release actuation event, except for potential leaks through the bonnet
vent due to bellows failure or fatigue which are not considered PRD
actuation. Pilot-operated PRDs use a small pilot safety valve that
discharges to the atmosphere to actuate the primary valve or piston,
which then discharges to a control system. The EPA considers balanced
bellows and pilot operated PRDs to be equipment that safely controls
the primary PRD release and reduces HAP emissions to the atmosphere.
    The PRDs subject to the Site Remediation NESHAP that vent to a
control device are exempt from LDAR. The PRDs that vent to the
atmosphere are subject to the LDAR provisions of either 40 CFR part 63,
subpart TT or UU. Similar to the current provisions, the proposed LDAR
provisions for PRDs require all PRDs that vent to the atmosphere be
tested using EPA Method 21 to ensure the PRD is not leaking above the
detection threshold during normal operation and to ensure it properly
reseats if a release does occur. Those PRDs that vent to control
systems would still be exempt from LDAR requirements given that if a
release were to occur from this specific class of PRDs, it would vent
to a closed vent system and control device.
    Finally, to ensure compliance with the proposed work practice
standard for emissions released from PRD actuation events that vent
directly to the atmosphere, we are also proposing to require that
sources monitor these PRDs using a system that is capable of
identifying and recording the time and duration of each pressure
release and of notifying operators that a pressure release is
occurring. Pressure release actuation events from PRDs that vent
directly to the atmosphere have the potential to emit large quantities
of HAP. When a pressure release occurs, it is important to identify and
mitigate it as quickly as possible. We are proposing to allow owners
and operators to use a range of methods to satisfy the PRD actuation
detection requirements, including the use of a parameter monitoring
system (that may already be in place) on the process that is sufficient
to indicate that a pressure release has occurred as well as record the
time and duration of that pressure release. For the purposes of
estimating the costs of this requirement, we assume that all PRDs that
would become subject to the proposed standards already have a process
or parameter monitoring system that will indicate the time that a
pressure release has occurred and the duration of the release.
    As part of these proposed provisions, we are proposing to add
definitions for ``pressure release actuation event'' and ``pressure
relief device or valve,'' to 40 CFR part 63, subpart GGGGG. We are also
proposing to remove the definition of ``safety device'' and the
provisions related to safety devices from 40 CFR part 63, subpart
GGGGG, which would overlap and be redundant with parts of the proposed
definition of ``pressure relief device or valve'' and the provisions
related to these devices. To our knowledge, pressure relief devices or
valves are the only relevant safety devices used in site remediation
processes.
    The Agency recognizes that the treatment of PRDs should be
appropriate to the characteristics of the relevant source category and
need not be

uniform across all source categories. In developing this proposal, the
EPA was mindful of the limited information it has with respect to PRDs
in site remediation and the diversity of site characteristics. The EPA
seeks comment on whether there are PRDs associated with affected
facility process vents, tanks, containers, separators, or closed vent
systems, and whether PRDs associated with those affected facilities are
routed to a control device through a closed vent system or vent to the
atmosphere. The EPA seeks comment on whether facilities that are
subject to the Site Remediation NESHAP are also subject to EPA's CAP at
40 CFR part 68, OSHA's Process Safety Management rule at 29 CFR
1910.119, BAAQMD Rule 8-28-304, or SCAQMD Rule 1173, and if the latter
set of rules extend to cover PRDs associated with site remediation. The
EPA has proposed MACT work practice standards for PRDs that vent to the
atmosphere based on the best performing sources that are subject to the
other similar NESHAP (40 CFR part 63, subpart CC-Petroleum Refineries,
and 40 CFR part 63, subpart DD--Offsite Waste and Recovery Operations).
The EPA seeks comment on whether these MACT work practice standards for
PRDs are appropriate for site remediation.
    For the purposes of estimating the costs of this requirement, we
have assumed that operators have existing systems that are capable of
identifying a pressure release to the atmosphere and recording the time
and duration of the event. The EPA has further assumed there is one PRD
per site remediation facility, and one pressure event every 3 years
that would cause the PRD to actuate, triggering an analysis of the
cause of the pressure release actuation event and the need for
corrective measures. The EPA seeks comment on these assumptions.
(Comment C-2) Whether or not data and comments substantiate that there
are currently PRDs at site remediation facilities, the EPA may adopt
provisions addressing PRDs if we conclude that future site-remediation
affected facilities may use these devices.
    For further details on the assumptions and methodologies used in
this analysis, see the technical memorandum titled Review of Regulatory
Alternatives for Certain Vent Streams in the Site Remediation Source
Category, which is in Docket ID No. EPA-HQ-OAR-2018-0833.

B. What are the results of the risk assessment and analyses for
affected sources?

    As described above, for the Site Remediation source category, we
conducted an inhalation risk assessment for all HAP emitted, a
multipathway screening assessment for the PB-HAP emitted, and an
environmental risk screening assessment for the PB-HAP and acid gases
(e.g., HCl) emitted from affected sources. We present results of the
risk assessment briefly below and in more detail in the Residual Risk
Assessment for the Site Remediation Source Category in Support of the
2019 Risk and Technology Review Proposed Rule, which is available in
the docket for this action.
1. Chronic Inhalation Risk Assessment Results
    The results of the chronic baseline inhalation cancer risk
assessment indicate that, based on estimates of current actual and
allowable emissions, the MIR posed by the Site Remediation source
category is 1-in-1 million driven by site remediation model plant
emissions of arsenic compounds and chromium (VI) compounds. The total
estimated cancer incidence based on actual and allowable emission
levels is 0.001 excess cancer cases per year, or 1 case every 1,000
years. The population exposed to cancer risks greater than or equal to
1-in-1 million considering actual and allowable emissions is 400 (see
Table 2 of this preamble). In addition, the maximum chronic noncancer
HI (TOSHI) is less than 1.

                                    Table 2--Site Remediation Inhalation Risk Assessment Results for Affected Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Estimated
                                                   Maximum         population at     Estimated annual
          Number of facilities \1\                individual       increased risk    cancer incidence   Maximum chronic      Maximum  screening acute
                                               cancer risk  (in  of cancer  >=1-in-  (cases per year)   noncancer TOSHI            noncancer HQ
                                                  1 million)         1 million
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Based on Actual Emissions Level \2\ \3\
                                             -----------------------------------------------------------------------------------------------------------
102.........................................                  1                400              0.001                0.1  HQREL = 1
                                                                                (arsenic compounds).
                                             -----------------------------------------------------------------------------------------------------------
                                                                                Based on Whole Facility Emissions
                                             -----------------------------------------------------------------------------------------------------------
                                                          1,000          2,300,000                0.5                  5  ..............................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.

2. Screening Level Acute Risk Assessment Results
    As presented in Table 2 of this preamble, acute exposure to
emissions from affected sources in the Site Remediation source category
result in a maximum HQ of 1 based on the REL for arsenic compounds. For
more detailed acute risk results refer to the Residual Risk Assessment
for the Site Remediation Source Category in Support of the 2019 Risk
and Technology Review Proposed Rule, which is available in the docket
for this action.
3. Multipathway Risk Screening Results
    The results of the multipathway risk screening assessment indicate
all Tier 2 screening values for PB-HAP emitted from the source category
(arsenic compounds, cadmium compounds, mercury compounds, and POM) are
less than 1. Based on these results, we are confident that the cancer
risks due to multipathway exposures to these chemicals are lower than
1-in-1 million and the noncancer HIs are less than 1.
    In the case of lead, the multipathway risks were assessed by
comparing modeled ambient lead concentrations against the primary NAAQS
for lead. The results of this analysis indicate that, based on actual
and allowable emissions, the maximum annual off-site ambient lead
concentration is 0.0001 [micro]g/m\3\, well below the primary NAAQS of
0.15 [micro]g/m\3\.

4. Environmental Risk Screening Results
    The ecological risk screening assessment indicated all modeled
points were below the Tier 1 screening thresholds based on actual and
allowable emissions of PB-HAP (arsenic compounds, cadmium compounds,
mercury compounds, and POM) and acid gases (HCl and HF) emitted by the
source category.
    In the case of lead, the environmental risks were assessed by
comparing modeled ambient lead concentrations against the secondary
NAAQS for lead. The results of this analysis indicate that, based on
actual and allowable emissions, the maximum annual off-site ambient
lead concentrations were below the secondary NAAQS.
    Based on the results of the environmental risk screening
assessment, we would not expect environmental risks due to emissions
from this source category.
5. Facility-Wide Risk Results
    An assessment of whole-facility (or ``facility-wide) risks was
performed as described above to characterize the source category risk
in the context of facility-wide risks.\21\ Facility-wide risks were
estimated using the NEI-based data. The maximum lifetime individual
cancer risk posed by the 102 facilities, based on facility-wide
emissions, is 1,000-in-1 million, with ethylene oxide emissions from
facility-wide flares, transfer racks, vents, and fugitive emissions
driving the risk. The total estimated cancer incidence based on whole
facility emissions is 0.5 excess cancer cases per year, or one excess
case in every 2 years. Approximately 2,300,000 people are estimated to
have cancer risks above 1-in-1 million from facility-wide HAP
emissions. Facility-wide lifetime individual cancer risks are estimated
to be greater than or equal to 100-in-1 million at three facilities and
55,000 people would be exposed at or above this risk level. Additional
details on this determination can be found in the Residual Risk
Assessment for the Site Remediation Source Category in Support of the
2019 Risk and Technology Proposed Rule, which is available in the
docket for this action.
---------------------------------------------------------------------------

    \21\ The facility-wide risk assessment includes all emission
points within the Site Remediation source category (including those
for which there are no standards) as well as other emission points
covered by other NESHAP.
---------------------------------------------------------------------------

    Regarding the facility-wide risks due to ethylene oxide (described
above), which are due to emission sources that are not part of the Site
Remediation source category, we intend to evaluate those facility-wide
estimated emissions and risks further and may address these in a
separate future action, as appropriate. In particular, the EPA is
addressing ethylene oxide based on the results of the latest NATA
released in August 2018, which identified the chemical as a potential
concern in several areas across the country. (NATA is the Agency's
nationwide air toxics screening tool, designed to help the EPA and
state, local, and tribal air agencies identify areas, pollutants, or
types of sources for further examination.) The latest NATA estimates
that ethylene oxide significantly contributes to potential elevated
cancer risks in some census tracts across the U.S. (less than 1 percent
of the total number of tracts). These elevated risks are largely driven
by an EPA risk value that was updated in late 2016. The EPA will work
with industry and state, local, and tribal air agencies as the EPA
takes a two-pronged approach to address ethylene oxide emissions: (1)
Reviewing and, as appropriate, revising CAA regulations for facilities
that emit ethylene oxide--starting with air toxics emissions standards
for miscellaneous organic chemical manufacturing facilities and
commercial sterilizers; and (2) conducting site-specific risk
assessments and, as necessary, implementing emission control strategies
for targeted high-risk facilities. The EPA will post updates on its
work to address ethylene oxide on its website at: https://www.epa.gov/ethylene-oxide. Regarding the noncancer risk assessment, the maximum
chronic noncancer HI associated with facility-wide emissions is
estimated to be 5 due to natural gas external combustion boiler
emissions of chlorine. A total of three facilities had a facility-wide
chronic noncancer HI greater than 1; two due to emissions of chlorine
and one due to emissions of trichloroethylene.
6. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice issues that
might be associated with the source category, we performed a
demographic analysis, which is an assessment of risk to individual
demographic groups of the populations living within 5 km and within 50
km of the facilities. In the analysis, we evaluated the distribution of
HAP-related cancer and noncancer risk from the Site Remediation source
category across different demographic groups within the populations
living near facilities.\22\
---------------------------------------------------------------------------

    \22\ Demographic groups included in the analysis are: White,
African American, Native American, Hispanic or Latino, other races
and multiracial, people living below the poverty level, people
living above the poverty level, adults without a high school
diploma, adults with a high school diploma, and linguistically
isolated people.
---------------------------------------------------------------------------

    The results of the demographic analysis are summarized in Table 3
below. These results, for various demographic groups, are based on the
estimated risk from actual emissions levels for the population living
within 50 km of the facilities.

