uncertainty factor of no less than 10.

In summary, the Agency's overall confidence in this RfD assessment is high. Three high quality epidemiological studies published since the last derivation of the oral RfD in 1995, have been included in the analysis. Two of the studies ( Faroe Islands, New Zealand) reported effects on a number of neuropsychological endpoints, whereas the third ( Seychelles Islands) reported no effects related to in utero exposure to methylmercury. Benchmark dose analysis of a number of endpoints from both the New Zealand and Faroe Islands study converged on an RfD of 0.1 µ g/ kg day, as did the integrative analysis combining all three studies. Although there was coexposure to PCBs in the Faroe Islands study, statistical analysis indicated that the effects of PCBs and methylmercury were independent. Moreover, benchmark dose analysis of the endpoints that were significantly associated with methylmercury yielded RfDs that were approximately the same when corrected for PCBs. The same was true when the analysis was or based on the subset of the cohort in the lowest tertile with respect to PCB levels, as compared 9 291 with the full cohort. These findings provide further evidence that the identified effects are in fact the result of methylmercury exposure.

Comment:

One commenter ( OAR 2002 0056 5423) notes that the primary author the Faroe Island study, Dr. Philippe Grandjean, was found to have admitted in the May 20, 2002 Mercury Forum held at Mobile, Alabama ( http:// www. masgc. org/ mercury/) that " In conclusion, the commenter had obtained evidence of subtle adverse effects on neurobehavioral functions, blood pressure, and growth. At age 7 years, a doubling of the Hg exposure corresponds to a developmental delay of up to 2 months. Although IQ tests were not done, such delays would be comparable to a loss of about 1.5 IQ points."

Another relevant notice is the statement in Dr. Grandjean's written testimony at the Mercury MACT Rule Hearing at Maine State House on March 1, 2004, that " Even though the children that the commenter examined were all basically normal, we have documented detectable deficits that appear to be permanent." CSPP takes the statement to suggest that Faroese children are essentially all normal with normal functioning capability despite the permanent " detectable deficits" of the sort described by Grandjean.

Finally, it was also clear that the cued Boston Naming Test conducted by the Faroe study does not constitute a proper IQ test.

The commenter believes that, in short, Dr. Grandjean's statements are contradictory at best. They would not hold up in a rigorous scientific evaluation by other experts or his peers. They should not go unchallenged by EPA either, especially as his raw data are not transparent.

But the commenter notes that the really relevant question to assessing the statement in ( Q) is whether if any or all of these reputed neurodevelopmental outcomes and tests can be shown to be related to MeHg exposure. In that regard, it is important to consider that for a total 17 neuropsychological tests conducted by the Faroe study to search for associations with prenatal exposure to MeHg, only 3 tests ( both the cured and uncured Boston Naming Tests and the socalled Neurobehavioral Evaluation System Continuous Performance Test) yielded statistically significant correlations only if the Faroe researcher considers maternal cord blood as an independent predictor ( Budd Jorgensen et. al., 2003, Environmetrics, vol. 14, 105 120). The statistical correlation for the same 3 test scores dramatically turned insignificant or only marginally significant when the measured maternal hair Hg is adopted as the independent variable instead.

Dr. Gary Myers, one of the main authors of the Seychelles Island Child Development Study, makes the point that even the 3 statistical associations found by the Faroe Island study are a lot less impressive than one is lead to think if one properly weighs in the statistical odds. In a July 29, 2003' s testimony to the Senate Environment and Public Work Committee, Myers noted:

" Through 107 months ( 9 years) and over 57 primary endpoints, the [ Seychelles 9 292 Island] study has found only three statistical associations with prenatal MeHg exposure. One of these associations was adverse, one was beneficial and one was indeterminate. These results might be expected to occur by chance and do not support the hypothesis that adverse developmental effects result from prenatal MeHg exposure in the range commonly achieved by consuming large amounts of fish. The test results do show associations with factors known to affect child development such as maternal IQ and home environment so there is evidence that the tests are functioning well [ i. e., the Seychelles Island Child Development Study shows evidence for a high degree of internal consistency]."

Myer concluded in his senate testimony:

" We do not believe that there is presently good scientific evidence that moderate fish consumption is harmful to the fetus. However, fish is an important source of protein in many countries and large numbers of mothers around the world rely on fish for proper nutrition. Good maternal nutrition is essential to the baby's health. Additionally, there is increasing evidence that the nutrients in fish are important for brain development and perhaps for cardiac and brain function in older individuals."

The commenter believes that in the context of positive or negative brain development from trace Hg fish consumption, real world data trumps modeling or alarmist assertions. For example, in the latest data from the Trends in International Mathematics and Science Study, students ( grade 4 and 8) in Asia continued to excel. Singapore, Hong Kong, Japan and Korea were among the top performers in over 50 countries participating. The U. S. placed well below these countries. As EPA noted, Asians are among the largest fish consuming peoples in the world. If alarming neuropsychological and neurodevelopmental deficits from prenatal MeHg exposure through fish consumption ( as interpreted by Dr. Grandjean in the Faroe children study) are correct, then these Asian students are the very populations that should be evidencing an epidemic in low IQ, instead of topping the curve on international standardized math and science tests.

