health and environmentally protective. A brief discussion of the
uncertainties in the RTR emissions datasets, dispersion modeling,
inhalation exposure estimates, and dose-response relationships follows
below. Also included are those uncertainties specific to our acute
screening assessments, multipathway screening assessments, and our
environmental risk screening assessments. A more thorough discussion of
these uncertainties is included in the Automobiles and Light-Duty
Trucks Risk Assessment Report, Miscellaneous Metal Parts and Products
Risk Assessment Report, and Plastic Parts and Products Risk Assessment
Report, available in the respective dockets for this action. If a
multipathway site-specific assessment was performed for any of these
source categories, a full discussion of the uncertainties associated
with that assessment can be found in Appendix 11 of that document,
Site-Specific Human Health Multipathway Residual Risk Assessment
Report.
a. Uncertainties in the RTR Emissions Datasets
    Although the development of the RTR emissions datasets involved
quality assurance/quality control processes, the accuracy of emissions
values will vary depending on the source of the data, the degree to
which data are incomplete or missing, the degree to which assumptions
made to complete the datasets are accurate, errors in emission
estimates, and other factors. The emission estimates considered in this
analysis generally are annual totals for certain years, and they do not
reflect short-term fluctuations during the course of a year or
variations from year to year. The estimates of peak hourly emission
rates for the acute effects screening assessment were based on an
emission adjustment factor applied to the average annual hourly
emission rates, which are intended to account for emission fluctuations
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration
estimates associated with any model, including the EPA's recommended
regulatory dispersion model, AERMOD. In using a model to estimate
ambient pollutant concentrations, the user chooses certain options to
apply. For RTR assessments, we select some model options that have the
potential to overestimate ambient air concentrations (e.g., not
including plume depletion or pollutant transformation). We select other
model options that have the potential to underestimate ambient impacts
(e.g., not including building downwash). Other options that we select
have the potential to either under- or overestimate ambient levels
(e.g., meteorology and receptor locations). On balance, considering the
directional nature of the uncertainties commonly present in ambient
concentrations estimated by dispersion models, the approach we apply in
the RTR assessments should yield unbiased estimates of ambient HAP
concentrations. We also note that the selection of meteorology dataset
location could have an impact on the risk estimates. As we continue to
update and expand our library of meteorological station data used in
our risk assessments, we expect to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant
facilities and emission points, as well as to develop accurate
estimates of the annual emission rates for all relevant HAP, the
uncertainties in our emission inventory likely dominate the
uncertainties in the exposure assessment. Some uncertainties in our
exposure assessment include human mobility, using the centroid of each
census block, assuming lifetime exposure, and assuming only outdoor
exposures. For most of these factors, there is neither an under nor
overestimate when looking at the maximum individual risk or the
incidence, but the shape of the distribution of risks may be affected.
With respect to outdoor exposures, actual exposures may not be as high
if people spend time indoors, especially for very reactive pollutants
or larger particles. For all factors, we reduce uncertainty when
possible. For example, with respect to census-block centroids, we
analyze large blocks using aerial imagery and adjust locations of the
block centroids to better represent the population in the blocks. We
also add additional receptor locations where the population of a block
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from
chronic exposures and noncancer effects from both chronic and acute
exposures. Some

uncertainties are generally expressed quantitatively, and others are
generally expressed in qualitative terms. We note, as a preface to this
discussion, a point on dose-response uncertainty that is stated in the
EPA's 2005 Guidelines for Carcinogen Risk Assessment; namely, that
``the primary goal of EPA actions is protection of human health;
accordingly, as an Agency policy, risk assessment procedures, including
default options that are used in the absence of scientific data to the
contrary, should be health protective'' (the EPA's 2005 Guidelines for
Carcinogen Risk Assessment, page 1-7). This is the approach followed
here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been
developed to generally provide an upper bound estimate of risk.\20\
That is, they represent a ``plausible upper limit to the true value of
a quantity'' (although this is usually not a true statistical
confidence limit). In some circumstances, the true risk could be as low
as zero; however, in other circumstances the risk could be greater.\21\
Chronic noncancer RfC and reference dose (RfD) values represent chronic
exposure levels that are intended to be health-protective levels. To
derive dose-response values that are intended to be ``without
appreciable risk,'' the methodology relies upon an uncertainty factor
(UF) approach,\22\ which considers uncertainty, variability, and gaps
in the available data. The UFs are applied to derive dose-response
values that are intended to protect against appreciable risk of
deleterious effects.
---------------------------------------------------------------------------

    \20\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \21\ An exception to this is the URE for benzene, which is
considered to cover a range of values, each end of which is
considered to be equally plausible, and which is based on maximum
likelihood estimates.
    \22\ See A Review of the Reference Dose and Reference
Concentration Processes, U.S. EPA, December 2002, and Methods for
Derivation of Inhalation Reference Concentrations and Application of
Inhalation Dosimetry, U.S. EPA, 1994.
---------------------------------------------------------------------------

    Many of the UFs used to account for variability and uncertainty in
the development of acute dose-response values are quite similar to
those developed for chronic durations. Additional adjustments are often
applied to account for uncertainty in extrapolation from observations
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all
acute dose-response values are developed for the same purpose, and care
must be taken when interpreting the results of an acute assessment of
human health effects relative to the dose-response value or values
being exceeded. Where relevant to the estimated exposures, the lack of
acute dose-response values at different levels of severity should be
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks
for the environmental risk screening assessment. We established a
hierarchy of preferred benchmark sources to allow selection of
benchmarks for each environmental HAP at each ecological assessment
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but
not all combinations of ecological assessment/environmental HAP had
benchmarks for all three effect levels. Where multiple effect levels
were available for a particular HAP and assessment endpoint, we used
all of the available effect levels to help us determine whether risk
exists and whether the risk could be considered significant and
widespread.
    Although we make every effort to identify appropriate human health
effect dose-response values for all pollutants emitted by the sources
in this risk assessment, some HAP emitted by these source categories
are lacking dose-response assessments. Accordingly, these pollutants
cannot be included in the quantitative risk assessment, which could
result in quantitative estimates understating HAP risk. To help to
alleviate this potential underestimate, where we conclude similarity
with a HAP for which a dose-response value is available, we use that
value as a surrogate for the assessment of the HAP for which no value
is available. To the extent use of surrogates indicates appreciable
risk, we may identify a need to increase priority for an IRIS
assessment for that substance. We additionally note that, generally
speaking, HAP of greatest concern due to environmental exposures and
hazard are those for which dose-response assessments have been
performed, reducing the likelihood of understating risk. Further, HAP
not included in the quantitative assessment are assessed qualitatively
and considered in the risk characterization that informs the risk
management decisions, including consideration of HAP reductions
achieved by various control options.
    For a group of compounds that are unspeciated (e.g., glycol
ethers), we conservatively use the most protective dose-response value
of an individual compound in that group to estimate risk. Similarly,
for an individual compound in a group (e.g., ethylene glycol diethyl
ether) that does not have a specified dose-response value, we also
apply the most protective dose-response value from the other compounds
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are
several factors specific to the acute exposure assessment that the EPA
conducts as part of the risk review under section 112 of the CAA. The
accuracy of an acute inhalation exposure assessment depends on the
simultaneous occurrence of independent factors that may vary greatly,
such as hourly emissions rates, meteorology, and the presence of a
person. In the acute screening assessment that we conduct under the RTR
program, we assume that peak emissions from the source category and
reasonable worst-case air dispersion conditions (i.e., 99th percentile)
co-occur. We then include the additional assumption that a person is
located at this point at the same time. Together, these assumptions
represent a reasonable worst-case actual exposure scenario. In most
cases, it is unlikely that a person would be located at the point of
maximum exposure during the time when peak emissions and reasonable
worst-case air dispersion conditions occur simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening
Assessments
    The ALDT source category emits PB-HAP (lead) and environmental HAP
(lead, HF and HCl); therefore, further evaluation of multipathway risk
and an environmental risk screening was conducted. The MMPP source
category emits PB-HAP (arsenic, cadmium, and lead) and environmental
HAP (arsenic, cadmium, lead, HF, and HCl); therefore, an environmental
risk screening was conducted for this source category. The PPP source
category in this action does not emit any PB-HAP or environmental HAP;
therefore, further evaluation of multipathway risk and an environmental
risk screening was not conducted for this source category.
    For each source category, we generally rely on site-specific levels
of PB-HAP or environmental HAP emissions to determine whether a refined
assessment of the impacts from multipathway exposures is necessary or
whether it is necessary to perform an environmental screening
assessment.