               Table 3--Site Remediation: Demographic Assessment Results--50 km Study Area Radius
----------------------------------------------------------------------------------------------------------------
                                                                             Population with
                                                                              cancer risk at    Population with
                                                             Nationwide      or above 1-in-1    chronic hi above
                                                                              million due to     1 due to site
                                                                             site remediation     remediation
----------------------------------------------------------------------------------------------------------------
Total Population.......................................        317,746,049                374                  0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White..................................................                 62                 83                  0
Minority...............................................                 38                 17                  0
----------------------------------------------------------------------------------------------------------------
                                               Minority by Percent
----------------------------------------------------------------------------------------------------------------
African American.......................................                 12                 14                  0
Native American........................................                0.8                0.4                  0

Hispanic or Latino (includes white and nonwhite).......                 18                  0                  0
Other and Multiracial..................................                  7                  2                  0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level....................................                 14                 13                  0
Above Poverty Level....................................                 86                 87                  0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without High School Diploma................                 14                 11                  0
Over 25 and with a High School Diploma.................                 86                 89                  0
----------------------------------------------------------------------------------------------------------------
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated................................                  6                  0                  0
----------------------------------------------------------------------------------------------------------------

    The results of the Site Remediation source category demographic
analysis indicate that emissions from the source category expose
approximately 400 people to a cancer risk at or above 1-in-1 million
and no people to a chronic noncancer TOSHI greater than 1. The
percentages of the at-risk population in each demographic group (except
for White) are similar to or lower than their respective nationwide
percentages with the exception of the African American, Above Poverty
Level, and Over 25 and with a High School Diploma demographic groups,
which are slightly higher than their respective nationwide percentages.
    The methodology and the results of the demographic analysis are
presented in a technical report, Risk and Technology Review--Analysis
of Demographic Factors for Populations Living Near Site Remediation
Source Category Operations, available in the docket for this action.

C. What are our proposed decisions regarding risk acceptability, ample
margin of safety, and adverse environmental effect?

1. Risk Acceptability
    We weigh all health risk factors in our risk acceptability
determination, including the cancer MIR, the number of persons in
various cancer and noncancer risk ranges, cancer incidence, the maximum
noncancer TOSHI, the maximum acute noncancer HQ, the extent of
noncancer risk, the distribution of cancer and noncancer risks in the
exposed population, and risk estimation uncertainties (54 FR 38044,
September 14, 1989).
    For the Site Remediation source category, the risk analysis
indicates that for affected sources, the cancer risk to the individual
most exposed is 1-in-1 million from both actual and allowable
emissions. These risks are considerably less than 100-in-1 million,
which is the presumptive upper limit of acceptable risk. The risk
analysis for affected sources also estimated a cancer incidence of
0.001 excess cancer cases per year, or 1 case every 1,000 years.
Exposures to HAP with noncancer health effects are estimated to result
in a maximum chronic noncancer TOSHI below 1 (0.1), as well as a
maximum acute HQ value of 1. Multipathway screening values for affected
sources are below a level of concern for both carcinogenic and non-
carcinogenic PB-HAP as well as emissions of lead compounds. Considering
all the health risk information and factors discussed above, including
the uncertainties, we propose to find that risk from the affected
facilities in the Site Remediation source category subject to the Site
Remediation NESHAP is acceptable.
2. Ample Margin of Safety Analysis
    Under the ample margin of safety analysis, we evaluated the cost
and feasibility of available control technologies and other measures
(including the controls, measures, and costs reviewed under the
technology review) that could be applied in this source category to
further reduce the risks (or potential risks) due to emissions of HAP.
    As discussed above, we are proposing that the risks from this
source category are acceptable. For affected sources, the maximum
cancer risk to the individual most exposed is 1-in-1 million from both
actual and allowable emissions from site remediation processes and
activities. Of the affected sources, two facilities had cancer risks
equal to 1-in-1 million. Neither of these facilities had site
remediation emissions reported to the NEI, and instead risks for both
were based on estimated emissions.
    In our ample margin of safety analysis, we identified three control
options that could further reduce HAP emissions from the source
category. We evaluated those options to determine whether any of the
three options is required to provide an ample margin of safety to
protect public health. For process vents at affected sources, as
discussed in section IV.D of this preamble, we identified an emissions
control option requiring compliance with a 98-percent reduction rather
than a 95-percent reduction in HAP emissions. To assess the maximum
potential for risk reduction that could result from this process vent
control option, we assumed that the maximum risks for the site
remediation source category are due to emissions from a process vent
with emissions controlled at 95-percent. In this scenario, we estimate
that compliance with a requirement that process vents be 98-percent
controlled could result in reducing source category HAP emissions by
between 0.09 and 0.18 tpy from current emissions levels, with an
incremental cost effectiveness ranging between $1 million to $2
million/ton HAP reduction (section IV.D of this preamble provides
further discussion of the EPA's cost analysis). We estimate this option
would reduce the MIR at the MACT-allowable emissions level for the
source category from 1-in-1 million to 0.4-in-1 million, thus, would
reduce the number of people with cancer risks

greater than or equal to 1-in-1 million from 400 to 0. Although the
maximum chronic noncancer TOSHI was less than 1, this option would
further reduce it from 0.1 to 0.04. We are proposing that the
considerable cost of this option is not reasonable in light of the
minimal risk reduction achieved. Considering all of the health risks
and other health information considered in our determination of risk
acceptability, the minimal risk reductions associated with this option,
the uncertainty associated with the estimated potential risk
reductions, and the costs associated with this option, we are proposing
that additional HAP emissions controls for site remediation process
vents are not necessary to provide an ample margin of safety to protect
public health.
    For equipment leaks at affected sources, as discussed in section
IV.D of this preamble, we identified two emission control options:
Option 1 would require the use of the leak detection thresholds of 40
CFR part 63, subpart UU for valves and pumps, rather than the
thresholds of 40 CFR part 63, subpart TT; Option 2 would require the
same as Option 1 but would also include the connector LDAR requirements
of 40 CFR part 63, subpart UU. Since actual and MACT-allowable
emissions from equipment leaks are estimated to be the same, the risk
due to equipment leaks at the MACT-allowable level are estimated to be
the same as risk due to equipment leaks at actual emissions levels. In
addition, based on our analysis of estimated baseline equipment leak
emissions,\23\ we assumed that half of the equipment leak emissions are
from non-connector components (i.e., pumps and valves), and the other
half are from connectors. Under Option 1, we estimate the HAP reduction
would be 4.7 tpy from the baseline actual emissions level, with a cost
effectiveness of $2,000/ton HAP reduction. However, baseline risks
associated with equipment leaks are low, and there would be little
change in any of the risk metrics under Option 1. This option would
reduce the MIR from 1-in-1 million to 0.8-in-1 million, and reduce the
maximum chronic noncancer TOSHI from 0.1 to 0.08. In the context of our
ample margin of safety analysis, we are proposing that imposing this
option is not reasonable in light of the minimal risk reduction
achieved. Although this option is not required to provide an ample
margin of safety to protect public health, we are proposing this option
as a cost-effective development under our technology review. Under
Option 2 for equipment leaks, we estimate the incremental HAP reduction
would be 5 tpy more than Option 1, with an overall cost effectiveness
of $19,000/ton HAP reduction and a cost effectiveness incremental to
Option 1 of $35,000/ton HAP reduction. Similar to option 1, we found
that the control measure would provide little change to the estimated
risks, but at even higher cost. Therefore, we are proposing that the
cost of the Option 2 standards is not reasonable when weighed against
the minimal risk reduction achieved.
---------------------------------------------------------------------------

    \23\ See Technology Review and Cost Impacts for the Proposed
Amendments to the Off-Site Waste and Recovery Operations Source
Category, which is available in the docket for this action.
---------------------------------------------------------------------------

    In accordance with the approach established in the Benzene NESHAP,
the EPA weighed all health risk measures and information considered in
the risk acceptability determination, along with the costs of emissions
controls and technological feasibility, in making our ample margin of
safety determination. Considering the health risk information and the
little potential for risk reduction from control options identified for
this source category, as well as the high relative cost of that risk
reduction, we propose that the standards for the Site Remediation
source category provide an ample margin of safety to protect public
health. We request comments on the ample margin of safety analysis for
this source category.
3. Adverse Environmental Effect
    Considering the results of our environmental risk screening, we do
not expect an adverse environmental effect as a result of HAP emissions
from this source category, and we are proposing that it is not
necessary to set a more stringent standard to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect.

D. Additional Modeling for Site Remediation

    In addition to assessing risk from affected facilities, we also
conducted an inhalation risk assessment for all HAP emitted, a
multipathway screening assessment for the PB-HAP emitted, and an
environmental risk screening assessment for the PB-HAP and acid gases
(e.g., HCl) emitted from the CERCLA/RCRA exempt sources. Although
exempt from the regulatory requirements of the Site Remediation NESHAP,
these facilities are part of the Site Remediation source category. To
understand the risks from the facilities exempt from the Site
Remediation NESHAP requirements, these facilities were analyzed
separately for the purposes of the risk assessment. We present results
of the risk assessment briefly below and in more detail in the Residual
Risk Assessment for Exempt Sources in the Site Remediation Source
Category in Support of the 2019 Risk and Technology Review Proposed
Rule, which is available in the docket for this action.
1. Chronic Inhalation Risk Assessment Results
    The results of the chronic baseline inhalation cancer risk
assessment indicate that, based on estimates of current actual and
allowable emissions, the MIR posed by exempt sources in the Site
Remediation source category is 4-in-1 million driven by site
remediation model plant emissions of chromium (VI) compounds. The total
estimated cancer incidence based on actual and allowable emission
levels is 0.001 excess cancer cases per year, or 1 case every 1,000
years. The population exposed to cancer risks greater than or equal to
1-in-1 million considering actual and allowable emissions is 1,100 (see
Table 4 of this preamble). In addition, the maximum chronic noncancer
HI (TOSHI) is less than 1.

                                 Table 4--Site Remediation Sources Inhalation Risk Assessment Results for Exempt Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Estimated
                                                                Maximum         population at     Estimated annual                     Maximum screening
                 Number of facilities \1\                  individual cancer  increased risk of   cancer incidence   Maximum chronic    acute noncancer
                                                               risk (in 1      cancer >=1-in-1    (cases per year)   noncancer TOSHI           HQ
                                                                million)           million
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Based on Actual Emissions Level 2 3
                                                          ----------------------------------------------------------------------------------------------
118......................................................                  4              1,100              0.001                0.3                 <1
                                                          ----------------------------------------------------------------------------------------------
                                                                                Based on Whole Facility Emissions
                                                          ----------------------------------------------------------------------------------------------
                                                                       2,000          9,000,000                  1                  7  .................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from exempt sources in the source category.
\3\ Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks.