Response:

As many factors influence performance, relative rankings on the International Mathematics and Science Study are not indicative of the impact of MeHG. As stated above, in deriving the reference dose for methylmercury, EPA relied on an integrated analysis involving three studies. These longitudinal, developmental studies were conducted in the Seychelles Islands, the Faroe Islands, and New Zealand. The Agency's overall confidence in this RfD assessment is high. The US Government also emphasizes that fish and shellfish are an important part of a healthy diet for women and young children; and that women and young children should include fish or shellfish in their diets due to the many nutritional benefits. Recommendations for selecting and eating fish or shellfish are made by EPA and FDA. These recommendations, if followed, should enable women and young children to receive the benefits of eating fish and shellfish and, at the same time, they can be confident that they have minimized their exposure to the harmful effects of mercury. 9 293 Comment:

The commenter ( OAR 2002 0056 5460) stated that in response to EPA's request for feedback on the comments submitted by the Electric Power Research Institute (" PERI") and the UARG ( see 69 Fed. Reg. at 69,873 [ 2nd Column]), the commenter noted that those comments suffer from profound factual, logical and legal flaws. The commenter further stated that, accordingly, EPA need not attempt to respond to every last technical assertion advanced by those commenters. The commenter added that listed below are two illustrative examples of threshold, overarching problems in the PERI and UARG comments.

The commenter stated that, first, in a strained attempt to argue that domestic power plants do not contribute to Hg hot spots, PERI writes that a particular " geographic location" is " utility influenced" only if 50 percent or more of the Hg depositing there stems from utilities ( See OAR 2002 0056 2578 [" PERI Comments"]). But, the commenter stated, PERI provides no reason to adopt its definition of " utility influenced" and no such reason exists. The commenter added that, plainly, utilities can contribute less than 50 percent of the Hg in a given location and still influence that location. See, e. g., William L. Prosser, W. Page Keeton, et al., The Law of Torts § 52 ( 5th ed. 1984) (" Pollution of a stream to even a slight extent becomes unreasonable when similar pollution by others makes the condition of the stream approach the danger point."); U. S. v. Alcan Aluminum Corp., 315 F. 3d 179, 187 ( 2d Cir. 2003) ( explaining that harm that is minimal on its own may be significant when combined with other harms). The commenter stated that, in addition, EPRI's argument that domestic power plants do not cause hot spots cannot be reconciled with its simultaneous assertion that the " state of the science is too imprecise" to measure the significance of reduced Hg emissions ( see also OAR 2002 0056 2922 ( UARG Comments)). The commenter further stated that PERI is simultaneously claiming that EPA cannot measure the consequences of reducing Hg emissions and that power plants are only a small part of the Hg problem. The commenter stated that PERI cannot have it both ways: Either the significance of power plant emissions can be measured with precision, or it cannot be. The commenter stated that , in all events, however, EPA has already determined that Hg power plant emissions require regulation pursuant to Section 112, and no factual or legal basis exists to undo that decision now.

Response:

EPA has examined the commenter's concerns in context of the final rulemaking. EPA is finalizing a cap and trade approach under section 111. EPA has addressed the hot spots issue in the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112 Notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket. 9 294 Comment:

The commenter ( OAR 2002 0056 5460) states that with regard to step five of EPA's proposed revised benefits assessment methodology, EPA has not adequately explained several aspects of its focus on IQ as the neurodevelopmental endpoint. See 69 Fed. Reg. at 69,878. The commenter further stated that, for example, EPA has not adequately explained why it is not also evaluating other neurodevelopmental endpoints. The commenter added that it has likewise failed to explain how it will use the Faroe Islands and Seychelles Islands studies to measure IQ decrements, especially given its admission that those studies did not conduct sufficient tests to estimate IQ.

Response:

As part of its analysis of the final rule, EPA has estimated some of the health benefits of reducing Hg from utilities. At this time EPA is only able to provide quantative estimates of the benefits of reducing neurological impacts of exposure to MeHg for a portion of the U. S. population. Please refer to Chapter 2 of the RIA for a description of approach and rationale.

Comment:

One commenter ( OAR 2002 0056 5497) stated that the NODA indicated that an analysis currently being performed by EPA and Harvard researchers will be peer reviewed and placed in the docket " as soon as it is available." The commenter questions whether EPA can even complete the detailed analysis described in Step 5 by March 15, 2005   the date on which EPA says it will issue a final CAMR   much less having it peer reviewed. The commenter further doubts whether interested parties will have a meaningful opportunity to review and comment on this analysis before a final rule is issued. This lack of a meaningful comment opportunity is of particular concern because this last minute analysis appears to be designed to overstate whatever health effects may result from Hg emissions from coal fired power plants.

The commenter asked why was this detailed health effects assessment not included as part of the Hg or utility studies? Why was it not presented as part of the proposed rulemaking package? A number of questions in this part of the NODA involve human health assumptions and approaches that are significantly different than those recommended by the National Academy of Science ( NAS) and those used by EPA in establishing a Reference Dose ( RID) for MeHg. Why were those new approaches not vetted as part of the Integrated Risk Information System ( IRIS) database process or in some broader forum?