This determination is based on the results of a three-tiered screening
assessment that relies on the outputs from models--TRIM.FaTE and
AERMOD--that estimate environmental pollutant concentrations and human
exposures for five PB-HAP (dioxins, POM, mercury, cadmium, and arsenic)
and two acid gases (HF and HCl). For lead, we use AERMOD to determine
ambient air concentrations, which are then compared to the secondary
NAAQS standard for lead. Two important types of uncertainty associated
with the use of these models in RTR risk assessments and inherent to
any assessment that relies on environmental modeling are model
uncertainty and input uncertainty.\23\
---------------------------------------------------------------------------

    \23\ In the context of this discussion, the term ``uncertainty''
as it pertains to exposure and risk encompasses both variability in
the range of expected inputs and screening results due to existing
spatial, temporal, and other factors, as well as uncertainty in
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents
the actual processes (e.g., movement and accumulation) that might occur
in the environment. For example, does the model adequately describe the
movement of a pollutant through the soil? This type of uncertainty is
difficult to quantify. However, based on feedback received from
previous the EPA SAB reviews and other reviews, we are confident that
the models used in the screening assessments are appropriate and state-
of-the-art for the multipathway and environmental screening risk
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have
been configured and parameterized for the assessment at hand. For Tier
1 of the multipathway and environmental screening assessments, we
configured the models to avoid underestimating exposure and risk. This
was accomplished by selecting upper-end values from nationally
representative datasets for the more influential parameters in the
environmental model, including selection and spatial configuration of
the area of interest, lake location and size, meteorology, surface
water, soil characteristics, and structure of the aquatic food web. We
also assume an ingestion exposure scenario and values for human
exposure factors that represent reasonable maximum exposures.
    For the environmental screening assessment for acid gases, we
employ a single-tiered approach. We use the modeled air concentrations
and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening
assessments, our approach to addressing model input uncertainty is
generally cautious. We choose model inputs from the upper end of the
range of possible values for the influential parameters used in the
models, and we assume that the exposed individual exhibits ingestion
behavior that would lead to a high total exposure. This approach
reduces the likelihood of not identifying high risks for adverse
impacts.
    Despite the uncertainties, when individual pollutants or facilities
do not exceed screening threshold emission rates (i.e., screen out), we
are confident that the potential for adverse multipathway impacts on
human health is very low. On the other hand, when individual pollutants
or facilities do exceed screening threshold emission rates, it does not
mean that impacts are significant, only that we cannot rule out that
possibility and that a refined assessment for the site might be
necessary to obtain a more accurate risk characterization for the
source category.
    The EPA evaluates the following HAP in the multipathway and/or
environmental risk screening assessments, where applicable: Arsenic,
cadmium, dioxins/furans, lead, mercury (both inorganic and methyl
mercury), POM, HCl, and HF. These HAP represent pollutants that can
cause adverse impacts either through direct exposure to HAP in the air
or through exposure to HAP that are deposited from the air onto soils
and surface waters and then through the environment into the food web.
These HAP represent those HAP for which we can conduct a meaningful
multipathway or environmental screening risk assessment. For other HAP
not included in our screening assessments, the model has not been
parameterized such that it can be used for that purpose. In some cases,
depending on the HAP, we may not have appropriate multipathway models
that allow us to predict the concentration of that pollutant. The EPA
acknowledges that other HAP beyond these that we are evaluating may
have the potential to cause adverse effects and, therefore, the EPA may
evaluate other relevant HAP in the future, as modeling science and
resources allow.

IV. Analytical Results and Proposed Decisions

A. What are the analytical results and proposed decisions for the
surface coating of automobiles and light-duty trucks source category?

1. What are the results of the risk assessment and analyses?
    As described in section III of this preamble, for the ALDT source
category, we conducted a risk assessment for all HAP emitted. We
present results of the risk assessment briefly below and in more detail
in the Automobiles and Light-Duty Trucks Risk Assessment Report in the
ALDT Docket (Docket ID No. EPA-HQ-OAR-2019-0314).
a. Chronic Inhalation Risk Assessment Results
    Table 2 of this preamble provides a summary of the results of the
inhalation risk assessment for the source category.

                    Table 2--Surface Coating of Automobiles and Light-Duty Trucks Source Category Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Maximum individual     Estimated population      Estimated annual         Maximum chronic        Maximum screening
                                     cancer risk (in 1     at increased risk of      cancer incidence       noncancer TOSHI \1\   acute noncancer HQ \2\
                                         million)             cancer >=1-in-1        (cases per year)    -----------------------------------------------
                                 ------------------------         million        ------------------------
         Risk assessment                                 ------------------------                          Based on    Based on
                                   Based on    Based on    Based on    Based on    Based on    Based on     actual     allowable      Based on actual
                                    actual     allowable    actual     allowable    actual     allowable   emissions   emissions         emissions
                                   emissions   emissions   emissions   emissions   emissions   emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category.................          10          10      15,000      19,000        0.01        0.01         0.3         0.3  HQREL = 1.
Whole Facility..................          10  ..........      48,000  ..........        0.02  ..........         0.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The target organ specific hazard index (TOSHI) is the sum of the chronic noncancer HQs for substances that affect the same target organ or organ
  system.
\2\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop HQ values.