2. Screening Level Acute Risk Assessment Results
    As presented in Table 4 of this preamble, acute exposure to
emissions from exempt sources in the Site Remediation source category
result in a maximum HQ less than 1. For more detailed acute risk
results refer to the Residual Risk Assessment for Exempt Sources in the
Site Remediation Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule, which is available in the docket for
this action.
3. Multipathway Risk Screening Results
    The results of the multipathway risk screening assessment indicate
all Tier 2 screening values for PB-HAP emitted from exempt sources in
the source category (arsenic compounds, cadmium compounds, mercury
compounds, and POM) are less than 1. Based on these results, we are
confident that the cancer risks due to multipathway exposures to these
chemicals are lower than 1-in-1 million and the noncancer HIs are less
than 1.
    In the case of lead, the multipathway risks were assessed by
comparing modeled ambient lead concentrations against the primary NAAQS
for lead. The results of this analysis indicate that, based on actual
and allowable emissions, the maximum annual off-site ambient lead
concentration is 0.004 [micro]g/m\3\, well below the primary NAAQS of
0.15 [micro]g/m\3\.
4. Environmental Risk Screening Results
    The ecological risk screening assessment indicated all modeled
points were below the Tier 1 screening thresholds based on actual and
allowable emissions of PB-HAP (arsenic compounds, cadmium compounds,
mercury compounds, and POM) and acid gases (HCl and HF) emitted by
exempt sources in the source category.
    In the case of lead, the environmental risks were assessed by
comparing modeled ambient lead concentrations against the secondary
NAAQS for lead. The results of this analysis indicate that, based on
actual and allowable emissions, the maximum annual off-site ambient
lead concentrations were below the secondary NAAQS.
    Based on the results of the environmental risk screening
assessment, we would not expect environmental risks due to emissions
from these sources.
5. Facility-Wide Risk Results
    An assessment of whole-facility (or ``facility-wide'') risks was
performed as described above to characterize the exempt source risk in
the context of facility-wide risks.\24\ Facility-wide risks were
estimated using the NEI-based data. The maximum lifetime individual
cancer risk posed by the 118 facilities, based on facility-wide
emissions, is 2,000-in-1 million with ethylene oxide from facility-wide
flare emissions driving the risk. The total estimated cancer incidence
from the whole facility is one excess cancer case per year.
Approximately 9,000,000 people are estimated to have cancer risks above
1-in-1 million from facility-wide HAP emissions. Eleven facilities and
98,000 people have facility-wide lifetime individual cancer risk
greater than or equal to 100-in-1 million. Additional details on this
determination can be found in the Residual Risk Assessment for
Facilities Exempt from the Site Remediation Source Category in Support
of the 2019 Risk and Technology Proposed Rule, which is available in
the docket for this action.
---------------------------------------------------------------------------

    \24\ The facility-wide risk assessment includes all emission
points from exempt facilities within the Site Remediation source
category (including those for which there are no standards) as well
as other emission points covered by other NESHAP.
---------------------------------------------------------------------------

    Regarding the facility-wide risks from exempt facilities due to
ethylene oxide (described above), which are due to emission sources
that are not part of the Site Remediation source category, we intend to
evaluate those facility-wide estimated emissions and risks further and
may address these in a separate future action, as appropriate. In
particular, the EPA is addressing ethylene oxide based on the results
of the latest NATA released in August 2018, which identified the
chemical as a potential concern in several areas across the country.
(NATA is the Agency's nationwide air toxics screening tool, designed to
help the EPA and state, local, and tribal air agencies identify areas,
pollutants, or types of sources for further examination.) The latest
NATA estimates that ethylene oxide significantly contributes to
potential elevated cancer risks in some census tracts across the U.S.
(less than 1 percent of the total number of tracts). These elevated
risks are largely driven by an EPA risk value that was updated in late
2016. The EPA will work with industry and state, local, and tribal air
agencies as the EPA takes a two-pronged approach to address ethylene
oxide emissions: (1) Reviewing and, as appropriate, revising CAA
regulations for facilities that emit ethylene oxide--starting with air
toxics emissions standards for miscellaneous organic chemical
manufacturing facilities and commercial sterilizers; and (2) conducting
site-specific risk assessments and, as necessary, implementing emission
control strategies for targeted high-risk facilities. The EPA will post
updates on its work to address ethylene oxide on its website at:
https://www.epa.gov/ethylene-oxide.
    Regarding the noncancer risk assessment, the maximum chronic
noncancer HI associated with facility-wide emissions is estimated to be
7 due to chemical manufacturing wastewater treatment emissions of
chlorine. A total of eight facilities had a facility-wide

chronic noncancer HI greater than 1 due to emissions of one or more of
the following HAP: chlorine; 2,4-toluene diisocyanate; hexamethylene-
1,6-diisocyanate; acrolein; propionaldehyde; acetaldehyde; and
benzo[a]pyrene.
    As discussed in section VI.A.1 of this preamble, we are not
proposing requirements for facilities exempt from the emissions control
requirements of the Site Remediation NESHAP in this action.

E. What are the results and proposed decisions based on our technology
review?

    As described in section III.B of this preamble, our technology
review focused on identifying developments in practices, processes, and
control technologies for the emission sources in the Site Remediation
source category. To identify such developments since the MACT standards
were promulgated, we consulted the EPA's RBLC, reviewed subsequent
regulatory development efforts, reviewed major source operating permits
and minor and synthetic minor source operating permits, and reviewed
academic and trade literature for control technologies used in the
industry.
    For the Site Remediation source category, we did not identify any
developments in practices, processes, or control technologies for
storage tanks, containers, surface impoundments, oil-water separators,
organic-water separators, transfer systems, land treatment, or material
extraction activities beyond what is currently required in the rule.
For process vents and equipment leaks, we identified additional control
options, and the following sections summarize the results of our
technology review for these emissions sources.
    To perform the technology review, we needed information that was
not included in the RTR emissions dataset used for modeling site
remediation risks. Specifically, to evaluate the costs and cost
effectiveness of various control options, we used a model plant
approach for development of estimates for leaking components. This
model plant analysis is not comparable to the model plant approach used
in the risk analysis. The model plant for the technology review created
the basis for evaluating the options of revising the LDAR standards. We
model the number of potential leaking components, the leak rates
applicable to such plants, and the level of emissions from leaking
components under different standards. The component count and leak
rates are the basis for evaluating the relative costs and benefits of
changes that were considered for the LDAR program. Therefore, the model
plant approach we used resulted in baseline emission estimates
different from those included in the risk modeling dataset, which
included its own inventory of emissions due to leaks. Additional
information about our technology review and model plant approach can be
found in the memorandum titled CAA section 112(d)(6) Technology Review
for the Site Remediation Source Category, which is available in the
docket for this action.
1. Process Vents
    The current Site Remediation MACT standards at 40 CFR 63.7890
require emissions from process vents at existing and new affected
sources to be routed through a closed vent system to a control device
achieving at least 95-percent control. While some control devices, such
as carbon adsorption, are assumed to have a control efficiency of 95-
percent, other technologies are capable of achieving greater emissions
control, such as thermal oxidizers. Several of these devices have been
demonstrated to achieve a control efficiency of 98-percent or greater.
Based on the combination of reported control efficiencies for these
devices and known application to low concentration organic vapor gas
streams, we investigated the use of a catalytic thermal oxidizer with a
control efficiency of 98-percent as a potential control option.
    Table 5 presents the emission reductions and costs of the 98-
percent control option considered for process vents at existing
affected sources in the Site Remediation source category under the
technology review. Data collected through our search of title V permits
indicate that only some facilities have process vents, and based on
these data, we estimate that approximately six site remediation
facilities have process vents that would require additional control to
reduce emissions by 98 percent. As site remediations vary in the amount
and type of contamination that is being abated, we used two example
remediations to estimate the amount of HAP that could be removed
through the emissions controls. We estimated the capital and annual
costs of complying with an increase from 95- to 98-percent HAP control
for process vents to be the same for either example, with total capital
costs estimated at approximately $400,000 and the total annualized
costs estimated to be approximately $185,000. Based on the two example
facilities, the HAP emissions reduction beyond the current control
requirements could range between 0.09 and 0.18 tpy for the source
category, and the cost effectiveness could range from approximately
$31,000 to $66,000. The incremental cost effectiveness in going to 98-
percent control from 95-percent control could range from approximately
$1 million to $2 million per ton HAP removed.

                                       Table 5--Site Remediation Process Vent Option Emission Reductions and Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Incremental
                                                                          HAP  emissions                                       Cost            cost
                 Regulatory alternative                       Example        reduction     Capital cost     Annual cost    effectiveness   effectiveness
                                                             facility          (tpy)            ($)           ($/yr)        ($/ton HAP      ($/ton HAP
                                                                                removed)        removed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
98-percent control......................................               1            0.09         400,000         185,000          65,000       2,145,000
                                                                       2            0.18         400,000         185,000          30,000       1,000,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on our estimate of costs and HAP reduction, we do not
consider increasing the emission reduction to 98-percent to be
reasonable, and we are not proposing to revise the Site Remediation
MACT standards for process vents pursuant to CAA section 112(d)(6) to
require this level of emissions control. We solicit comment on our
analysis and conclusion regarding all aspects of this control option
(Comment C-3).
2. Equipment Leaks
    The Site Remediation MACT standards at 40 CFR 63.7920 currently
require compliance with either 40 CFR part 63, subpart TT, or 40 CFR
part 63, subpart UU, to control emissions from equipment leaks at
existing and new affected sources. While many provisions of these two
standards are the same or similar, 40 CFR part 63, subpart UU, requires
the use of a more stringent leak definition for valves in gas and vapor

service and in light liquid service, pumps in light liquid service, and
connectors. Specifically, 40 CFR part 63, subpart UU, lowers the leak
definition for valves from 10,000 ppm (in 40 CFR part 63, subpart TT)
to 500 ppm, lowers the leak definition for pump seals from 10,000 ppm
(in 40 CFR part 63, subpart TT) to 1,000 ppm, and requires periodic
instrument monitoring of connectors with a leak definition of 500 ppm,
as opposed to instrument monitoring only being required if a potential
leak is detected by visual, audible, olfactory, or other detection
method (in 40 CFR part 63, subpart TT). We identified the more
stringent leak definitions of 40 CFR part 63, subpart UU as a
development in practices, processes, or control technologies. The more
stringent definitions have, in the years since original promulgation of
the Site Remediation NESHAP in 2003, become widely adopted and are
frequently already required for sources in the Site Remediation source
category under the other applicable NESHAP requirements at these
sources. Making the more stringent level of leak detection more uniform
across a facility will also enhance regulatory consistency, clarity,
and certainty and enhance compliance.
    Assuming conservatively that each of the site remediation
facilities currently complies with 40 CFR part 63, subpart TT and does
not already comply with 40 CFR part 63, subpart UU, we analyzed the
costs and emission reductions of two options: Option 1--requiring the
use of the leak detection thresholds of 40 CFR part 63, subpart UU for
valves and pumps; Option 2--requiring the use of the leak detection
thresholds of 40 CFR part 63, subpart UU for valves and pumps and, in
addition, requiring connector monitoring under 40 CFR part 63, subpart
UU. The estimated costs and emissions reductions associated with these
two options for the site remediation source category are shown in Table
6. For Option 1 (40 CFR part 63, subpart UU valve and pump leak
detection thresholds), we estimated the capital costs to be
approximately $26,000 and the total annualized costs to be
approximately $10,000. The estimated HAP emissions reduction is
approximately 4.7 tpy, and the cost effectiveness is approximately
$2,000/ton. For Option 2 (40 CFR part 63, subpart UU valve and pump
leak detection thresholds and connector monitoring), we estimated the
capital costs to be approximately $95,000 and the total annualized
costs to be approximately $188,000. The estimated HAP emissions
reduction is approximately 9.7 tpy, and the cost effectiveness is
approximately $19,000/ton. The incremental cost effectiveness between
Option 1 and Option 2 is approximately $35,000.