The commenter's earlier comments contained a series of criticisms about EPA's RID process. Those comments expressed concerns about how EPA had manipulated assumptions to produce a reference dose that was lower than ones produced by other federal or international organizations. Many of the questions posed by EPA in the NODA seem aimed at further manipulating available information to find even lower levels of cause and effect relationships. 9 295 Question a: The focus of neurodevelopmental health of children The neurodevelopmental health of children should remain the focus of MeHg health effects. Other health endpoints such as cardiovascular effects should not be used in place of neurodevelopmental effects on children. The cardiovascular studies cited by EPA and other commenters raise many scientific questions. The cardiovascular studies have yielded, contradictory results. The Finnish study by Salonen that first raised concerns about the linkage between MeHg exposure and cardiovascular disease has many problems. These problems are discussed in detail in EPRI's NODA comments and comments submitted by the Center for Science and Public Policy. Briefly, Salonen's conclusions rest on relative risk relationships that are so low as to be questionable whether they really exist. In addition, coronary heart disease has multiple risk factors that cannot be completely controlled in a study design   the eastern Finland study group had high intake of meat, fish and saturated animal fat and a low intake of vitamins and other vegetable derived antioxidants. Finally, follow up studies of this Finnish population were greatly separated in time, casting further doubts on Salonen's findings.

The ongoing National Health and Nutrition Examination Study (" NHANES") study has failed to find a relationship between blood Hg concentrations and blood pressure, raising further questions about the relationship between MeHg exposures and cardiovascular disease. Therefore, the focus of any benefits analysis should remain on the neurodevelopmental health of children, until other health endpoints have been studied to the extent of the neurodevelopmental ones and those other endpoints are shown to be more sensitive than the neurodevelopmental ones.

Question b: The selection of IQ as an endpoint for quantification of neurodevelopmental effects and whether it is an appropriate endpoint for benefits analysis for reduced exposure to MeHg There is no indication that IQ is a good measure of potential impacts of prenatal MeHg exposure. The Seychelles and New Zealand studies did not find statistically significant associations between MeHg exposures and IQ reductions. Testing in the Faroes did not include measures of I Q. Indeed, there was no consensus among the three tests in the design phase that IQ was an important domain that was likely to be affected by MeHg exposure.

As EPRI's NODA comments explain in greater detail, IQ tests are not a validated measure of brain function. Furthermore, the lack of a global IQ measure can mask subtle changes in a specific domain.

Quite simply, the fact that IQ differences can be monetized in a benefits analysis does not make IQ a good measure of MeHg exposure.

Question c: Whether other neurodevelopmental effects can be quantified and are amenable to economic valuation At this time, The commenter does not offer a response to this question. 9 296 Question d: Whether, and if so how, data from the Faroes Islands, New Zealand, and Seychelles Islands studies can be integrated for purposes of a benefits assessment EPRI's NODA comments explain in great detail why integrating the Faroes, Seychelles and New Zealand results into a meta analysis is not scientifically sound. The commenter agreed with those comments. Factors that hinder integration include: different study populations that have cultural differences and different possible confounders, different testing ages among the study subjects, different diets ( the diets in the Seychelles and New Zealand were based largely fish consumption while the diet in the Faroes relied heavily on consumption of pilot whale), differences in exposure measurements ( the Faroes researchers used cord blood while the Seychelles and New Zealand researchers used hair samples), different outcome tests were used in each study, and differences in the covariates measured and included in multivariate analyses. Furthermore, there is no consistent pattern of significant results across studies. If IQ is used as the endpoint in the meta analysis, then a surrogate needs to be found for the Faroes results. The choice of any surrogate is problematic. For all these reasons, the lack of comparability among the three studies precludes combining their results in a meta analysis that could be used in a benefits analysis.

Question e: The choice of the K= 1 model for estimating the relationship between exposure and IQ and practical alternatives to that approach Assuming a K= 1 model is inconsistent with the recommendation of the NAS panel which favored a K 1 model. 87 A K= 1 assumption is also contrary to the results of two statistical analyses of the Seychelles results that are discussed in EPRI's NODA comments. These analyses indicate non linear associations between MeHg exposures and test performance. Thus, the choice of K= 1 model is not yet warranted.

Question f: The appropriateness and consistency of using a linear dose response model given the RfD established by EPA in 2001 ( reflecting NAS review in 2000), which assumes a threshold dose below which there is not likely to be an appreciable risk of deleterious effects during a lifetime In many ways, this question answers itself. A linear dose response model, that presumably passes through the zero point, is inconsistent with the RID that EPA has established for MeHg that assumes a threshold effect level. A linear model is also inconsistent with similar values that have been used by the Agency for Toxic Substances and Disease Registry ( ATSDR) and the WHO in their development of RID analogues. As the question notes, the NAS panel, whose report EPA relies on to support its RID, also viewed a threshold model as most appropriate for MeHg.