    The results of the inhalation risk modeling using actual emissions
data, as shown in Table 2 of this preamble, indicate that the maximum
individual cancer risk based on actual emissions (lifetime) could be up
to 10-in-1 million (driven by naphthalene and ethyl benzene from
miscellaneous industrial processes--other/not classified), the maximum
chronic noncancer TOSHI value based on actual emissions could be up to
0.3 (driven by hexamethylene-1,6-diisocyanate from a painting topcoat
process), and the maximum screening acute noncancer HQ value (off-
facility site) could be up to 1 (driven by formaldehyde). The total
estimated annual cancer incidence (national) from these facilities
based on actual emission levels is 0.01 excess cancer cases per year or
1 case in every 100 years.
b. Screening Level Acute Risk Assessment Results
    Table 2 of this preamble shows the acute risk results for the ALDT
source category. The screening analysis for acute impacts was based on
an industry specific multiplier of 1.2, to estimate the peak emission
rates from the average rates. For more detailed acute risk results,
refer to the Automobiles and Light-Duty Trucks Risk Assessment Report,
in the ALDT Docket.
c. Multipathway Risk Screening Results
    The emissions data for the ALDT source category indicate that one
PB-HAP is emitted by sources within this source category: Lead. In
evaluating the potential for multipathway effects from emissions of
lead, we compared modeled annual lead concentrations to the NAAQS for
lead (0.15 [micro]g/m3, arithmetic mean concentration over a 3-month
period). The highest annual average lead concentration of 1.5 x
10-5 [micro]g/m\3\ is below the NAAQS for lead, indicating a
low potential for multipathway impacts of concern due to lead even
assuming a shorter averaging period is. Therefore, we do not expect any
human health multipathway risks as a result of emissions from this
source category.
d. Environmental Risk Screening Results
    The emissions data for the ALDT source category indicate that three
environmental HAP are emitted by sources within this source category:
Lead, HCl and HF. Therefore, we conducted a screening-level evaluation
of the potential adverse environmental effects associated with
emissions of lead, HCl, and HF for the ALDT source category. In
evaluating the potential for adverse environmental effects from
emissions of lead, we compared modeled annual lead concentrations to
the secondary NAAQS for lead (0.15 [micro]g/m\3\, arithmetic mean
concentration over a 3-month period). The highest annual average lead
concentration of 1.5 x 10-5 [micro]g/m\3\ is below the
secondary NAAQS for lead, indicating a low potential for adverse
environmental impacts due to lead even assuming a shorter averaging
period is analyzed. For both HCl and HF, each individual concentration
(i.e., each off-site data point in the modeling domain) was below the
ecological benchmarks for all facilities. Therefore, we do not expect
an adverse environmental effect as a result of HAP emissions from this
source category.
e. Facility-Wide Risk Results
    Fifteen facilities have a facility-wide cancer MIR greater than or
equal to 1-in-1 million. The maximum facility-wide cancer MIR is 10-in-
1 million, driven by naphthalene and ethyl benzene from miscellaneous
industrial processes--other/not classified. The total estimated cancer
incidence from the whole facility is 0.02 excess cancer cases per year,
or one excess case in every 50 years. Approximately 48,000 people were
estimated to have cancer risks above 1-in-1 million from exposure to
HAP emitted from both MACT and non-MACT sources at 15 of the 43
facilities in this source category. The maximum facility-wide TOSHI for
the source category is estimated to be 0.3, mainly driven by emissions
of hexamethylene-1,6-diisocyanate from a painting topcoat process.
f. 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 risks 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 risks from the ALDT source category
across different demographic groups within the populations living near
facilities.\24\
    The results of the demographic analysis are summarized in Table 3
of this preamble. These results, for various demographic groups, are
based on the estimated risks from actual emissions levels for the
population living within 50 km of the facilities.

 Table 3--Surface Coating of Automobiles and Light-Duty Trucks Source Category Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                          Population with
                                                                         cancer risk at or     Population with
                                                                            above 1-in-1      chronic noncancer
                                                          Nationwide       million due to     HI above 1 due to
                                                                         surface coating of  surface coating  of
                                                                          automobiles and      automobiles  and
                                                                         light-duty trucks    light-duty  trucks
----------------------------------------------------------------------------------------------------------------
Total Population......................................     317,746,049               15,000                    0
----------------------------------------------------------------------------------------------------------------
                                          White and Minority by Percent
----------------------------------------------------------------------------------------------------------------
White.................................................              62                   60                    0
Minority..............................................              38                   40                    0
----------------------------------------------------------------------------------------------------------------
                                           Minority Detail by Percent
----------------------------------------------------------------------------------------------------------------
African American......................................              12                   10                    0
Native American.......................................             0.8                  0.2                    0
Hispanic or Latino....................................              18                   27                    0

Other and Multiracial.................................               7                    3                    0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below the Poverty Level...............................              14                   19                    0
Above the Poverty Level...............................              86                   81                    0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 Without High a School Diploma.................              14                   14                    0
Over 25 With a High School Diploma....................              86                   86                    0
----------------------------------------------------------------------------------------------------------------
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated...............................               6                    3                    0
----------------------------------------------------------------------------------------------------------------

    The results of the ALDT source category demographic analysis
indicate that emissions from the source category expose approximately
15,000 people to a cancer risk at or above 1-in-1 million and no one to
a chronic noncancer HI greater than 1. The percent of minorities is
similar nationally (38 percent) and for the category population with
cancer risk greater than or equal to 1-in-1 million (40 percent).
However, the category population with cancer risk greater than or equal
to 1-in-1 million has a greater percentage of Hispanic (27 percent) as
compared to nationally (18 percent).
    The methodology and the results of the demographic analysis are
presented in a technical report titled Risk and Technology Review--
Analysis of Demographic Factors for Populations Living Near Automobile
and Light-Duty Truck Surface Coating Source Category Operations, March
2019 (hereafter referred to as the Automobiles and Light-Duty Trucks
Demographic Analysis Report) in the ALDT Docket.
2. What are our proposed decisions regarding risk acceptability, ample
margin of safety, and adverse environmental effects?
a. Risk Acceptability
    As noted in section III.A of this preamble, 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 risks, the distribution of
cancer and noncancer risks in the exposed population, and risk
estimation uncertainties (54 FR 38044, September 14, 1989).
    For the ALDT source category, the risk analysis indicates that the
cancer risks to the individual most exposed could be up to 10-in-1
million due to actual emissions or based on allowable emissions. These
risks are considerably less than 100-in-1 million, which is the
presumptive upper limit of acceptable risk. The risk analysis also
shows very low cancer incidence (0.01 cases per year for actual and
allowable emissions), and we did not identify a potential for adverse
chronic noncancer health effects. The acute noncancer risks are low at
an HQ of 1 (based on the REL) for formaldehyde. Therefore, we find
there is little potential concern of acute noncancer health impacts
from actual emissions. In addition, the risk assessment indicates no
significant potential for multipathway health effects.
    Considering all of the health risk information and factors
discussed above, including the uncertainties discussed in section
III.C.7 of this preamble, we propose to find that the risks from the
ALDT source category are acceptable.
b. Ample Margin of Safety Analysis
    Although we are proposing that the risks from the ALDT source
category are acceptable, risk estimates for approximately 15,000
individuals in the exposed population are above 1-in-1 million at the
actual emissions level and 19,000 individuals at the allowable
emissions level. Consequently, we further considered whether the MACT
standards for the ALDT source category provide an ample margin of
safety to protect public health. In this ample margin of safety
analysis, we investigated available emissions control options that
might reduce the risk from the source category. We considered this
information along with all of the health risks and other health
information considered in our determination of risk acceptability.
    As described in section III.B of this preamble, our technology
review focused on identifying developments in practices, processes, and
control technologies for the ALDT source category, and the EPA reviewed
various information sources regarding emission sources that are
currently regulated by the ALDT NESHAP. Based on our review, we did not
identify any cost-effective measures to further reduce HAP. Therefore,
considering all of the available health information along with the
absence of additional measures for reducing HAP, we are proposing that
additional emissions controls for this source category are not
necessary and that the current standards provide an ample margin of
safety.
c. Environmental Effects
    The emissions data for the ALDT source category indicate that three
environmental HAP are emitted by sources within this source category:
Lead, HCl, and HF. The screening-level evaluation of the potential for
adverse environmental effects from emissions of lead indicated that the
secondary