                 Table 6--Site Remediation Equipment Leak Options Emission Reductions and Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Incremental
                                  HAP  emissions                                       Cost            cost
     Regulatory alternatives         reduction     Capital cost     Annual cost    effectiveness   effectiveness
                                       (tpy)            ($)           ($/yr)        ($/ton HAP      ($/ton HAP
                                                                                removed)        removed)
----------------------------------------------------------------------------------------------------------------
Option 1: 40 CFR part 63,                    4.7          26,000          10,000           2,000  ..............
 subpart UU valve and pump leak
 thresholds only................
Option 2: 40 CFR part 63,                    9.7          95,000         188,000          19,000          35,000
 subpart UU valve and pump leak
 detection thresholds and
 connector monitoring...........
----------------------------------------------------------------------------------------------------------------

    Based on our analysis, the costs of Option 1 are reasonable, given
the level of HAP emissions reduction that would be achieved with this
control option. We do not believe the costs of Option 2 are reasonable,
given the level of HAP emissions reduction it would achieve relative to
a much higher incremental cost per ton above Option 1. Therefore, we
are proposing to revise the Site Remediation MACT standards in
accordance with Option 1 for equipment leaks. We solicit comment on our
assessment and conclusions regarding all aspects of both options
(Comment C-4).

F. What other actions are we proposing?

    In addition to the proposed actions described above, we are
proposing additional revisions to the NESHAP, and requesting
information on two issues for which the EPA has been petitioned for
reconsideration. We are proposing revisions to the SSM provisions of
the MACT rule in order to ensure that they are consistent with the
Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008),
which vacated two provisions that exempted sources from the requirement
to comply with otherwise applicable CAA section 112(d) emission
standards during periods of SSM. We also are proposing various other
changes to require electronic reporting of emissions test results and
to make several minor technical corrections to the regulation text of
40 CFR part 63, subpart GGGGG. Our analyses and proposed changes
related to these issues are discussed below.
1. Standards for Inorganic HAP and Metal Emissions
    In the May 13, 2016, proposal on reconsideration, the EPA stated
that it would consider the issue of regulating metals and inorganic HAP
emissions during the risk review. 81 FR 29824. The EPA is proposing to
not set standards for metals and inorganic HAP from site remediation
sources subject to the Site Remediation NESHAP because we do not have
data indicating that remediation sources subject to the rule emit these
pollutants. In the EPA's development of the risk modeling emissions
data, we found six facilities with emissions data in the NEI that were
labeled under the SCC as being from a site remediation. None of these
facilities reported inorganic HAP emissions or metal emissions. The EPA
is, therefore, proposing no action at this time to set standards for
inorganic HAP and metals in the absence of data indicating such
emissions occur at affected facilities. The EPA is requesting data
demonstrating whether or not any affected site remediation sources emit
inorganic HAP or metals (Comment C-5).
2. SSM
a. Background
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the Court vacated portions of two provisions in the EPA's
CAA section 112 regulations governing the emissions of HAP during
periods of SSM. Specifically, the Court vacated the SSM exemption
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) holding that under
section 302(k) of the CAA, emissions standards or limitations must be
continuous in nature and that the SSM exemption violates the CAA's
requirement that a section 112 standard apply at all times.

    We are proposing to eliminate the SSM exemption in the Site
Remediation NESHAP. Consistent with Sierra Club v. EPA, we are
proposing standards in this rule that apply at all times. We are also
proposing several revisions to Table 3 (the General Provisions
Applicability Table) as is explained in more detail below. For example,
we are proposing to eliminate the incorporation of the General
Provisions' requirement that the source develop an SSM plan. We also
are proposing to eliminate and revise certain recordkeeping and
reporting requirements related to the SSM exemption as further
described below.
    The EPA has attempted to eliminate provisions that are
inappropriate, unnecessary, or redundant in the absence of the SSM
exemption in this proposal. We are specifically seeking comment on
whether we have successfully done so (Comment C-6).
    In proposing the standards in this rule, the EPA has taken into
account startup and shutdown periods and, for the reasons explained
below, has not proposed alternate standards for those periods.
    Based on the types of site remediation processes and equipment for
this source category, the EPA has assumed that emissions during periods
of startup and shutdown are the same as or lower than during normal
operations. As it is possible to stop processing remediation material
until any control devices are fully operating and able to effectively
control emissions, the EPA has determined that separate standards for
periods of startup and shutdown are not necessary and are not being
proposed. We solicit comment on this conclusion regarding periods of
startup and shutdown at site remediation facilities (Comment C-7).
    Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. However, by
contrast, malfunction is defined as a ``sudden, infrequent, and not
reasonably preventable failure of air pollution control and monitoring
equipment, process equipment or a process to operate in a normal or
usual manner. . .'' (40 CFR 63.2). The EPA has determined that CAA
section 112 does not require that emissions that occur during periods
of malfunction be factored into development of CAA section 112
standards. Under CAA section 112, emissions standards for new sources
must be no less stringent than the level ``achieved'' by the best
controlled similar source and for existing sources generally must be no
less stringent than the average emission limitation ``achieved'' by the
best performing 12 percent of sources in the category. There is nothing
in CAA section 112 that directs the EPA to consider malfunctions in
determining the level ``achieved'' by the best performing sources when
setting emission standards. As the Court has recognized, the phrase
``average emissions limitation achieved by the best performing 12
percent of sources'' says nothing about how the performance of the best
units is to be calculated. Nat'l Ass'n of Clean Water Agencies v. EPA,
734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts for
variability in setting emissions standards, nothing in CAA section 112
requires the EPA to consider malfunctions as part of that analysis. A
malfunction should not be treated in the same manner as the type of
variation in performance that occurs during routine operations of a
source. A malfunction is a failure of the source to perform in a
``normal or usual manner'' and no statutory language compels the EPA to
consider such events in setting standards based on ``best performers.''
    Further, accounting for malfunctions in setting emissions standards
would be difficult, if not impossible, given the myriad different types
of malfunctions that can occur across all sources in the category and
given the difficulties associated with predicting or accounting for the
frequency, degree, and duration of various malfunctions that might
occur. As such, the performance of units that are malfunctioning is not
``reasonably'' foreseeable. See, e.g., Sierra Club v. EPA, 167 F.3d
658, 662 (D.C. Cir. 1999) (``EPA typically has wide latitude in
determining the extent of data-gathering necessary to solve a problem.
We generally defer to an agency's decision to proceed on the basis of
imperfect scientific information, rather than to ``invest the resources
to conduct the perfect study.'' '') (internal quotation omitted). See
also Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (``In
the nature of things, no general limit, individual permit, or even any
upset provision can anticipate all upset situations. After a certain
point, the transgression of regulatory limits caused by `uncontrollable
acts of third parties,' such as strikes, sabotage, operator
intoxication or insanity, and a variety of other eventualities, must be
a matter for the administrative exercise of case-by-case enforcement
discretion, not for specification in advance by regulation.''). In
addition, the goal of a ``best controlled or best performing source''
is to operate in such a way as to avoid malfunctions of the source and
accounting for malfunctions could lead to standards that are
significantly less stringent than levels that are achieved by a well-
performing non-malfunctioning source. It is reasonable to interpret CAA
section 112 to avoid such a result. The EPA's approach to malfunctions
is consistent with CAA section 112 and is a reasonable interpretation
of the statute.
    In the event that a source fails to comply with the applicable CAA
section 112(d) standards as a result of a malfunction event, the EPA
would determine an appropriate response based on, among other things,
the good faith efforts of the source to minimize emissions during
malfunction periods, including preventative and corrective actions, as
well as root cause analyses to ascertain and rectify excess emissions.
The EPA would also consider whether the source's failure to comply with
the CAA section 112(d) standard was, in fact, ``sudden, infrequent, not
reasonably preventable'' and was not instead ``caused in part by poor
maintenance or careless operation.'' 40 CFR 63.2 (definition of
malfunction). Further, to the extent the EPA files an enforcement
action against a source for violation of an emission standard, the
source can raise any and all defenses in that enforcement action, and
the federal district court will determine what, if any, relief is
appropriate. The same is true for citizen enforcement actions.
Similarly, the presiding officer in an administrative proceeding can
consider any defense raised and determine whether administrative
penalties are appropriate.
    In several prior rules, the EPA had included an affirmative defense
to civil penalties for violations caused by malfunctions in an effort
to create a system that incorporates some flexibility, recognizing that
there is a tension, inherent in many types of air regulations, to
ensure adequate compliance, while simultaneously recognizing that
despite the most diligent of efforts, emission standards may be
violated under circumstances entirely beyond the control of the source.
Although the EPA recognized that its case-by-case enforcement
discretion provides sufficient flexibility in these circumstances, it
included the affirmative defense to provide a more formalized approach
and more regulatory clarity. Compare Weyerhaeuser Co. v. Costle, 590
F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an informal case-by-
case enforcement discretion approach is adequate) with Marathon Oil Co.
v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977) (requiring a more
formalized approach to consideration of ``upsets beyond the control of
the permit holder.''). Under