Unfortunately, the NODA offers scant explanation of why EPA now believes that switching to a linear model is appropriate. EPA offers no explanation as to why it may now, interpret the Faroes, Seychelles and New Zealand results as supporting a linear model. The NODA simply recites, without explanation, that a group of Harvard researchers will likely assume 9 297 a linear dose response relationship." The only other hint in the NODA as to why EPA may be considering using a linear model is the " practicality" of using a linear model because it " would allow [ EPA] to estimate benefits of reductions in exposure due to power plants without a complete assessment of the other sources of exposure." While a linear model may ease the Agency's burden, it is nonsensical to use such a model if it does not comport with actual scientific observation. Indeed, a linear model will vastly overstate the benefits attributed to limiting Hg emissions from coal fired power plants. EPA should not change from its RID threshold model without a public review and comment process that at least rivals the one it provided when it last revised its MeHg RID. Merely mentioning that the Agency is considering using a model without a detailed explanation why hardly suffices as adequate notice.

Response:

EPA does not have access to the study data for the three key studies. The only data available to EPA are regression coefficients and other statistics that have been published by the study investigators. Therefore, EPA is not able to conduct any modeling that would examine alternative shapes to the dose response relationship, including non linear models. EPA's analysis involves a statistical integration of linear dose response functions that have been reported by the study investigators. We believe that use of a linear function, in conjunction with using a nonthreshold model, in our analysis is well justified by the following considerations: 1) The National Research Council's 2000 report on methylmercury used linear model results for deriving benchmark doses, and cautioned against use of supralinear models; 2) the Faroe Islands research team reported that K power models ( with the NRC recommended constraint of K > 1, i. e., with supralinearity excluded) fit best with the linear specification, i. e., K = 1; 3) linear model results are available for IQ for all three studies, and no non linear model results are available from the three studies ( except for Faroes log model), and raw data are not available to us for conducting analysis of dose response shape or other issues; and 4) the lowest exposures in the Faroe Islands study overlap with U. S. exposure range, although there is less overlap with the other two studies. Nonetheless, EPA's Reference Dose and the analysis supporting its derivation was reviewed positively by the National Academcy of Sciences and the Agency continues to support its level and the implications. We conclude that any analysis of the IQ benefits needs to deploy several models  with a threshold and without to capture the full range of uncertainty. EPA acknowledges that there are complexities, including a variety of potential confounders, that must be considered in relation to potential cardiovascular mortality linked to methylmercury exposure. For additional discussion of this endpoint, see Appendix D.

D. Other Comments Comment:

One commenter ( OAR 2002 0056 5476) reports that to date, it has yet to receive any responses to its request to EPA Region 5 to fulfill their Trust responsibilities and intervene on the commenter's behalf in the rule making process. Therefore, this commenter is calling on EPA Headquarters to act on its behalf and set MACT standards that will reduce Hg emissions from 9 298 utilities by 90 percent in the next 10 years. This will also fulfill EPA's obligations under the Environmental Justice Doctrine. As outlined in the Forest County Potawatomi's comment letter to EPA ( see e docket OAR 2002 0056 2173: April 27, 2004), EPA has recognized its special obligation to protect the environmental interests of the commenter when carrying out its duties. The Indian Policy, first adopted in 1984, also calls for EPA to work directly with tribes on a government to government basis and to encourage tribes to participate in policy making. It has not been made known to the commenter of any efforts that EPA has made to fulfill any of these obligations. No consultation has taken place with the commenter, and the commenter's requests for Trust responsibility to be carried out have remained unaddressed.

Response:

EPA recognizes that the Federal government stands in a government to government relationship with Federally recognized Tribes and has certain trust responsibilities to these Tribes. This relationship and responsibility should guide EPA in the implementation of policies and actions that affect Tribes. Pursuant to the government to government relationship, EPA consults with Tribes regarding actions that affect Tribes. In addition, treaties, statutes, and executive orders create Federal obligations regarding Tribal resources. EPA believes that its actions in developing the final rule have been consistent with the government to government relationship and that the final rule itself is consistent with the trust responsibility.

EPA does not agree with the commenters who claim that it did not consult with tribes in developing the rule. As explained in the discussion of EPA compliance with EO in the preamble for the final rule, EPA took the following steps to consult with Tribes. EPA gave a presentation to a national meeting of the National Tribal Environmental Council ( NTEC) in April 2001, and encouraged Tribal input at an early stage. EPA then worked with NTEC to find a Tribal representative to participate in the workgroup developing the rule, and included a representative from the Navajo Nation as a member the official workgroup, with a representative from the Campo Band later added as an alternate. In March 2004, EPA provided a briefing for Tribal representatives, the newly formed National Tribal Air Association ( NTAA), and NTEC. EPA received comments on this rule from a number of Tribes, and has taken those comments and other input from Tribal representatives into consideration in development of this rule.

EPA disagrees that the rule will not adequately protect Tribal fishing rights. EPA agrees that some Tribes have unique legal rights to fish arising from treaties, statutes, executive orders, and agreements. EPA also recognizes that Tribal members may catch and consume more fish than the general public as a result of Tribal fishing rights as well as Tribal culture, traditions, and subsistence lifestyles.

EPA believes that this regulation adequately protects Tribal health and is consistent with the trust responsibility for several reasons. First, the commenters understate the significance of the fact that Hg emissions from Utility Units currently are not subject to performance standards. This regulation will for the first time establish performance standards applicable to Hg emissions, and those standards will require significant reductions in the levels of Hg emissions. 9 299 Such reductions will provide greater protection to Tribal fish resources than would otherwise be available. Acting to provide such heightened protection is consistent with both the statute and the Federal trust responsibility.