NAAQS for lead would not be exceeded by any facility. The screening-
level evaluation of the potential for adverse environmental effects
associated with emissions of HCl and HF from the ALDT source category
indicated that each individual concentration (i.e., each off-site data
point in the modeling domain) was below the ecological benchmarks for
all facilities. In addition, we are unaware of any adverse
environmental effects caused by HAP emitted by this source category.
Therefore, we do not expect there to be 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.
3. 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 ALDT source category. The EPA reviewed
various information sources regarding emission sources that are
currently regulated by the ALDT NESHAP to support the technology
review. The information sources included the following: The RBLC; state
regulations; facility operating permits; regulatory actions, including
technology reviews, promulgated for other surface coating NESHAP
subsequent to the ALDT NESHAP; site visits; discussions with individual
ALDT surface coating facilities; and industry information. The primary
emission sources for the technology review included the following: The
coating operations; all storage containers and mixing vessels in which
coatings, thinners, and cleaning materials are stored or mixed; all
manual and automated equipment and containers used for conveying
coatings, thinners, and cleaning materials; and all storage containers
and all manual and automated equipment and containers used for
conveying waste materials generated by a coating operation.
    Based on our review, we did not identify any add-on control
technologies, process equipment, work practices or procedures that were
not previously considered during development of the 2004 ALDT NESHAP,
and we did not identify any new or improved add-on control technologies
that would result in additional emission reductions. A brief summary of
the EPA's findings in conducting the technology review of ALDT surface
coating operations follows. For a detailed discussion of the EPA's
findings, refer to the memorandum, Technology Review for Surface
Coating Operations in the Automobiles and Light-Duty Trucks Source
Category, in the ALDT Docket.
    During 2004 MACT development for the ALDT NESHAP, numerical
emission limits were determined for new and existing major sources
within the four combinations of coating operations, for a total of
eight HAP emissions limits. The emission limits were based on industry
survey responses and the industry's use of low- or no-HAP coatings and
thinners, high efficiency coatings spray equipment (including robotic
spraying), and add-on capture and control technologies. Alternately,
the NESHAP provides sources with the option of limiting HAP emissions
with capture and add-on control to achieve an overall control
efficiency of 95-percent. During development of that rulemaking, we
identified the beyond-the-floor option to require the use of capture
systems and add-on control devices for all ALDT surface coating
operations. This option was rejected because we determined the
additional emission reductions achieved using the beyond-the-floor
option did not warrant the costs each affected source would incur or
the incremental cost per ton of HAP reduced (67 FR 78622, December 24,
2002).
    For this technology review, we used the EPA's NEI and the ECHO
databases to identify facilities that are currently subject to the ALDT
NESHAP. We also consulted Regional and state regulations and operating
permits. California has existing surface coating rules for VOC from
vehicle assembly plants within two air quality management districts
(AQMD): Bay Area AQMD and South Coast AQMD. No state VOC rules for ALDT
surface coating operations were identified that had VOC limits that
would translate into lower HAP content limits. The VOC content limits
in state rules (e.g., BAAQMD Rule 8-13 and SCAQMD Rule 1115) are an
order of magnitude higher than the HAP content limits in the ALDT
NESHAP. Because the HAP are only a small fraction of the VOC in these
coatings, complying with these state VOC standards would not limit HAP
emissions to levels that are more stringent than the levels required.
    Our search of the RBLC database for improvements in ALDT coating
technologies provided results for 22 facilities with permit dates of
2000 or later. Facilities reported the use of VOC and HAP content
limits, electrodeposition primers, regenerative thermal oxidizers
(RTOs), catalytic oxidation, and thermal oxidation. All of these
control technologies were in use by the ALDT surface coating industry
during development of the ALDT NESHAP and already were considered in
the development of the ALDT NESHAP. Therefore, we concluded that the
results of the search did not result in any improvements in add-on
control technology or other equipment.
    We reviewed other surface coating NESHAP promulgated after the ALDT
NESHAP to determine whether any requirements exceed the ALDT MACT level
of control or included technologies that were not considered during the
development of the original ALDT NESHAP. These NESHAP include Paint
Stripping and Miscellaneous Surface Coating Operations at Area Sources
(40 CFR part 63, subpart HHHHHH), and Nine Metal Fabrication and
Finishing Area Source Categories (40 CFR part 63, subpart XXXXXX). We
also reviewed the results of the technology reviews for the following
NESHAP: Printing and Publishing (40 CFR part 63, subpart KK),
Shipbuilding and Ship Repair (40 CFR part 63, subpart II), Wood
Furniture Manufacturing (40 CFR part 63, subpart JJ), and Aerospace
Manufacturing and Rework Facilities (40 CFR part 63, subpart GG).
    Technology reviews for these NESHAP identified permanent total
enclosures (PTE) and/or RTOs as improvements in add-on control
technology. The original ALDT NESHAP includes a compliance option
involving the use of a PTE and an add-on control device. Because these
measures were considered in the development of the original ALDT NESHAP
and reflected in the MACT level of control, we concluded that these
measures do not represent an improvement in control technology under
CAA section 112(d)(6).
    The control technology assessment conducted for the Paint Stripping
and Miscellaneous Surface Coating NESHAP and Nine Metal Fabrication and
Finishing NESHAP confined all coating operations to a spray booth
fitted with high-efficiency filters, use of high-transfer efficiency
spray guns, and training and certification of spray equipment operator
to optimize transfer efficiency for facilities that spray apply
coatings containing certain inorganic HAP. The technology controls for
inorganic HAP adopted in subparts HHHHHH and XXXXXX, spray booths
fitted with overspray filters and the use of high efficiency spray
equipment, were already considered in the development of the original
ALDT NESHAP, and, therefore, do not