the EPA's regulatory affirmative defense provisions, if a source could
demonstrate in a judicial or administrative proceeding that it had met
the requirements of the affirmative defense in the regulation, civil
penalties would not be assessed. In 2014, the Court vacated such an
affirmative defense in one of the EPA's CAA section 112(d) regulations.
NRDC v. EPA, 749 F.3d 1055 (D.C. Cir. 2014) (vacating affirmative
defense provisions in a CAA section 112(d) rule establishing emission
standards for Portland cement kilns). The Court found that the EPA
lacked authority to establish an affirmative defense for private civil
suits and held that under the CAA, the authority to determine civil
penalty amounts lies exclusively with the courts, not the EPA.
Specifically, the Court found, ``As the language of the statute makes
clear, the courts determine, on a case-by-case basis, whether civil
penalties are `appropriate.' '' 749 F.3d at 1063; see also Id.
(``[U]nder this statute, deciding whether penalties are `appropriate'
in a given private civil suit is a job for the courts, not EPA.''). In
light of NRDC, the EPA is not including a regulatory affirmative
defense provision in this proposed rule. As explained above, if a
source is unable to comply with emissions standards as a result of a
malfunction, the EPA may use its case-by-case enforcement discretion to
provide flexibility, as appropriate. Further, as the Court recognized,
in an EPA or citizen enforcement action, the court has the discretion
to consider any defense raised and determine whether penalties are
appropriate. See Id. at 1064 (noting arguments that violation were
caused by unavoidable technology failure can be made to the courts in
future civil cases when the issue arises). The same logic applies to
EPA administrative enforcement actions.
b. Specific SSM-Related Proposed Changes
    To address the United States Court of Appeals for the District of
Columbia Circuit vacatur of portions of the EPA's CAA section 112
regulations governing the emissions of HAP during periods of SSM, we
are proposing revisions and additions to certain provisions of the Site
Remediation NESHAP. As described in detail below, we are proposing to
revise the General Provisions applicability table (Table 3 to 40 CFR
part 63, subpart GGGGG) in several of the references related to
requirements that apply during periods of SSM. We are also proposing
revisions related to the following provisions of the Site Remediation
NESHAP: (1) The general duty to minimize emissions at all times; (2)
the requirement for sources to comply with the emission limits in the
rule at all times; (3) performance testing conditions requirements; (4)
excused monitoring excursions provisions; and (5) malfunction
recordkeeping and reporting requirements.
(1.) General Duty
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.6(e) by adding rows specifically for 40 CFR
63.6(e)(1)(i), 63.6(e)(1)(ii), and 63.6(e)(1)(iii), and to include a
``no'' in the applicability column for the 40 CFR 63.6(e)(1)(i) entry.
Section 63.6(e)(1)(i) describes the general duty to minimize emissions.
Some of the language in that section is no longer necessary or
appropriate in light of the elimination of the SSM exemption. We are
proposing instead to add general duty regulatory text at 40 CFR
63.7935(b) that reflects the general duty to minimize emissions while
eliminating the reference to periods covered by an SSM exemption. The
current language in 40 CFR 63.6(e)(1)(i) characterizes what the general
duty entails during periods of SSM. With the elimination of the SSM
exemption, there is no need to differentiate between normal operations,
startup and shutdown, and malfunction events in describing the general
duty. Therefore, the language the EPA is proposing for 40 CFR
63.7935(b) does not include that language from 40 CFR 63.6(e)(1).
    We are also proposing to include a ``no'' in the applicability
column for the newly added entry for 40 CFR 63.6(e)(1)(ii). Section
63.6(e)(1)(ii) imposes requirements that are not necessary with the
elimination of the SSM exemption or are redundant with the general duty
requirement being added at 40 CFR 63.7935(b).
    The provisions of 40 CFR 63.6(e)(1)(iii) still apply, and we are
keeping the ``yes'' in the applicability column for that section. For
40 CFR 63.6(e)(2), we are proposing to include a ``no'' in the
applicability column for that section because it is a reserved section
in the General Provisions.
(2.) SSM Plan
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.6(e)(3) by changing the ``yes'' to ``no'' in the
applicability column. Generally, this paragraph requires development of
an SSM plan and specifies SSM recordkeeping and reporting requirements
related to the SSM plan. As previously noted, the EPA is proposing to
remove the SSM exemptions. Therefore, affected units will be subject to
an emission standard during such events. The applicability of a
standard during such events will ensure that sources have ample
incentive to plan for and achieve compliance and, thus, the SSM plan
requirements are no longer necessary.
(3.) Compliance With Standards
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in the
applicability column to a ``no.'' The current language of 40 CFR
63.6(f)(1) exempts sources from non-opacity standards during periods of
SSM. As discussed above, the Court in Sierra Club vacated the
exemptions contained in this provision and held that the CAA requires
that some CAA section 112 standard apply at all times. Consistent with
Sierra Club, the EPA is proposing to revise standards in this rule to
apply at all times.
(4.) Performance Testing
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in the
applicability column to a ``no.'' Section 63.7(e)(1) describes
performance testing requirements. The EPA is instead proposing to add a
performance testing requirement at 40 CFR 63.7941(b)(2). The
performance testing requirements we are proposing to add differ from
the General Provisions performance testing provisions in several
respects. The regulatory text does not include the language in 40 CFR
63.7(e)(1) that restated the SSM exemption. However, consistent with 40
CFR 63.7(e)(1), performance tests conducted under this subpart should
be based on representative performance (i.e., performance based on
normal operating conditions) of the affected source. The EPA is
proposing to add language that requires the owner or operator to record
the process information that is necessary to document operating
conditions during the test and include in such record an explanation to
support that such conditions represent normal operation. Section
63.7(e) requires that the owner or operator make available to the
Administrator such records ``as may be necessary to determine the
condition of the performance test'' upon request but does not
specifically require the information to be recorded. The regulatory
text the EPA is proposing to add to this provision builds on that
requirement and makes explicit the requirement to record and report the
information.

(5.) Monitoring
    We are proposing to revise the General Provisions table (Table 3)
entries for 40 CFR 63.8(c)(1)(i) and (iii) by changing the ``yes'' in
the applicability column to a ``no.'' The cross-references to the
general duty and SSM plan requirements in those subparagraphs are not
necessary in light of other requirements of 40 CFR 63.8 that require
good air pollution control practices (40 CFR 63.8(c)(1)) and that set
out the requirements of a quality control program for monitoring
equipment (40 CFR 63.8(d)).
(6.) Recordkeeping
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.10(b)(2)(i)-(iv) by adding separate entries for 40
CFR 63.10(b)(2)(i)-(ii), 63.10(b)(2)(iii) and 63.10(b)(2)(iv)-(v) and
changing the ``yes'' in the applicability column to a ``no'' for 40 CFR
63.10(b)(2)(i)-(ii) and 63.10(b)(2)(iv)-(v). Section 63.10(b)(2)(i)
describes the recordkeeping requirements during startup and shutdown.
These recording provisions are no longer necessary because the EPA is
proposing that recordkeeping and reporting applicable to normal
operations will apply to startup and shutdown. In the absence of
special provisions applicable to startup and shutdown, such as a
startup and shutdown plan, there is no reason to retain additional
recordkeeping for startup and shutdown periods. Section 63.10(b)(2)(ii)
describes the recordkeeping requirements during a malfunction. The EPA
is proposing to add such requirements to 40 CFR 63.7952(a)(2). The
regulatory text we are proposing to add differs from the General
Provisions it is replacing in that the General Provisions require the
creation and retention of a record of the occurrence and duration of
each malfunction of process, air pollution control, and monitoring
equipment. The EPA is proposing that this requirement apply to any
failure to meet an applicable standard and is requiring that the source
record the date, time, and duration of the failure rather than the
``occurrence.'' The EPA is also proposing to add to 40 CFR
63.7952(a)(2) a requirement that sources keep records that include a
list of the affected source or equipment and actions taken to minimize
emissions, an estimate of the volume of each regulated pollutant
emitted over the standard for which the source failed to meet the
standard, and a description of the method used to estimate the
emissions. Examples of such methods would include mass balance
calculations, measurements when available, or engineering judgment
based on known process parameters. The EPA is proposing to require that
sources keep records of this information to ensure that there is
adequate information to allow the EPA to determine the severity of any
failure to meet a standard, and to provide data that may document how
the source met the general duty to minimize emissions when the source
has failed to meet an applicable standard. Section 63.10(b)(2)(iv)
requires sources to record actions taken during SSM events when actions
were inconsistent with their SSM plan. The requirement is no longer
appropriate because SSM plans will no longer be required. The
requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to
record actions to minimize emissions and record corrective actions is
now applicable by reference to 40 CFR 63.7952(a)(2). Section
63.10(b)(2)(v) requires sources to record actions taken during SSM
events to show that actions taken were consistent with their SSM plan.
The requirement is no longer appropriate because SSM plans will no
longer be required.
(7.) Reporting
    We are proposing to revise the General Provisions table (Table 3)
entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in the
applicability column to ``no.'' Section 63.10(d)(5)(i) describes the
reporting requirements for startups, shutdowns, and malfunctions. To
replace the General Provisions reporting requirements, the EPA is
proposing to add electronic reporting requirements to 40 CFR
63.7951(c). The replacement language differs from the General
Provisions requirement in that it eliminates periodic SSM reports as a
stand-alone report. We are proposing language that requires sources
that fail to meet an applicable standard at any time to report the
information concerning such events in the semi-annual summary report
already required under this rule. We are proposing that the report must
contain the number, date, time, duration, and the cause of such events
(including unknown cause, if applicable), a list of the affected source
or equipment, an estimate of the quantity of each regulated pollutant
emitted over any emission limit, and a description of the method used
to estimate the emissions.
    Examples of such methods would include mass balance calculations,
measurements when available, or engineering judgment based on known
process parameters. The EPA is proposing this requirement to ensure
that there is adequate information to determine compliance, to allow
the EPA to determine the severity of the failure to meet an applicable
standard, and to provide data that may document how the source met the
general duty to minimize emissions during a failure to meet an
applicable standard.
    We will no longer require owners or operators to determine whether
actions taken to correct a malfunction are consistent with an SSM plan,
because plans would no longer be required. The proposed amendments,
therefore, eliminate the cross-reference to 40 CFR 63.10(d)(5)(i) that
contains the description of the previously required SSM report format
and submittal schedule from this section. These specifications are no
longer necessary because the events will be reported in otherwise
required reports with similar format and submittal requirements.
    Section 63.10(d)(5)(ii) describes an immediate report for startups,
shutdowns, and malfunctions when a source failed to meet an applicable
standard but did not follow the SSM plan. We will no longer require
owners and operators to report when actions taken during a startup,
shutdown, or malfunction were not consistent with an SSM plan, because
plans would no longer be required.
3. Electronic Reporting
    Through this proposal, the EPA is proposing that owners and
operators of site remediation facilities submit electronic copies of
required performance test reports, performance evaluation reports, and
semi-annual compliance reports through the EPA's Central Data Exchange
(CDX) using the Compliance and Emissions Data Reporting Interface
(CEDRI). A description of the electronic data submission process is
provided in the memorandum, Electronic Reporting Requirements for New
Source Performance Standards (NSPS) and National Emission Standards for
Hazardous Air Pollutants (NESHAP) Rules, available in Docket ID No.
EPA-HQ-OAR-2018-0833. The proposed rule requires that performance test
results collected using test methods that are supported by the EPA's
Electronic Reporting Tool (ERT) as listed on the ERT website \25\ at
the time of the test be submitted in the format generated through the
use of the ERT and that other performance test results be submitted in
portable document format (PDF) using the attachment module of

the ERT. Similarly, performance evaluation results of CMS measuring
relative accuracy test audit pollutants that are supported by the ERT
at the time of the test must be submitted in the format generated
through the use of the ERT and other performance evaluation results be
submitted in PDF using the attachment module of the ERT.
---------------------------------------------------------------------------

    \25\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For semi-annual summary compliance reports, the proposed rule
requires that owners and operators use the appropriate spreadsheet
template to submit information to CEDRI. A draft version of the
proposed template for this report is included in the docket for this
rulemaking.\26\ The EPA specifically requests comment on the content,
layout, and overall design of the template.
---------------------------------------------------------------------------

    \26\ See
40_CFR_Part_63_Subpart_GGGGG_Site_Remediation_Spreadsheet_Template_Dr
aft.xlsm, available at Docket ID No. EPA-HQ-OAR-2018-0833.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in
which electronic reporting extensions may be provided. In both
circumstances, the decision to accept the claim of needing additional
time to report is within the discretion of the Administrator, and
reporting should occur as soon as possible. The EPA is providing these
potential extensions to protect owners and operators from noncompliance
in cases where they cannot successfully submit a report by the
reporting deadline for reasons outside of their control. The situation
where an extension may be warranted due to outages of the EPA's CDX or
CEDRI which precludes an owner or operator from accessing the system
and submitting required reports is addressed in 40 CFR 63.7951(e). The
situation where an extension may be warranted due to a force majeure
event, which is defined as an event that will be or has been caused by
circumstances beyond the control of the affected facility, its
contractors, or any entity controlled by the affected facility that
prevents an owner or operator from complying with the requirement to
submit a report electronically as required by this rule is addressed in
40 CFR63.7951(e). Examples of such events are acts of nature, acts of
war or terrorism, or equipment failure or safety hazards beyond the
control of the facility.
    The electronic submittal of the reports addressed in this proposed
rulemaking will increase the usefulness of the data contained in those
reports, is in keeping with current trends in data availability and
transparency, will further assist in the protection of public health
and the environment, will improve compliance by facilitating the
ability of regulated facilities to demonstrate compliance with
requirements, and by facilitating the ability of delegated state,
local, tribal, and territorial air agencies and the EPA to assess and
determine compliance, and will ultimately reduce burden on regulated
facilities, delegated air agencies, and the EPA. Electronic reporting
also eliminates paper-based, manual processes, thereby saving time and
resources, simplifying data entry, eliminating redundancies, minimizing
data reporting errors, and providing data quickly and accurately to the
affected facilities, air agencies, the EPA, and the public. Moreover,
electronic reporting is consistent with the EPA's plan \27\ to
implement Executive Order 13563 and is in keeping with the EPA's
Agency-wide policy \28\ developed in response to the White House's
Digital Government Strategy.\29\ For more information on the benefits
of electronic reporting, see the memorandum, Electronic Reporting
Requirements for New Source Performance Standards (NSPS) and National
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules,
available in Docket ID No. EPA-HQ-OAR-2018-0833.
---------------------------------------------------------------------------