Moreover, the commenters offer no specific evidence that the Hg emissions reductions from this regulation will not adequately protect Tribal health. Their main contention is that the regulatory approach set forth in an earlier EPA proposal would have produced a 90 percent reduction in Hg emissions and that any smaller reduction is, therefore, inadequate. That contention rests on a misconception of an earlier Federal Register Notice, which proposed a finding, but did not contain any specific proposal for Hg emissions regulations, and, therefore, did not provide for any percentage of reduction. EPA has never proposed any such rule. EPA believes that this regulation will adequately protect Tribal health.

The commenters also argue that EPA has not adequately considered the significance of Tribal fish consumption patterns, specifically the fact that Tribal fishers consume more fish than the general population. That comment is misplaced. As described in more detail elsewhere in this document, EPA carefully analyzed available information on fish consumption by Tribal members and other sub populations, and determined how to use the available data most appropriately. One basis for EPA's analysis was a study of tribal fish consumption in one region to model consumption by other Tribes as well as other subpopulations. EPA's approach was to identify areas where the effects of Hg deposition from utility emissions had the greatest effects. EPA then compared those high deposition areas with locations with high Tribal populations to assess the areas of greatest potential risk to Tribes. That analysis found that very few areas where Native Americans live corresponds with high residual Hg deposition caused by utilities. It found further, that the standards established in the regulation will significantly reduce risks to tribal members.

Finally, as discussed in the preamble to the regulation, this regulation establishes a capand trade program for Indian country.

As part of its analysis of the this final rule, EPA has estimated the some of the health benefits of reducing Hg from utilities. At this time EPA is only able to provide quantative estimates of the benefits of reducing neurological impacts of exposure to MeHg for a portion of the U. S. population. This population covers people who recreationally catch and consume freshwater fish. The RIA for this rule contains this analysis in Chapter 11. As part of its assessment, EPA provides estimates for the benefits of this rulemaking to subsistence fishers, including case study examples of the benefits to the some members of the Chippewa Tribe, the Hmong, and low income fishers.

Comment:

One commenter ( OAR 2002 0056 5476) notes that EPA has a specific obligation to protect tribal way of life and cultural resources, not only rights and resources. Court decisions have held that trust responsibility is not limited to the protection of treaty rights, reservation 9 300 lands, and other property held in trust for the tribes and that federal agencies may not permit actions which would interfere with treaty rights. Instead, trust responsibility extends to all actions of the federal governments that may affect Indian tribes, including those rights, resources, and interests recognized under treaty, statue, executive order, and common law.

The commenter's rights include rights to the lands, waters, and natural environment of the Reservation. Arizona v. California, 373 U. S. 546 ( 1963) holds that tribes are entitled to sufficient water and other resources to make the Reservation livable and to maintain their way of life. Tribes also hold rights to hunt, fish and gather on reservation lands and waters.

In addition, Congress has specifically recognized the applicability of the trust responsibility in tribal cultural resources by instating a number of federal laws in this area. Further, the Tribes' right to practice traditional religions under the First Amendment is recognized in the American Indian Religious Freedom Act, 42 U. S. C. Section 1996, 1996a. The EPA has fallen far short of its obligations in this rulemaking.

Though the Environmental Justice guidelines dictate that EPA must identify and address disproportionately high and adverse human health or environmental effects of its programs, policies, and activities on minority populations and low income populations, unfortunately, it appears as though these guidelines are being largely ignored for the purposes of providing special treatment to utilities. The commenter encourages EPA to assure the Tribes that EPA is actively addressing these Environmental Justice issues per the guidelines EPA has set out for itself.

Response:

EPA recognizes that the Federal government stands in a government to government relationship with Federally recognized Tribes and has certain trust responsibilities to these Tribes. This relationship and responsibility should guide EPA in the implementation of policies and actions that affect Tribes. Pursuant to the government to government relationship, EPA consults with Tribes regarding actions that affect Tribes. In addition, treaties, statutes, and executive orders create Federal obligations regarding Tribal resources. EPA believes that its actions in developing the final rule have been consistent with the government to government relationship and that the final rule itself is consistent with the trust responsibility.

EPA does not agree with the commenters who claim that it did not consult with tribes in developing the rule. As explained in the discussion of EPA compliance with EO in the preamble for the final rule, EPA took the following steps to consult with Tribes. EPA gave a presentation to a national meeting of the National Tribal Environmental Council ( NTEC) in April 2001, and encouraged Tribal input at an early stage. EPA then worked with NTEC to find a Tribal representative to participate in the workgroup developing the rule, and included a representative from the Navajo Nation as a member the official workgroup, with a representative from the Campo Band later added as an alternate. In March 2004, EPA provided a briefing for Tribal representatives, the newly formed National Tribal Air Association ( NTAA), and NTEC. EPA received comments on this rule from a number of Tribes, and has taken those comments and 9 301 other input from Tribal representatives into consideration in development of this rule.