constitute a development for the purpose of the technology review.
    The technology review conducted for the Wood Furniture NESHAP
identified the use of more efficient spray guns as a technology review
development and revised the requirements to prohibit the use of
conventional spray guns. Air-assisted airless spraying was added as a
more efficient coating application technology. The original ALDT NESHAP
is based on the use of high-efficiency application technology, such as
airless and electrostatic spray equipment. This equipment increases
coating transfer efficiency, minimizes emissions by reducing the amount
of coating sprayed and still achieves a given film thickness with
exceptional finish. The format of the ALDT emission limits, in mass of
HAP per mass of coating solids applied to the part, accounts for the
transfer efficiency of the application equipment and is based on high-
efficiency methods.
    The technology review conducted for the Printing and Publishing
NESHAP identified the use of a PTE in the form of coating spray booths
and curing tunnels. These PTEs are commonly used in ALDT surface
coating operations to maintain a clean environment for applying the
coatings, and for capturing and removing coating overspray and solvent
vapors from the coating area. Therefore, the use of a PTE, as
identified in the Printing and Publishing NESHAP technology review,
does not represent a development in control technology with respect to
ALDT surface coating operations.
    In conclusion, we found no improvements in add-on control
technology or other equipment during review of the RBLC, the state
rules, and subsequent NESHAP that were not already identified and
considered during the ALDT NESHAP development.
    Alternatives to conventional solvent-borne coatings were identified
and considered during MACT development but were not considered to be
suitable for all ALDT coating applications. These alternative coatings
include higher solids coatings, waterborne coatings, low-energy
electron beam ultraviolet (UV) cured coatings, and powder coating.
Waterborne and higher solids coatings with lower HAP and VOC content
were considered in the development of the proposed and final standards
and are already reflected in the HAP emission limitations in the final
rule. Industry trends and advances in coating formulation, as
documented in the ACA Industry Market Analysis, showed that powder
coated finishes would be difficult to repair and would likely require
refinishing the entire car in case of damage. Further, the ACA analysis
stated that no progress had been made in overcoming technical hurdles
that would make UV-cured coatings applicable to main vehicle body parts
(e.g., shadowing of certain areas from UV rays, high energy demands,
residual UV photo-initiators in the coating film). Therefore, the EPA
did not identify any developments in coating technology, other process
changes, or pollution prevention alternatives that would represent a
development relative to the coating technologies on which the final
rule is based.
    Finally, no improvements in work practices or operational
procedures were identified for the ALDT source category that were not
previously identified and considered during MACT development. The
current MACT standards require that, if a facility uses add-on controls
to comply with the emission limitations, the facility must develop and
implement a work practice plan to minimize organic HAP emissions from
the storage, mixing, and conveying of coatings, thinners, and cleaning
materials used in, and waste materials generated by, those coating
operations. If a facility is not using add-on controls and is using
either the compliant material option or the emission rate without add-
on controls option, the facility does not need to comply with work
practice standards. Under the emission rate option, HAP emitted from
spills or from containers would be counted against the facility in the
compliance calculations, so facilities must already minimize these
losses to maintain compliance.
    Based on these findings, we conclude that there have not been any
developments in add-on control technology or other equipment not
identified and considered during MACT development, nor any improvements
in add-on controls, nor any significant changes in the cost (including
cost effectiveness) of the add-on controls. Therefore, we are proposing
no revisions to the ALDT NESHAP pursuant to CAA section 112(d)(6). For
further discussion of the technology review results, refer to the
Automobiles and Light-Duty Trucks Technology Review Memo, in the ALDT
Docket.
4. What other actions are we proposing for the ALDT source category?
    We are proposing to require electronic submittal of notifications,
semiannual reports, and compliance reports (which include performance
test reports) for ALDT surface coating facilities. In addition, 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 source owners and operators from the requirement to
comply with otherwise applicable CAA section 112(d) emission standards
during periods of SSM. We are proposing to require periodic emissions
testing of add-on control devices. We also propose other changes,
including updating references to equivalent test methods, making
technical and editorial revisions, and incorporation by reference (IBR)
of alternative test methods. Our analyses and proposed changes related
to these issues are discussed in the sections below.
a. Electronic Reporting Requirements
    The EPA is proposing that owners and operators of ALDT surface
coating facilities submit electronic copies of initial notifications
required in 40 CFR 63.9(b) and 63.3110(b), notifications of compliance
status required in 40 CFR 63.9(h) and 63.3110(c), performance test
reports required in 40 CFR 63.3120(b), and semiannual reports required
in 40 CFR 63.3120(a), through the EPA's Central Data Exchange (CDX)
using the Compliance and Emissions Data Reporting Interface (CEDRI).
For further information regarding the electronic data submission
process, please refer to the memorandum titled Electronic Reporting for
New Source Performance Standards (NSPS) and National Emission Standards
for Hazardous Air Pollutants (NESHAP) Rules, in the ALDT Docket. 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. No specific form is
proposed at this time for the initial notifications required in 40 CFR
63.9(b) and notification of compliance status in 40 CFR 63.9(h). Until
the EPA has completed electronic forms for these notifications, the
notifications will be required to be submitted via CEDRI in PDF. After
development of the final forms, we will notify sources about their
availability via the CEDRI website and the CHIEF Listserv. For
semiannual reports required in 40 CFR 63.3120(a)

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

    \25\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \26\ See Electronic Reporting Template for Surface Coating of
Automobiles and Light-Duty Trucks Subpart IIII Semiannual Reports,
in docket ID NO. EPA-HQ-OAR-0314.
---------------------------------------------------------------------------

    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 63.9(b),
notifications of compliance status required in 40 CFR 63.9(h), and
semiannual reports required in 40 CFR 63.3120(a). 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 CFR
63.3120(g). 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-OAR-2019-0314.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

b. SSM Requirements
(1.) Proposed Elimination of the SSM Exemption
    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 some CAA section 112 standards apply
continuously.
    We are proposing the elimination of the SSM exemption in this rule.
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 2 to subpart IIII of 40 CFR part 63 (Applicability of General
Provisions to Subpart IIII, hereafter referred to as the ``General
Provisions table to subpart IIII''), as explained in more detail below
in section IV.A.4.b.2 of this preamble. For example, we are proposing
to eliminate the incorporation of the General Provisions' requirement
that the source develop an SSM plan. Further, we 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 ensure that the provisions we are proposing to eliminate
are inappropriate, unnecessary, or redundant in the absence of the SSM
exemption. We are specifically seeking comment on whether we have
successfully done so.
    In proposing these rule amendments, the EPA has taken into account
startup and shutdown periods and, for the reasons explained below, has
not proposed alternate standards for those periods. Startups and
shutdowns are part of normal operations for the ALDT source category.
As currently specified in 40 CFR 63.3100(b), all coating operation(s)
must be in compliance with the operating limits for emission capture
systems and add-on control devices required by 40 CFR 63.3093 ``at all
times except during periods of startup, shutdown, and malfunction.''
Therefore, we will be removing the exemption for periods of startup,
and shutdown, as well as for malfunctions. Also, as currently specified
in 40 CFR 63.3100(a), you must be in compliance ``at all times'' with
the emission limitations in 40 CFR 63.3090 and 63.3091, and as
specified in 40 CFR 63.3100(c), you must be in compliance with the work
practice standards in 40 CFR 63.3094 ``at all times.'' During startup
and shutdown periods, in order for a facility (using add-on controls to
meet the standards) to meet the emission and operating standards, the
control device for a coating operation needs to be turned on and
operating at specified levels before the facility begins coating
operations, and the control equipment needs to continue to be operated
until after the facility ceases coating operations. In some cases, the
facility needs to run thermal oxidizers on supplemental fuel before VOC
levels are sufficient for the combustion to be (nearly) self-
sustaining. Note that we are also proposing new related language in 40
CFR 63.3100(d) to require that the owner or operator operate and
maintain the coating operation, including pollution control equipment,
at all times to minimize emissions. See section IV.A.4.b.2 of this
preamble for further discussion of these proposed revisions.
    Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither

predictable nor routine. Instead they are, by definition, sudden,
infrequent and not reasonably preventable failures of emissions
control, process, or monitoring equipment. (40 CFR 63.2) (definition of
malfunction). The EPA interprets CAA section 112 as not requiring
emissions that occur during periods of malfunction to be factored into
development of CAA section 112 standards and this reading has been
upheld as reasonable by the Court in U.S. Sugar Corp. v. EPA, 830 F.3d
579, 606-610 (2016). 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 Agency 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 Agency to consider malfunctions
as part of that analysis. The EPA is not required to treat a
malfunction 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
CAA section 112 standards.
    As the Court recognized in U.S. Sugar Corp, accounting for
malfunctions in setting 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. Id. at 608 (``the
EPA would have to conceive of a standard that could apply equally to
the wide range of possible boiler malfunctions, ranging from an
explosion to minor mechanical defects. Any possible standard is likely
to be hopelessly generic to govern such a wide array of
circumstances.'') 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) (``The 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' ''). 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, emissions during a malfunction event can be significantly
higher than emissions at any other time of source operation. For
example, if an air pollution control device with 99-percent removal
goes off-line as a result of a malfunction (as might happen if, for
example, the bags in a baghouse catch fire) and the emission unit is a
steady state type unit that would take days to shut down, the source
would go from 99-percent control to zero control until the control
device was repaired. The source's emissions during the malfunction
would be 100 times higher than during normal operations. As such, the
emissions over a 4-day malfunction period would exceed the annual
emissions of the source during normal operations. As this example
illustrates, accounting for malfunctions could lead to standards that
are not reflective of (and 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.
    Although no statutory language compels the EPA to set standards for
malfunctions, the EPA has the discretion to do so where feasible. For
example, in the Petroleum Refinery Sector Risk and Technology Review,
the EPA established a work practice standard for unique types of
malfunctions that result in releases from pressure relief devices or
emergency flaring events because we had information to determine that
such work practices reflected the level of control that applies to the
best performing sources (80 FR 75178, 75211-14, December 1, 2015). The
EPA will consider whether circumstances warrant setting standards for a
particular type of malfunction and, if so, whether the EPA has
sufficient information to identify the relevant best performing sources
and establish a standard for such malfunctions. We also encourage
commenters to provide any such information.
    It is unlikely that a malfunction would result in a violation of
the standards during ALDT surface coatings operations for facilities
complying without the use of add-on controls (i.e., using low-HAP
coatings and thinning materials). Facilities using low-HAP coatings and
thinning materials have demonstrated that the coatings and thinners
used in the coating operations are less than or equal to the applicable
emission limit calculated on a monthly basis.
    A malfunction event is more likely for ALDT surface coating
facilities that use add-on controls as a compliance option. For this
option, in addition to demonstrating compliance with the numerical
emission rate limits for coatings and thinners used (calculated on a
monthly basis), facilities must also demonstrate that their emission
capture systems and add-on control devices meet the operating limits
established by the ALDT NESHAP. Control device operating limits are
listed in Table 4 of the ALDT NESHAP and are specific to the device,
and most are based on maintaining an average temperature over a 3-hour
block period, which must not fall below the temperature limit
established during the facility's initial performance test.
    All facilities must also comply with work practice standards to
minimize organic HAP emissions from the storage, mixing, and conveying
of coatings, thinners, and cleaning materials used in, and waste
materials generated by, the coating operation(s), but it is unlikely
that a malfunction would result in a violation of the work practice
standards.
    We currently have no information to suggest that it is feasible or
necessary to establish any type of standard for malfunctions associated
with the ALDT source category. We encourage commenters to provide any
such information, if available.
    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
will 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 will
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).
    If the EPA determines in a particular case that an enforcement
action against a source for violation of an emission standard is
warranted, 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 summary, the EPA interpretation of the CAA and, in particular,
CAA section 112 is reasonable and encourages practices that will avoid
malfunctions. Administrative and judicial procedures for addressing
exceedances of the standards fully recognize that violations may occur
despite good faith efforts to comply and can accommodate those
situations. U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
(2.) Proposed Revisions to the General Provisions Applicability Table
    40 CFR 63.3100(d) General duty. We are proposing to revise the
General Provisions table to subpart IIII (Table 2) entry for 40 CFR
63.6(e)(1)(i) by changing the ``yes'' in column 3 to a ``no.'' 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 63.3100(d) 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 63.3100(d) does not include
that language from 40 CFR 63.6(e)(1)(i).
    We are also proposing to revise the General Provisions table to
subpart IIII (Table 2) entry for 40 CFR 63.6(e)(1)(ii) by changing the
``yes'' in column 3 to a ``no.'' 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 63.3100(d).
    SSM plan. We are proposing to revise the General Provisions table
to subpart IIII (Table 2) entry for 40 CFR 63.6(e)(3) by changing the
``yes'' in column 3 to a ``no.'' Generally, these paragraphs require
development of an SSM plan and specify SSM recordkeeping and reporting
requirements related to the SSM plan. We are also proposing to remove
from 40 CFR part 63, subpart IIII, the current provisions requiring the
SSM plan at 40 CFR 63.3100(f). As 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.
    Compliance with standards. We are proposing to revise the General
Provisions table to subpart IIII (Table 2) entry for 40 CFR 63.6(f)(1)
by changing the ``yes'' in column 3 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 standards apply continuously.
Consistent with Sierra Club, the EPA is proposing to revise the
standards in this rule to apply at all times.
    We are also proposing to remove rule text in 40 CFR 63.3161(j)
clarifying that, in calculating emissions to demonstrate compliance,
deviation periods must include deviations during an SSM period. Since
the EPA is removing the SSM exemption, this clarifying text is no
longer needed.
    40 CFR 63.3163 Performance testing. We are proposing to revise the
General Provisions table to subpart IIII (Table 2) entry for 40 CFR
63.7(e)(1) by changing the ``yes'' in column 3 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
63.3163 and 40 CFR 63.3164. 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 and
language that precluded startup and shutdown periods from being
considered ``representative'' for purposes of performance testing. The
proposed performance testing provisions in 40 CFR 63.3164 will also not
allow performance testing during startup or shutdown. As in 40 CFR
63.7(e)(1), performance tests conducted under this subpart should not
be conducted during malfunctions because conditions during malfunctions
are often not representative of normal operating conditions. Section
63.7(e) requires that the owner or operator maintain records of the
process information necessary to document operating conditions during
the test and include in such records an explanation to support that
such conditions represent normal operation. The EPA is proposing to add
language to 40 CFR 63.3164 clarifying that the owner or operator must
make such records available to the Administrator upon request.
    Monitoring. We are proposing to revise the General Provisions table
to subpart IIII (Table 2) entry for 40 CFR 63.8(c)(1) by changing the
``yes'' in column 3 to a ``no.'' The cross-references to the general
duty and SSM plan requirements in 40 CFR 63.8(c)(1) 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)). Further, we have determined that 40 CFR 63.8(c)(1)(ii) is
redundant to the current monitoring requirement in 40 CFR 63.3168(a)(4)
(i.e., ``have available necessary parts for routine repairs of the
monitoring equipment,'' except 40 CFR 63.8(c)(1)(ii) specifies ``have
readily available.''). We are proposing to revise 40 CFR 63.3168(a)(4)
to specify ``readily available.''
    40 CFR 63.3512 Recordkeeping. We are proposing to revise the
General Provisions table to subpart IIII (Table 2) entry for 40 CFR
63.10(b)(2)(i) by changing the ``yes'' in column 3 to a ``no.'' 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.
    We are proposing to revise the General Provisions table to subpart
IIII (Table 2) entry for 40 CFR 63.10(b)(2)(ii) by changing the ``yes''
in column 3 to a ``no.'' Section 63.10(b)(2)(ii) describes the
recordkeeping requirements during a malfunction, requiring a record of
``the occurrence and duration of each malfunction.'' A similar record
is already required in 40 CFR 63.3130(g), which requires a record of