    \27\ EPA's Final Plan for Periodic Retrospective Reviews, August
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \28\ E-Reporting Policy Statement for EPA Regulations, September
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \29\ Digital Government: Building a 21st Century Platform to
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

4. Open-Ended Valves and Lines
    The Site Remediation NESHAP in 40 CFR 63.7920(b) requires an owner
or operator to control emissions from equipment leaks according to the
requirements of either 40 CFR part 63, subpart TT, or 40 CFR part 63,
subpart UU. For open-ended valves and lines, both subpart TT in 40 CFR
63.1014(b)(1) and subpart UU in 40 CFR 63.1033(b)(1) require that the
open end be equipped with a cap, blind flange, plug, or second valve
that shall ``seal the open end.'' However, ``seal'' is not defined in
either subpart, leading to uncertainty for the owner or operator as to
whether compliance is being achieved. Inspections under the EPA's Air
Toxics LDAR initiative have provided evidence that while certain open-
ended lines may be equipped with a cap, blind flange, plug, or second
valve, these are not providing a ``seal'' as the EPA interprets the
term.\30\ In response to this uncertainty, we are proposing to amend 40
CFR 63.7920(b) to clarify what ``seal the open end'' means for open-
ended valves and lines. This proposed clarification explains that for
the purpose of complying with the requirements of 40 CFR 63.1014(b)(1)
(subpart TT), and 40 CFR 63.1033(b)(1) (subpart UU), open-ended valves
and lines are ``sealed'' by the cap, blind flange, plug, or second
valve if instrument monitoring of the open-ended valve or line
conducted according to EPA Method 21 of 40 CFR part 60, appendix A
indicates no readings of 500 ppm or greater.
---------------------------------------------------------------------------

    \30\ See Region V OEL Data for VV Rulemaking, available in the
docket for this action, available at Docket ID No. EPA-HQ-OAR-2018-
0833.
---------------------------------------------------------------------------

    In addition, 40 CFR 63.1014(c) of subpart TT and 40 CFR 63.1033(c)
of subpart UU exempt open-ended valves and lines that are in an
emergency shutdown system, and which are designed to open
automatically, from the requirements to be equipped with a cap, blind
flange, plug, or second valve that seals the open end. We are proposing
that these open-ended valves and lines follow the requirements of 40
CFR 63.7920(b)(3)(ii) for bypass devices that could be used to divert a
vent stream from the closed-vent system to the atmosphere, which would
require that each such open-ended line be equipped with either a flow
indicator or a seal or locking device. We are also proposing
recordkeeping and reporting requirements in 40 CFR 63.7951(g)(3) and 40
CFR 63.7952(a)(2)(v)(B) for these open-ended values and lines.
    We solicit comments on our proposed approach to reducing the
compliance uncertainty associated with ``sealed'' open-ended valves and
lines and our proposed requirements for open-ended valves and lines
that are in an emergency shutdown system and are designed to open
automatically (Comment C-8).
5. Technical Corrections
    In this rulemaking, we are proposing four technical corrections to
improve the clarity of the Site Remediation NESHAP requirements.
    First, the original Site Remediation NESHAP, promulgated in October
2003 (68 FR 58172), incorporated two voluntary consensus standards
(VCS) by reference, as specified in 40 CFR 63.14. However, while the
paragraphs in 40 CFR 63.14 for these three VCS include references to
the NESHAP for which they are approved to be used, these references
omit citations to 40 CFR 63, subpart GGGGG. In 40 CFR 63.14, we

are adding citations to 40 CFR 63.7944 for the two following consensus
standards: American Petroleum Institute (API) Publication 2517,
Evaporative Loss From External Floating-Roof Tanks, and American
Society for Testing and Materials (ASTM) Method D2879-83.
    Second, we are correcting a citation reference to 40 CFR 63.7(3) in
40 CFR 63.7942. The correct citation is to 40 CFR 63.7(a)(3).
    Third, we are correcting a citation reference to 40 CFR
63.7890(a)(1)(i) in 40 CFR 63.7941. The correct citation is to 40 CFR
63.7890(b).
    Fourth, we are correcting several citation references to 40 CFR
63.7990 in 40 CFR 63.7901(a), 40 CFR 63.7901(b)(1), and 40 CFR
63.7903(a) and (b). The correct citations are to 40 CFR 63.7900.

G. What compliance dates are we proposing?

    Under CAA section 112(d), the proposed compliance date for new and
existing affected sources for the revised SSM requirements, electronic
reporting requirements, the operating and pressure release management
requirements for PRDs, and the revised requirements regarding bypasses
and closure devices on pressure tanks is the effective date of the
final amendments. We are proposing this compliance date because
available information indicates these new and revised requirements
should be immediately implementable by the facilities.
    We are proposing that for existing affected sources subject to the
Site Remediation MACT standards, the compliance date for the PRD
pressure release actuation event reporting requirements is 1 year from
the effective date of the final amendments. This time is needed
regardless of whether an owner or operator of a facility chooses to
comply with the PRD pressure release actuation event reporting
provisions by installing PRD release indicator systems, employing
parameter monitoring, routing releases to a control device, or choosing
another compliance option as permitted under the proposed provisions.
This time period will allow site remediation facility owners and
operators to research equipment and vendors, and to purchase, install,
test, and properly operate any necessary equipment by the compliance
date. For new affected sources, the proposed compliance date for PRD
pressure release actuation event reporting requirements is the
effective date of the final amendments.
    Finally, we are proposing revised requirements for equipment leaks
under CAA section 112(d)(6). The EPA generally understands the steps
needed for site remediation facilities to comply with the proposed
standards for equipment leaks, and believes 1 year represents a
reasonable amount of time it will take these facilities to take these
steps. Therefore, we are proposing that a one-year compliance period
from the date of promulgation is necessary for the revised equipment
leak requirements to allow existing affected sources that are currently
complying with 40 CFR part 63, subpart TT, adequate time to modify
their existing LDAR programs to comply with the revised standards for
pumps and valves. For new affected sources, the proposed compliance
date for the equipment leak standards is the effective date of the
final amendments.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    We estimate that there are approximately 63 major source site
remediation facilities. Based on available permit information, 33
facilities are expected to be subject to a limited set of the rule
requirements under 40 CFR 63.7881(c)(1) due to the low annual quantity
of HAP contained in the remediation material excavated, extracted,
pumped, or otherwise removed during the site remediations conducted at
the facilities. These facilities are only required to prepare and
maintain written documentation to support the determination that the
total annual quantity of the HAP contained in the remediation material
excavated, extracted, pumped, or otherwise removed at the facility is
less than 1 megagram per year. They are not subject to any other
emissions limits, work practices, monitoring, reporting, or
recordkeeping requirements. While new site remediations are likely to
be conducted in the future, we are currently not aware of any specific
new site remediation facilities that are expected to be constructed.

B. What are the air quality impacts?

    For equipment leaks, we are proposing to revise the equipment leak
thresholds for pumps and valves for facilities complying with 40 CFR
part 63, subpart TT. We estimate the HAP emission reduction for this
change to be approximately 4.7 tpy. We do not anticipate any HAP
emission reduction from our proposed clarification of the rule
provision ``seal the open end'' (in the context of open-ended valves
and lines) or the requirement to electronically report the results of
emissions testing. For the proposed revisions to the MACT standards
regarding SSM, including monitoring of PRDs in remediation material
service, we were not able to quantify the possible emission reductions,
so none are included in our assessment of air quality impacts.
    Therefore, the estimated total HAP emission reductions for the
proposed rule revisions for the Site Remediation source category are
estimated to be 4.7 tpy.

C. What are the cost impacts?

    For equipment leaks, we are proposing to revise the equipment leak
thresholds for pumps and valves for facilities complying with 40 CFR
part 63, subpart TT. We estimate the nationwide capital costs to be
$26,000 and the annual costs to be $10,000.
    We do not anticipate any quantifiable capital or annual costs for
our proposed requirements to electronically report the results of
emissions testing, or the requirements to monitor PRDs. For PRDs, we
are also proposing to require facilities to conduct analyses of the
causes of PRD pressure release actuation events and to implement of
corrective measures. We estimate the nationwide annualized costs for
the analysis of actuation events to be $13,000. This cost represents
the estimated labor hours we anticipate would be required to determine
the cause of a typical actuation event and to implement any corrective
measure suggested by the analysis of the cause. We estimate an increase
in reporting and recordkeeping associated with the proposed
requirements for equipment leaks and PRDs of approximately $7,000 per
year nationwide. Therefore, the total capital costs for the proposed
standards for the Site Remediation source category are approximately
$26,000, and the total annualized costs are approximately $30,000.

D. What are the economic impacts?

    Economic impact analyses focus on changes in market prices and
output levels. If changes in market prices and output levels in the
primary markets are significant enough, impacts on other markets may
also be examined. Both the magnitude of costs needed to comply with a
proposed rule and the distribution of these costs among affected
facilities can have a role in determining how the market will change in
response to a proposed rule. The total capital costs associated with
this proposed rule are estimated to be approximately $26,000, and the
estimated annualized cost is approximately $30,000. We expect these
costs to be borne by 30 facilities, with

an estimated annualized cost of approximately $1,000 per facility per
year. These costs are not expected to result in a significant market
impact, regardless of whether they are passed on to the purchaser or
absorbed by the firms.

E. What are the benefits?

    We have estimated that this action will achieve HAP emissions
reductions of 4.7 tpy. The proposed standards will result in reductions
in the actual and MACT-allowable emissions of HAP and may reduce the
actual and potential cancer risks and noncancer health effects due to
emissions of HAP from this source category, as discussed in section
IV.B.2 of this preamble. We have not quantified the monetary benefits
associated with these reductions; however, these avoided emissions will
result in improvements in air quality and reduced negative health
effects associated with exposure to air pollution of these emissions.