EPA disagrees that the rule will not adequately protect Tribal fishing rights. EPA agrees that some Tribes have unique legal rights to fish arising from treaties, statutes, executive orders, and agreements. EPA also recognizes that Tribal members may catch and consume more fish than the general public as a result of Tribal fishing rights as well as Tribal culture, traditions, and subsistence lifestyles.

EPA believes that this regulation adequately protects Tribal health and is consistent with the trust responsibility for several reasons. First, the commenters understate the significance of the fact that Hg emissions from Utility Units currently are not subject to performance standards. This regulation will for the first time establish performance standards applicable to Hg emissions, and those standards will require significant reductions in the levels of Hg emissions. Such reductions will provide greater protection to Tribal fish resources than would otherwise be available. Acting to provide such heightened protection is consistent with both the statute and the Federal trust responsibility.

Moreover, the commenters offer no specific evidence that the Hg emissions reductions from this regulation will not adequately protect Tribal health. Their main contention is that the regulatory approach set forth in an earlier EPA proposal would have produced a 90 percent reduction in Hg emissions and that any smaller reduction is, therefore, inadequate. That contention rests on a misconception of an earlier Federal Register Notice, which proposed a finding, but did not contain any specific proposal for Hg emissions regulations, and, therefore, did not provide for any percentage of reduction. EPA has never proposed any such rule. EPA believes that this regulation will adequately protect Tribal health.

The commenters also argue that EPA has not adequately considered the significance of Tribal fish consumption patterns, specifically the fact that Tribal fishers consume more fish than the general population. That comment is misplaced. As described in more detail elsewhere in this document, EPA carefully analyzed available information on fish consumption by Tribal members and other sub populations, and determined how to use the available data most appropriately. One basis for EPA's analysis was a study of tribal fish consumption in one region to model consumption by other Tribes as well as other subpopulations. EPA's approach was to identify areas where the effects of Hg deposition from utility emissions had the greatest effects. EPA then compared those high deposition areas with locations with high Tribal populations to assess the areas of greatest potential risk to Tribes. That analysis found that very few areas where Native Americans live corresponds with high residual Hg deposition caused by utilities. It found further, that the standards established in the regulation will significantly reduce risks to tribal members.

Finally, as discussed in the preamble to the regulation, this regulation establishes a capand trade program for Indian country.

As part of its analysis of the this final rule, EPA has estimated the some of the health 9 302 benefits of reducing Hg from utilities. At this time EPA is only able to provide quantative estimates of the benefits of reducing neurological impacts of exposure to MeHg for a portion of the U. S. population. This population covers people who recreationally catch and consume freshwater fish. The RIA for this rule contains this analysis in Chapter 11. As part of its assessment, EPA provides estimates for the benefits of this rulemaking to subsistence fishers, including case study examples of the benefits to the some members of the Chippewa Tribe, the Hmong, and low income fishers.

Comment One commenter ( OAR 2002 0056 5492) made the following recommendations to the EPA regarding development of a final proposal for Hg control:

° Carbon Injection ( ACI) is maturing quickly. Using a methodology that says subbituminous coal needs a credit multiplier or higher emissions, results in fuel bias against bituminous coal and the states that produce bituminous coal.

° The commenter believes that wet ESPs and SCRs remove more oxidized Hg than EPA results show.

° The western coal state congressional delegations, who are saying that technology will not be available to remove Hg from their sub bituminous coal, are ignoring the benefits America has already received from investments in developing clean coal technology for Hg removal and punishing bituminous coal users.

° A MACT standard should be fuel neutral, i. e., no separate standards for different coal ranks.

° A fuel neutral MACT of 3.0 lbs Hg/ TBtu or less for existing EGUs will reduce Hg emissions to less than 34 tons/ year.

° A MACT standard should incorporate an alternative method to calculate plant Hg emissions limits based on a percent reduction from the raw coal as mined. Such an alternative would provide some amount of relief for those coals with unusually high Hg content while still achieving meaningful reductions.

° Under the alternative cap and trade proposals, implementation dates should be adjusted to coincide with other regulatory actions, including the Clean Air Interstate Rule and multi pollutant strategies such as Clear Skies.

° A cap and trade rule should not include Fuel Adjustment Factors.

° A cap and trade rule should address so called " hot spots" that could result from allowance trading. 9 303 The commenter appreciated the opportunity to provide comments to the U. S. EPA regarding the proposed Hg regulations. The commenter would be pleased to provide additional information and are willing to meet with the U. S. EPA regarding our statement.

Response:

EPA has examined the commenter's concerns in context of the final rulemaking. EPA is finalizing a cap and trade approach under section 111. Please see the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112.

EPA appreciates the commenter's input to the record on the status of control technologies. The Agency's position on the state of Hg technology is contained in the EPA ' s Office of Research and Development white paper ( see Control of Emissions from Coal Fired Electric Utility Boilers: An Update, EPA/ Office of Research and Development, March 2005).

Comment:

One commenter ( OAR 2002 0056 5571) reports key public power concerns in response to the EPA NODA. This commenter prefers a cap and trade approach to controlling Hg without disadvantaging smaller utilities with only one generating unit or few fuel options. The commenter endorses comments from UARG and PERI.