``the date, time, and duration of each deviation,'' which the EPA is
retaining. The regulatory text in 40 CFR 63.3130(g) differs from the
General Provisions in that the General Provisions requires the creation
and retention of a record of the occurrence and duration of each
malfunction of process, air pollution control, and monitoring
equipment; whereas 40 CFR 63.3130(g) applies 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.'' For
this reason, the EPA is proposing to add to 40 CFR 63.3130(g) a
requirement that sources also keep records that include a list of the
affected source or equipment and actions taken to minimize emissions,
an estimate of the quantity of each regulated pollutant emitted over
the emission limit 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 product-loss calculations, mass
balance calculations, measurements when available, or engineering
judgment based on known process parameters (e.g., coating HAP content
and application rates and control device efficiencies). 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.
    We are proposing to revise the General Provisions table to subpart
IIII (Table 2) entry for 40 CFR 63.10(b)(2)(iv)-(v) by changing the
``yes'' in column 3 to a ``no.'' When applicable, the provision
requires sources to record actions taken during SSM events when actions
were inconsistent with their SSM plan. The requirement in 40 CFR
63.10(b)(2)(iv) 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
63.3130(g)(4). When applicable, the provision in 40 CFR 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.
    We are proposing to revise the General Provisions table to subpart
IIII (Table 2) entry for 40 CFR 63.10(b)(2)(vi) by changing the ``yes''
in column 3 to a ``no.'' The provision requires sources to maintain
records during continuous monitoring system (CMS) malfunctions. Section
63.3130(g) covers records of periods of deviation from the standard,
including instances where a CMS is inoperative or out-of-control.
Additional recordkeeping requirements for continuous parameter
monitoring systems (CPMS) are also specified in 40 CFR 63.3168.
    We are proposing to revise the General Provisions table to subpart
IIII (Table 2) entry for 40 CFR 63.10(c)(15) by changing the ``yes'' in
column 3 to a ``no.'' When applicable, the provision allows an owner or
operator to use the affected source's SSM plan or records kept to
satisfy the recordkeeping requirements of the SSM plan, specified in 40
CFR 63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10)
through (12). The EPA is proposing to eliminate this requirement
because SSM plans would no longer be required, and, therefore, 40 CFR
63.10(c)(15) no longer serves any useful purpose for affected units.
    We are proposing to remove the requirement in 40 CFR 63.3130(g)
that deviation records specify whether deviations from a standard
occurred during a period of SSM. This revision is being proposed due to
the proposed removal of the SSM exemption and because, as discussed
above in this section, we are proposing that deviation records must
specify the cause of each deviation, which could include a malfunction
period as a cause. We are also proposing to remove the requirement to
report the SSM records in 40 CFR 63.6(e)(3)(iii) through (v) by
deleting 40 CFR 63.3130(h).
    40 CFR 63.3120 Reporting. We are proposing to revise the General
Provisions table to subpart IIII (Table 2) entry for 40 CFR 63.10(d)(5)
by changing the ``yes'' in column 3 to a ``no.'' Section 63.10(d)(5)
describes the reporting requirements for startups, shutdowns, and
malfunctions. To replace the General Provisions reporting requirement,
the EPA is proposing to add reporting requirements to 40 CFR
63.3120(a)(5) through (a)(9). 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
compliance report already required under this rule. Subpart IIII of 40
CFR part 63 currently requires reporting of the date, time period, and
cause of each deviation. We are clarifying in the rule that, if the
cause of a deviation from the standard is unknown, this should be
specified in the report. We are also proposing to change ``date and
time period'' to ``date, time, and duration'' (see proposed revisions
to 40 CFR 63.3130(a)(6)(vii), (viii), and (xiii); 40 CFR
63.3130(a)(7)(i); 40 CFR 63.3130(a)(8)(v), (vi), and (vii); and 40 CFR
63.3130(a)(i)) to use terminology consistent with the recordkeeping
section. Further, we are proposing that the report must also contain
the number of deviations from the standard, and a list of the affected
source or equipment. For deviation reports addressing deviations from
an applicable emission limit in 40 CFR 63.3090, 63.3091, or 63.3092, or
an operating limit in Table 1 to 40 CFR part 63, subpart IIII, we are
proposing that the report also include an estimate of the quantity of
each regulated pollutant emitted over any emission limit for which the
source failed to meet the standard, and a description of the method
used to estimate the emissions. For deviation reports addressing
deviations from work practice standards (40 CFR 63.3120(a)(6)(xiii)),
we are retaining the current requirement (including reporting actions
taken to correct the deviation), except that we are revising the rule
language to reference the new general duty requirement in 40 CFR
63.3100(d), we are clarifying that the description of the deviation
must include a list of the affected sources or equipment and the cause
of the deviation, we are clarifying that ``time period'' includes the
``time and duration,'' and we are requiring that the report include the
number of deviations from the work practice standards in the reporting
period.
    Regarding the proposed new requirement discussed above to estimate
the quantity of each regulated pollutant emitted over any emission
limit 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 product-loss calculations, mass balance calculations,
measurements when available, or engineering judgment based on known
process parameters (e.g., coating HAP content and application rates and
control device efficiencies). 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 40 CFR 63.3120(c) that requires reporting of
whether the source deviated from its SSM plan, including required
actions to communicate with the Administrator, and the cross-reference
to 40 CFR 63.10(d)(5)(ii) 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.
    We are proposing to remove the requirements in 40 CFR
63.3120(a)(6)(viii) that deviation reports must specify whether
deviation from an operating limit occurred during a period of SSM. We
are also proposing to remove the requirements in 40 CFR
63.3120(a)(6)(x) to break down the total duration of deviations into
the startup and shutdown categories. As discussed above in this
section, we are proposing to require reporting of the cause of each
deviation. Further, the startup and shutdown categories no longer apply
because these periods are proposed to be considered normal operation,
as discussed in section IV.A.4.b.1 of this preamble.
c. Technical Amendments to the ALDT NESHAP
    We propose to amend 40 CFR 63.3166(b) to add the option of
conducting EPA Method 18 of appendix A-6 to 40 CFR part 60,
``Measurement of Gaseous Organic Compound Emissions by Gas
Chromatography,'' to measure and then subtract methane emissions from
measured total gaseous organic mass emissions as carbon. Facilities
using add-on controls as a compliance option can use either EPA Method
25 or EPA Method 25A to measure control device destruction efficiency.
Unlike EPA Method 25, EPA Method 25A does not exclude methane from the
measurement of organic emissions. Because exhaust streams from coating
operations may contain methane from natural gas combustion, we are
proposing to allow facilities the option to measure methane using EPA
Method 18 and to subtract the methane from the emissions as part of
their compliance calculations.
    We propose to revise the format of references to test methods in 40
CFR part 60. The current reference in 40 CFR 63.3166(a) and (b) to EPA
Methods 1, 1A, 2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 25, and 25A specify
that each method is in ``appendix A'' of part 60. Appendix A of 40 CFR
part 60 has been divided into appendices A-1 through A-8. We propose to
revise each reference to appendix A to indicate which of the eight
sections of appendix A applies to the method.
    We propose to amend 40 CFR 63.3151(a)(1)(i) and (a)(4), and 40 CFR
63.3171(e)(3), which describe how to determine the mass fraction of
organic HAP in each material used, to remove references to Occupational
Safety and Health Administration (OSHA)-defined carcinogens as
specified in 29 CFR 1910.1200(d)(4). The reference to OSHA-defined
carcinogens as specified in 29 CFR 1910.1200(d)(4) is intended to
specify which compounds must be included in calculating total organic
HAP content of a coating material if they are present at 0.1-percent or
greater by mass. We are proposing to remove this reference because 29
CFR 1910.1200(d)(4) has been amended and no longer readily defines
which compounds are carcinogens. We are proposing to replace these
references to OSHA-defined carcinogens and 29 CFR 1910.1200(d)(4) with
a list (in proposed new Table 5 to 40 CFR part 63, subpart IIII) of
those organic HAP that must be included in calculating total organic
HAP content of a coating material if they are present at 0.1-percent or
greater by mass.
    We propose to include organic HAP in proposed Table 5 to 40 CFR
part 63, subpart IIII if they were categorized in the EPA's Prioritized
Chronic Dose-Response Values for Screening Risk Assessments (dated May
9, 2014), as a ``human carcinogen,'' ``probable human carcinogen,'' or
``possible human carcinogen'' according to The Risk Assessment
Guidelines of 1986 (EPA/600/8-87/045, August 1987),\30\ or as
``carcinogenic to humans,'' ``likely to be carcinogenic to humans,'' or
with ``suggestive evidence of carcinogenic potential'' according to the
Guidelines for Carcinogen Risk Assessment (EPA/630/P-03/001F, March
2005).
---------------------------------------------------------------------------