VI. Request for Comment

A. Request for Comment Regarding CERCLA/RCRA Exempt Sources

1. Introduction
    The EPA is using this RTR proposal separately to solicit comment on
ways in which the Site Remediation NESHAP could be amended with respect
to facilities currently exempt under 40 CFR 63.7881(b)(2) and (3),
under a scenario where the EPA removes the exemption. The exemption
applies to facilities subject to federally-enforceable oversight under
the CERCLA or the RCRA. In particular, in light of comments received on
our 2016 proposal to remove the exemption, the Agency seeks additional
comment regarding subcategorization or other methods of distinguishing
among appropriate requirements for such sources, as well as whether the
issues raised by commenters may be applicable more generally for all
affected facilities in this source category. The EPA is seeking comment
on how, if the exemption was removed, these formerly exempt sources
would be able to implement the Site Remediation NESHAP effectively and
efficiently while meeting the requirements of RCRA, CERCLA, and the
CAA. We seek comment on how this could be reflected in the
applicability, monitoring, recordkeeping, reporting, and compliance
demonstration requirements. The EPA seeks comment on how to efficiently
implement the rule for cleanups conducted under CERCLA or RCRA
authority. For example, this could include look-up tables for commonly
used remediation alternatives and associated BACT and LAER compliant
technologies that would minimize emissions to be consistent with the
rule. We are seeking ideas on what tools or metrics could be developed
that would aid to streamline the implementation of the regulation on a
site-specific basis.
    It is not the EPA's intention to take final action with respect to
the exemption in this action, but to use this opportunity to gather
additional information in anticipation of addressing these issues
through a separate action (Comment C-9).
2. Background
    Section 112(c)(1) of the CAA requires EPA to publish and regularly
update (at least every 8 years) ``a list of all categories and
subcategories of major sources and area sources (listed under paragraph
(3)) of the air pollutants listed pursuant to subsection (b).'' In
1992, the EPA included site remediation on the initial CAA 112(c)(1)
source category list and defined the source category to include the
cleanup of sites that possess contaminated media, including National
Priorities List sites and Corrective Action sites. See the EPA, July
1992 Final Report. The listing assumed that remediation cleanups
conducted under specific cleanup authorities could be major sources.
Section 112(c)(2) of the CAA states that the EPA ``shall establish
emissions standards under [section 112(d)]'' for the categories and
subcategories the Administrator lists. The D.C. Circuit has described
this as a mandatory obligation. See, e.g., NRDC v. EPA, 489 F.3d. 1364,
1368 (2007).
3. Promulgation of Rule and Petition for Reconsideration
    In 2003, the EPA promulgated a final rule under CAA section 112
which established MACT standards for HAP emissions at major sources
where remediation technologies and practices are used to clean up
contaminated media (e.g., soils, groundwater, or surface water) or
certain stored or disposed materials (68 FR 58172, October 8, 2003).
The rule exempted from the MACT standard remediations performed under
federal oversight pursuant to CERCLA or the RCRA corrective action
program, on the basis that such regulated cleanups provided the
``functional equivalent'' of the MACT standards. Id. at 58176.
    The EPA stated that CERCLA Superfund and RCRA corrective action
programs provide an ``appropriate and effective regulatory approach''
to address air emissions, because these statutes require consideration
of the same HAP emissions and include a public input process. Id. at
58183. EPA noted the RCRA corrective action and CERCLA Superfund
assessment and clean-up processes are already subject to federal
regulatory oversight; further, remediation actions are designed and
managed based on site-specific conditions; and, they include public
participation mechanisms. Id. Note that the EPA did not extend the RCRA
and CERCLA exemption to sites handled under state and voluntary cleanup
programs, brownfields cleanups, and other types of site remediation
that are not subject to the oversight provided for RCRA corrective
action or CERCLA Superfund actions, see Id. at 58183-84. The EPA
concluded that imposing the NESHAP requirements on remediations already
overseen pursuant to CERCLA or RCRA would have limited impact and could
add administrative burden to the remediation process under those
programs for little or no environmental benefit. Id.
    The Sierra Club filed a petition for judicial review of the rule in
the Court as well as an administrative petition for reconsideration
under the CAA on two issues in the final rule, one of which was the
exemption for CERCLA and RCRA sites. The other issue raised by
petitioners concerned control of heavy metals and other inorganic HAP
from this source category. This issue is addressed in section IV.E.1 of
this preamble. The petition for reconsideration stated that the public
did not have an opportunity to comment specifically on the EPA's
``functional equivalent'' argument because the EPA raised it for the
first time in the final rule preamble. Petitioners further stated that
there is no CAA authority to exempt these sources, and CAA section
112(c) and (d) require that the EPA establish MACT standards for them.
Petitioners asserted that CERCLA and RCRA applicable requirements are
not the functional equivalent of the MACT standards for this source
category, and that the EPA had not demonstrated that they are.
    In January 2004, the Court granted a joint motion to hold the case
in abeyance so the parties could discuss possible settlement.
Settlement discussions were ultimately unsuccessful. In October 2014,
the Court ordered the parties to show cause why the case should not be
administratively terminated. The EPA and Sierra Club filed a joint
response stating that the parties were exploring a new approach to
settlement. In March 2015, the EPA granted reconsideration on the
issues raised in the petition via letter.

    In May 2016, the EPA proposed to remove the exemption from the Site
Remediation MACT rule for CERCLA Superfund and RCRA corrective action
sites (81 FR 29821 May 13, 2016). The EPA has not taken final action on
the proposed rule, and the EPA now is seeking further comment and
information relating to this issue.
4. 2016 Proposal on Reconsideration
    On May 13, 2016, the EPA proposed to amend the Site Remediation
NESHAP by removing exemptions from the rule for site remediation
activities performed under federally-enforceable oversight authority of
CERCLA or RCRA. 81 FR 29821.The EPA also proposed removing the
applicability requirement that site remediations be co-located with at
least one other stationary source regulated by another NESHAP. The EPA
has not taken final action on that proposal and is not proposing to do
so in this notice. However, in conjunction with this proposal for the
RTR, the EPA is seeking additional comment and information related to
the EPA's previous proposal to remove the exemptions for remediations
under RCRA and CERCLA programs. The EPA is not seeking further comment
on the proposal to remove the applicability requirement that site
remediations be co-located with at least one other stationary source
regulated by another NESHAP.
    In response to our 2016 proposal, the EPA received comments both in
support of and in opposition to our proposal to remove the exemption
provisions. The EPA has reviewed the comments received in response to
our 2016 proposal and does not believe it has sufficient information to
proceed with a final rule at this time. The comments received in
opposition to the proposal to remove the exemptions suggested that the
proposal to remove the RCRA and CERCLA exemptions alone, without
further consideration of modification of other provisions, may apply
the NESHAP to sources that we did not intend to regulate, or apply the
NESHAP in a way that compliance is impractical given the nature of the
remediation effort facing the source.
    These comments, briefly summarized below (and available in the
proposal docket at EPA-HQ-OAR-2002-0021), have led the EPA to determine
that additional information and comment are appropriate before taking
further action. The EPA is not proposing any regulatory action on
removing the RCRA and CERCLA exemptions in this RTR proposal. Rather,
the EPA is using this proposal as an opportune time to solicit further
information and data in response to the comments on our prior proposal.
The comments and information we receive with respect to the exemptions
will be added to the information available for a subsequent rulemaking
after the EPA has finalized the RTR.
5. Discussion and Request for Comment
    The 2016 proposal to eliminate the exemption included no other
changes to the rule, although the proposal would have the effect of
applying the rule to approximately 125 facilities at which a site
remediation is conducted, an inclusion that would, in turn, cover an
even greater number of operable units. The EPA received comments from
facilities from across the spectrum of exempt sources likely to be
subject to the rule after removing the exemptions. This broad range of
sources and their diversity indicate that the EPA should consider sub-
categorization or other methods of differentiating among sources under
the Site Remediation NESHAP.
    Under CAA section 112(c), the EPA may establish subcategories based
on size, type, or class of affected source, such that standards
applicable to each subcategory achieve reductions required by the CAA,
but in a manner appropriate to that subgroup of sources. In general,
the EPA has established subcategories based on the material inputs or
the nature of the products being produced which in turn inform the
nature of the requirements that apply. In other cases, the EPA created
subcategories for different process equipment that required air
pollution control of fundamentally different operating parameters and
mechanisms, and which, in turn, required monitoring or testing of
different types to demonstrate compliance.
    The EPA understands the comments on the May 2016 proposal to
indicate that the EPA should consider subcategorizing or
differentiating among remediations in some way. While the Site
Remediation NESHAP already reflects certain differences in remedial
actions, in commenters' view, there are other considerations that
warrant further consideration of how the rule is structured.
    Commenters described the site remediation in ways that suggested
that applying the Site Remediation NESHAP is unlike applying other
NESHAP. For example, when a typical major source is constructed, the
owner-operator is fully aware of the processes they will perform, the
equipment that will be needed, and the techniques and practices that
will be employed to comply with applicable standards. If a source is
not able to determine applicability based on their own comparison of
potentially applicable standards and their industrial processes, the
facility can request an applicability determination from the EPA.
    In contrast, an entity that is initiating a site remediation must
contend with a level of uncertainty and incomplete information about
the remediation that eventually will occur. These differences have a
material impact on the way sources determine applicability and
implement specific provisions of the Site Remediation NESHAP. For
example, 40 CFR 63.7886(c)(1) has provisions that require that a source
conduct a site investigation to substantiate specific subsurface
quantities of pollutants to be remediated, to determine whether a given
remediation will be subject to the rule.
    To make this determination, the extent of contamination must be
estimated, but these quantities may not be known until a future (and
often extended) period for a single operable unit. This is further
complicated when a facility consists of many individual operable units
dispersed over hundreds of acres. A facility with a series of operable
units that will be in remediation in sequence is not required to know
the pollutant quantities at all operable units at the outset of the
first remediation, unless the facility is compelled to make an
applicability determination under the Site Remediation NESHAP. When
remediating a series of operable units, the remediation activity across
units may not be active at the same time or may be intermittent or
discontinued after a couple of months or years. This makes an
applicability determination for a potentially affected source a greater
hurdle than the EPA may have considered.
    The EPA recognizes that the diversity of sites already subject to
the NESHAP is a characteristic of the Site Remediation source category
as a whole. However, we understand commenters' view to be that the size
of the cleanup, and the typically greater scale, complexity, and
diversity of remediation issues at sites that fall under the current
RCRA and CERCLA exemption render the considerations discussed above
particularly significant in establishing appropriate NESHAP
requirements for such sites.
    Another consideration highlighted by commenters for these typically
large and complex remediation sites is that remediation is driven by
the requirements of the RCRA and CERCLA programs, not by compliance
with a NESHAP. For some affected sources, according to commenters,
compliance

with certain requirements of the rule may have a negative impact on the
execution of remediation conducted in compliance with RCRA and CERCLA.
For example, RCRA and CERCLA cleanups may be ongoing at the time that
the remediation becomes subject to the Site Remediation NESHAP. While
the EPA has some flexibility in the applicability date of the NESHAP,
commenters pointed out that the EPA provided no regulatory language to
guide a facility to show whether or how the facility's adherence to
corrective action requirements and approved remediation plans under
RCRA and CERCLA demonstrate initial or continuing compliance with the
Site Remediation NESHAP standards to allow a remediation to proceed.
    The EPA will take these comments under advisement, to be acted upon
at a later date. The EPA will proceed with the RTR notice and comment
rulemaking to complete this requirement under CAA section 112 by the
deadline. Please see sections IV.B and IV.D of this preamble, and
technical support documents supplied in the docket, for how the EPA has
evaluated exempt sources with respect to both the risk and technology
reviews.

B. Request for Comment on All Aspects of the Risk and Technology Review

    We solicit comments on all aspects of this proposed action. In
addition to general comments on this proposed action, we are also
interested in additional data that may improve the risk assessments and
other analyses. We are specifically interested in receiving any
improvements to the data used in the site-specific emissions profiles
used for risk modeling. Such data should include supporting
documentation in sufficient detail to allow characterization of the
quality and representativeness of the data or information. Section VII
of this preamble provides more information on submitting data.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category
risk and demographic analyses and instructions are available for
download on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are
inaccurate, please identify the data in question, provide your reason
for concern, and provide any ``improved'' data that you have, if
available. When you submit data, we request that you provide
documentation of the basis for the revised values to support your
suggested changes. To submit comments on the data downloaded from the
RTR website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested
revision (i.e., commenter name, commenter organization, commenter email
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in
Microsoft[supreg] Access format and all accompanying documentation to
Docket ID No. EPA-HQ-OAR-2018-0833 (through the method described in the
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple
facilities, you need only submit one file for all facilities. The file
should contain all suggested changes for all sources at that facility
(or facilities). We request that all data revision comments be
submitted in the form of updated Microsoft[supreg] Excel files that are
generated by the Microsoft[supreg] Access file. These files are
provided on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is not a significant regulatory action and was,
therefore, not submitted to OMB for review.