The commenter continues to support an exemption for small units and requests that EPA streamline the monitoring requirements for small and/ or exempt units regardless of decision to use cap and trade approach ( Sec. 111 or 112 ( n) ( 1) ( A) or MACT Approach:

The commenter believes that EPA should provide for alternative treatment for small utilities ~ 50 MW. ( Questions 5 & 6)

With regard to de minimis threshold, this commenter continues to support EPA's suggested exemption for units that emit less than 25 pounds of Hg annually, and encourages EPA to extend the exemption to units that emit up to 50 pounds a year. EPA's re examination of the benefits associated with the Utility MACT in the NODA lends further support to an exemption. As EPA notes in the NODA, there are open issues regarding the benefits of the total Hg reductions being proposed in the Utility MACT for all electric utility steam generating units in the U. S. This issue is even more relevant to the minimal emissions from small units, where the costs of monitoring and compliance are clearly significant, but the benefits are small and uncertain. For this reason, and the others set out in the commenter's previous comments in this rulemaking, including the likelihood that many of the commenter's smaller units will be forced to close under the pressure of the Utility MACT rule and the Clean Air Interstate Rule ( CAIR rule), and the impacts of that on the national transmission grid), the commenter requests that EPA exempt these 9 304 small units from the Utility MACT.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

With regard to monitoring for smaller utilities, one commenter ( OAR 2002 0056 5571) requests that EPA also simplify monitoring for smaller and/ or exempt units. Monitoring costs present a significant compliance cost, particularly for small units, and one that is unwarranted in light of the minimal risk that these units pose. For an exempt unit, the monitoring costs to prove that a unit is exempt could prove to be as significant as the costs of compliance with the rule, thereby defeating the purpose of the exemption. EPA estimates the capital cost of Hg CEMS range from $ 95,000 to $ 135,000. Annual operating and maintenance costs are estimated to range between $ 45,000 to $ 65,000. Under the upper end of the range, the first year's monitoring cost, equal to $ 200,000 per year, would be in the same range as controlling for Hg through allowance purchases ($ 20,000) for a unit that emitted, as many of the commenter's members do, about 10 pounds per year.

The commenter notes that not only are the monitoring costs for these small units enormous, but they are particularly inappropriate in light of the minimal risks presented by small units. Units subject to a 50 pound exemption account for a small fraction of the Hg emitted in the U. S. The total Hg emissions from these units are just over 6 tons per year, or less than 15 percent of the Hg emitted from all coal fired power plants. The emissions for all units less than 25 pounds are less than 2 tons per year, or less than 5 percent of total Hg emissions. Further, as EPA notes in the NODA, there are open issues regarding the benefits of the total Hg reductions from all utilities in the U. S. discussed in the Utility MACT. This raises serious questions about the even smaller and less certain benefits of regulating small emitters, particularly when monitoring and compliance costs for the small emitters are substantial.

The commenter recommends that for these small and/ or exempt units, EPA adopt the Hg monitoring requirements that have already been developed for small units in the context of another MACT rulemaking. The MACT for Industrial, Commercial and Institutional Boilers and Process Heaters applies to utility boilers that generate equal to or less than 25 MW ( as well as industrial units that generate less than 25 MW) and includes requirements for Hg testing. See National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters, 69 Fed. Reg. 55,218 ( September 13, 2004). These testing requirements are particularly appropriate for the smaller units in the Utility MACT, which have significant similarities to the units in the Boiler MACT, including small size and limited emissions. 9 305 The monitoring requirements for the Boiler MACT include initial and annual stack tests ( using EPA method 29, Part 60, Appendix A or ASTM D6784 02), or, in the alternative, fuel testing ( using ASTM D3684 01, see Table 6 attached). The general monitoring requirements from the Industrial Boiler MACT are attached in Appendix II to these comments. These monitoring requirements, including the continuous compliance requirements, are more appropriate to small and/ or exempt units in the Utility MACT rule than the significant costs associated with CEMS, while ensuring that these units continue to qualify as small and/ or exempt.

If EPA determines that Boiler MACT monitoring requirements cannot be used of Utility MACT, the commenter also encourages the EPA to adopt phased in monitoring requirements for small and/ or exempt units. There are still significant uncertainties associated with the current monitoring technology. These technology issues will present a particular hardship on municipally owned utilities. Smaller municipal utilities face substantial challenges because they lack the resources to address these monitoring issues and are unable to get priority in hiring consultants. EPA should delay the Hg monitoring requirements for exempt and/ or small sources until at least 2010 when Hg monitoring technology may be more fully developed, demonstrated, and less expensive.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

One commenter ( OAR 2002 0056 5571) believed that should a cap and trade program be implemented, EPA has proposed an exemption for small emitters. It suggests an exemption for units that emit 25 pounds or less. According to EPA's data, this would apply to 3.9 percent of emissions nationwide. The commenter believed that EPA should restyle the small emitter exemption so that it applies to existing units at small plants emitting, with a minimum of 25 pounds on a per unit basis.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

One commenter ( OAR 2002 0056 5571) urges the EPA to also consider other de minimis options offered by public power communities ( including the > 95 pound plant wide suggestion for community utilities that meet the SBREFA definition). Earlier the commenter provided 9 306 references to the UMRA, Regulatory Flexibility Act, SBREFA Act of 1996 and Executive Order 12866 that would justify making some practical decisions about a de minimis exemption. Whatever de minimis level the EPA ultimately sets in the final rule. The commenter does not believe that this de minimis should not subject the larger units/ plants to more stringent cap levels.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

One commenter ( OAR 2002 0056 5571) believes that the EPA's final rule should emphatically state that the smaller utility systems ( particularly those that meet the SBREFA definition) should be able to work with their state agencies and permit writers to determine the most practical and reliable method to perform monitoring functions at lowest cost ( considering capital expense, operating and maintenance, and on going staff training expenses). Many public power utilities simply don't have the personnel skills to perform these highly sophisticated monitoring runs. Also many public power communities are two hours away from major metropolitan areas or airport hubs so that frequent visits by CEM manufacturers, vendors, contractors, or service personnel would be prohibitively expensive.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

One commenter ( OAR 2002 0056 5571) strongly urges the U. S. EPA to encourage states to work with the smaller Hg emitters to allow creative Hg reduction/ mitigation/ removal or prevention projects. Holland Board of Public Works is a municipal utility with approximately 30,000 households in Michigan. Earlier in 2004 the municipal utility initiated a community program to encourage the voluntary return of Hg thermometers to reduce Hg from household environments, landfills and the wastewater system. The utility provided digital thermometers to those who returned a glass thermometer containing Hg or other Hg containing items. In the span of a few months the Holland Board of Public Works collected 28 pounds of Hg through this program in addition to working with commercial industrial customers. Comparatively, the Holland Board of Public Works emits approximately 8 pounds of total Hg annually through combined oil, coal and gas generation. The commenter believes that the EPA and states should encourage alternative methods like this innovative method to reduce Hg that are cost effective in the final rule. The Clean Air Act authorized the EPA to consider work practices and other 9 307 alternatives when they are demonstrated to be effective and can be proven. The commenter strongly urges the EPA to allow state agencies to work with smaller emitters on this type of alternative to MACT if the EPA promulgates a MACT standard or if it authorizes a cap and trade program that a state declines to opt into.

Response:

As discussed above and in the final rule preamble ( section IV. D. 3. iv), EPA is not finalizing a low emitter exclusion and EPA recommends States address small business entities through the allocation process.

Comment:

The commenter ( OAR 2002 0056 5455) also took issue with the modeling performed in the analysis. The commenter does not believe the science of modeling has reached a point where it can accurately be used for Hg transport and deposition due to the lack of understanding about dry deposition. Few deposition monitors exist in Indian Country so it's very hard to say how much wet or dry deposition is occurring in these areas 15. Based on this concern, the commenter believed it is reckless to propose a cap and trade program relying on the results of EPA's models. It is better to err on the side of caution than to be wrong in such an important matter. To account for the lack of confidence in the models, EPA should abandon its idea of cap and trade and stick to a MACT standard.

The commenter believed that the air emission inventories used in EPA's analysis probably underestimated the amount of Hg emitted from some sources, such as miscellaneous product disposal. EPA has used the best information it has available, but it should leave a margin of safety to account for inaccuracies.

Response:

EPA is finalizing a cap and trade approach under section 111. Please see the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112.

Comment:

The commenter ( OAR 2002 0056 5551) stated that firstly, standards for controlling HAPs from coal fired power plants must follow the requirements of Section 112 of the Clean Air Act. The commenter noted that for existing power plants, each MACT limit must be at least as stringent as the limit which is achievable by the average of the best controlled 12 percent of similar units for which there is data. The commenter noted that this is commonly referred to as the MACT floor. The commenter stated that the standards should be more stringent if justified by 9 308 cost, benefit and feasibility. According to the commenter, hence, the NODA information on costs and benefits is primarily relevant for setting more stringent standards than the MACT floor. The commenter believed that the NODA is useful for setting MACT standards better than the MACT floor for subbituminous and lignite coal combustion, if a coal neutral standard is not set. The commenter stated that, however, information on costs and benefits are irrelevant to the setting of the MACT floor.

While the commenter believed that the choice of 3 mg per MWh or 90 percent control, annual averages, is an appropriate MACT standard for all coals, the commenter noted that EPA may choose to set MACT limits by principle coal type, i. e., bituminous, subbituminous, and lignite. In such an event, the commenter recommended that EPA set better than the MACT floor limits for subbituminous and lignite coals in view of the generally limited control systems currently in place for these coals and the recent success in controlling Hg from these coals using halogenated activated carbon injection. The commenter stated that the rate component of the standard should remain the same as bituminous coal to facilitate compliance determination for blended coals. The commenter added that, alternatively, blended coals should be subject to the most stringent rate for the coals being blended. The commenter stated that the control efficiency component of a MACT limit for subbituminous and lignite coals could be somewhat less stringent than for bituminous coals, in view of the somewhat lower Hg content of these coals and the lesser amount of data for control of Hg from these coals. According to the commenter, 3 mg per MWhr or 80 percent control would be a reasonable MACT standard for these coals at this time.

Response:

EPA is finalizing a cap and trade approach under section 111. Please see the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112.