B. Executive Order 13771: Reducing Regulation and Controlling
Regulatory Costs

    This action is not expected to be an Executive Order 13771
regulatory action because this action is not significant under
Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have
been submitted for approval to OMB under the PRA. The Information
Collection Request (ICR) document that the EPA prepared has been
assigned EPA ICR number 2062.07. You can find a copy of the ICR in the
docket for this rule, and it is briefly summarized here.
    The information requirements in this rulemaking are based on the
notification, recordkeeping, and reporting requirements in the NESHAP
General Provisions (40 CFR part 63, subpart A), which are mandatory for
all operators subject to national emission standards. These
notifications, reports, and records are essential in determining
compliance, and are specifically authorized by CAA section 114 (42
U.S.C. 7414). All information submitted to the EPA pursuant to the
recordkeeping and reporting requirements for which a claim of
confidentiality is made is safeguarded according to agency policies set
forth in 40 CFR part 2, subpart B.
    Respondents/affected entities: Unlike a specific industry sector or
type of business, the respondents potentially affected by this ICR
cannot be easily or definitively identified. Potentially, the Site
Remediation rule may be applicable to any type of business or facility
at which a site remediation is conducted to clean up media contaminated
with organic HAP when the remediation activities are performed, the
authority under which the remediation activities are performed, and the
magnitude of the HAP in the remediation material meets the
applicability criteria specified in the rule. A site remediation that
is subject to this rule potentially may be conducted at any type of
privately-owned or government-owned facility at which contamination has
occurred due to past events or current activities at the facility. For
site remediation performed at sites where the facility has been
abandoned and there is no owner, a government agency takes
responsibility for the cleanup.
    Respondent's obligation to respond: Mandatory (42 U.S.C. 7414).
    Estimated number of respondents: 30 total for the source category.
These facilities are already respondents and no facilities are expected
to become respondents as a result of this proposed action.
    Frequency of response: Semiannual.
    Total estimated burden: 19,700 total hours (per year) for the
source category, of which 310 hours are estimated as a result of this
proposed action. Burden is defined at 5 CFR 1320.3(b).
    Total estimated cost: The total estimated cost of the rule is $1.39
million (per year) for the source category. This includes $126,000
total annualized capital or operation and maintenance costs. We
estimate that $36,000 of the $126,000 in total annualized capital or
operation and

maintenance costs is a result of this proposed action. Recordkeeping
and reporting costs of approximately $7,000 estimated as a result of
this action are included in the $1.39 million in total costs.
    An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to<EMAIL_ADDRESS>Attention: Desk Officer for the
EPA. Since OMB is required to make a decision concerning the ICR
between 30 and 60 days after receipt, OMB must receive comments no
later than October 3, 2019. The EPA will respond to any ICR-related
comments in the final rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. The
small entities subject to the requirements of this action are chemical
and refining companies. The Agency has determined that two small
entities, representing approximately 7 percent of the total number of
entities subject to the proposal, may experience an impact of less than
0.1 percent of revenues. Details of this analysis are presented in the
docket for this action (Docket ID No. EPA-HQ-OAR-2018-0833).

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments. This proposed rule
imposes no enforceable duty on any state, local, or tribal governments,
or the private sector.

F. Executive Oder 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This action does not have tribal implications, as specified in
Executive Order 13175 (65 FR 67249, November 9, 2000). There are no
site remediation facilities that are owned or operated by tribal
governments. Thus, Executive Order 13175 does not apply to this action.
The EPA specifically solicits comment on this proposed action from
tribal officials.

H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is
not economically significant as defined in Executive Order 12866, and
because the EPA does not believe the environmental health or safety
risks addressed by this action present a disproportionate risk to
children. Because the proposed rule amendments would result in reduced
emissions of HAP and reduced risk to anyone exposed, the EPA believes
that the proposed rule amendments would provide additional protection
to children. More information on the source category's risk can be
found in section IV of this preamble. The complete risk analysis
results and the details concerning its development are presented in the
memorandum entitled Residual Risk Assessment for the Site Remediation
Source Category in Support of the 2019 Risk and Technology Review
Proposed Rule, available in the docket for this action (Docket ID No.
EPA-HQ-OAR-2018-0833).
    The public is invited to submit comments or identify peer-reviewed
studies and data that assess effects of early life exposure to HAP
emitted by site remediation facilities.

I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR
Part 51

    This action involves technical standards. The EPA is formalizing
the incorporation of two technical standards that were included in the
October 2003 rule for which the EPA had previously not formally
requested the Office of the Federal Register to include in 40 CFR 63.14
with a reference back to the sections in 40 CFR 63, subpart GGGGG.
These two standards were already incorporated in 40 CFR 63.14 and were
formally requested for other rules. These standards are API Publication
2517, ``Evaporative Loss from External Floating-Roof Tanks,'' Third
Edition, February 1989, and ASTM D2879-83, ``Standard Method for Vapor
Pressure- Temperature Relationship and Initial Decomposition
Temperature of Liquids by Isoteniscope.'' The API Publication 2517 is
used to determine the maximum true vapor pressure of HAP in liquids
stored at ambient temperature and is available to the public for free
viewing online in the Read Online Documents section on API's website at
https://publications.api.org. In addition to this free online viewing
availability on API's website, hard copies and printable versions are
available for purchase from API. The ASTM D2879-83 method is also used
to determine the maximum true vapor pressure of HAP in liquids stored
at ambient temperature, and it is available to the public for free
viewing online in the Reading Room section on ASTM's website at https://www.astm.org/READINGLIBRARY/. Hardcopies and printable versions are
also available for purchase from ASTM. Additional information can be
found at http://www.api.org/and https://www.astm.org/Standard/standards-andpublications.html.

K. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    The EPA believes that this action does not have disproportionately
high and adverse human health or environmental effects on minority
populations, low-income populations and/or indigenous peoples, as
specified in Executive Order 12898 (59 FR 7629, February 16, 1994)
because it increases the level of environmental protection for all
affected populations without having any disproportionately high and
adverse human health or environmental effects on any population,
including any minority, low income, or indigenous populations.
    To gain a better understanding of the source category and near
source populations, the EPA conducted a demographic analysis for site
remediation facilities to identify any overrepresentation of minority,
low income, or indigenous populations with cancer risks above 1-in-1
million. This analysis only gives some indication of the prevalence of
sub-populations that may be exposed to air pollution from the sources;
it does not identify the demographic characteristics of the most

highly affected individuals or communities, nor does it quantify the
level of risk faced by those individuals or communities. More
information on the source category's risk can be found in section IV of
this preamble. The complete demographic analysis results and the
details concerning its development are presented in the memorandum
titled Risk and Technology Review--Analysis of Demographic Factors for
Populations Living Near Site Remediation Source Category Operations,
available in the docket for this action (Docket ID No. EPA-HQ-OAR-2018-
0833).
    For the Site Remediation source category, the demographic analysis
revealed that for some demographic categories, the percentage of people
with cancer risks greater than or equal to 1-in-1 million is above
their corresponding national averages of the amount of people in that
demographic category. These demographic categories are ``African
American,'' ``Above Poverty Level,'' and ``Over 25 and With a High
School Diploma.'' The ratio of African Americans with a cancer risk
greater than or equal to 1-in-1 million due to site remediation is 17
percent higher than the national average percentage of people in that
demographic category (14 percent versus 12 percent); the ratio of
people living above the poverty line with a cancer risk greater than or
equal to 1-in-1 million due to site remediation is 1 percent higher
than the national average percentage of people in that demographic
category (87 percent versus 86 percent); and the ratio of people over
age 25 with a high school diploma with a cancer risk greater than or
equal to 1-in-1 million due to site remediation is 3 percent higher
than the national average percentage of people in that demographic
category (89 percent versus 86 percent). However, as noted previously,
risks from this source category were found to be acceptable for all
populations.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous
substances, Incorporation by reference, Reporting and recordkeeping
requirements.

     Dated: August 5, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the EPA proposes to
amend 40 CFR part 63 as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
FOR SOURCE CATEGORIES

0
1. The authority citation for part 63continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

0
2. Section 63.14 is amended by revising paragraphs (c)(1) and (h)(31)
to read as follows:

Sec.  63.14  Incorporations by reference.

* * * * *
    (c) * * *
    (1) API Publication 2517, Evaporative Loss from External Floating-
Roof Tanks, Third Edition, February 1989, IBR approved for Sec. Sec.
63.111, 63.1402, 63.2406 and 63.7944.
* * * * *
    (h) * * *
    (31) ASTM D2879-83, Standard Method for Vapor Pressure-Temperature
Relationship and Initial Decomposition Temperature of Liquids by
Isoteniscope, IBR approved for Sec. Sec.  63.111, 63.1402, 63.2406,
63.7944, and 63.12005.
* * * * *

Subpart GGGGG--National Emission Standards for Hazardous Air
Pollutants: Site Remediation

0
3. Section 63.7883 is amended by revising paragraphs (a), (b)
introductory text, (c) introductory text, and (d) introductory text,
and adding paragraph (f) to read as follows:

Sec.  63.7883   When do I have to comply with this subpart?

    (a) If you have an existing affected source, you must comply with
each emission limitation, work practice standard, and operation and
maintenance requirement in this subpart that applies to you no later
than October 9, 2006, except as provided in paragraph (f) of this
section.
    (b) If you have a new affected source that manages remediation
material other than a radioactive mixed waste as defined in Sec.
63.7957, then you must meet the compliance date specified in paragraph
(b)(1) or (2) of this section, as applicable to your affected source,
except as provided in paragraph (f) of this section.
* * * * *
    (c) If you have a new affected source that manages remediation
material that is a radioactive mixed waste as defined in Sec.  63.7957,
then you must meet the compliance date specified in paragraph (c)(1) or
(2) of this section, as applicable to your affected source, except as
provided in paragraph (f) of this section.
* * * * *
    (d) If your facility is an area source that increases its emissions
or its potential to emit such that it becomes a major source of HAP as
defined in Sec.  63.2, then you must meet the compliance dates
specified in paragraphs (d)(1) and (2) of this section, except as
provided in paragraph (f) of this section.
* * * * *
    (f) Sources must comply with the equipment leak requirements of
Sec.  63.7920(b)(3) and (4) and the pressure relief device requirements
of Sec.  63.7920(d) and (e) as specified in paragraphs (f)(1) and (2)
of this section.
    (1) If the affected source's initial startup date is before [DATE
OF PUBLICATION OF THE FINAL RULE IN THE Federal Register], you must
comply with the equipment leak requirements of Sec.  63.7920(b)(3) and
(4) and the pressure relief device requirements of Sec.  63.7920(d) and
(e) of this subpart on or before [DATE ONE YEAR AFTER DATE OF
PUBLICATION OF THE FINAL RULE IN THE Federal Register].
    (2) If the affected source's initial startup date is on or after
[DATE OF PUBLICATION OF THE FINAL RULE IN THE Federal Register], you
must comply with the equipment leak requirements of Sec.  63.7920(b)(3)
and (4) and the pressure relief device requirements of Sec.  63.7920(d)
and (e) of this subpart upon initial startup.
0
4. Section 63.7895 is amended by revising paragraph (c) to read as
follows:

Sec.  63.7895   What emissions limitations and work practice standards
must I meet for tanks?

* * * * *