    \30\ See https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
---------------------------------------------------------------------------

    We propose to revise the monitoring provisions for thermal and
catalytic oxidizers to clarify that a thermocouple is part of the gas
temperature monitoring device referred to in 40 CFR 63.3168(c)(3).
    We propose to add a new paragraph 40 CFR 63.3130(p) and to revise
40 CFR 63.3131(a) to allow that any records required to be maintained
by 40 CFR part 63, subpart IIII this part that are submitted
electronically via the EPA's CEDRI may be maintained in electronic
format. We also propose to add clarification that this ability to
maintain electronic copies does not affect the requirement for
facilities to make records, data, and reports available upon request to
a delegated air agency or the EPA as part of an on-site compliance
evaluation.
d. Ongoing Emissions Compliance Demonstrations Requirement
    As part of an ongoing effort to improve compliance with various
federal air emission regulations, the EPA reviewed the compliance
demonstration requirements in the ALDT NESHAP. Currently, if a source
owner or operator chooses to comply with the standards using add-on
controls, the results of an initial performance test are used to
determine compliance; however, the rule does not require on-going
periodic performance testing for these emission capture systems and
add-on controls. We are proposing periodic testing of add-on control
devices, in addition to the one-time initial emissions and capture
efficiency testing and ongoing parametric monitoring to ensure ongoing
compliance with the standards.
    Although ongoing monitoring of operating parameters is required by
the NESHAP, as the control device ages over time, the destruction
efficiency of

the control device can be compromised due to various factors. The EPA
published several documents that identify potential control device
operational problems that could decrease control device efficiency.\31\
These factors are discussed in more detail in the memorandum titled
Proposed Periodic Testing Requirement dated February 1, 2019, included
in the ALDT Docket.
---------------------------------------------------------------------------

    \31\ See Control Techniques for Volatile Organic Compound
Emissions from Stationary Sources, EPA/453/R-92-018, December 1992,
Control Technologies for Emissions from Stationary Sources, EPA/625/
6-91/014, June 1991, and Survey of Control for Low Concentration
Organic Vapor Gas Streams, EPA-456/R-95-003, May 1995. These
documents can be found in the Automobiles and Light-Duty Trucks,
Miscellaneous Metal Parts, and Plastic Parts and Products Dockets
for this action.
---------------------------------------------------------------------------

    The Institute of Clean Air Companies (ICAC), an industry trade
group currently representing 50 emission control device equipment
manufacturers, corroborated the fact that control equipment degrades
over time in their comments on proposed revisions to the NESHAP General
Provisions (72 FR 69, January 3, 2007). ICAC stated that ongoing
maintenance and checks of control devices are necessary in order to
ensure emissions control technology remains effective.\32\ ICAC
identified both thermal and catalytic oxidizers as effective add-on
control devices for VOC reduction and destruction. Thermal oxidizers,
in which ``. . . organic compounds are converted into carbon dioxide
and water . . .'' allow ``. . . for the destruction of VOCs and HAP up
to levels greater than 99-percent . . . '' once ``. . . [t]he oxidation
reaction . . .'' begins, typically ``. . . in the 1,450 degrees
Fahrenheit range.'' That temperature may need to be elevated, depending
on the organic compound to be destroyed. Along with that destruction,
``. . . extreme heat, the corrosive nature of chemical-laden air,
exposure to weather, and the wear and tear of non-stop use . . .''
affect thermal oxidizers such that ``. . . left unchecked, the
corrosive nature of the gases treated will create equipment downtime,
loss of operational efficiency, and eventually failure of the thermal
oxidizer.'' While catalytic oxidizers operate at lower operating
temperatures--typically 440 to 750 degrees Fahrenheit--than thermal
oxidizers, catalytic oxidizers also provide VOC reduction and
destruction. In general, the catalyst ``. . . needs to be checked
periodically to verify the activity of the catalyst . . .'' because
that ``. . . activity or overall ability of the catalyst to convert
target emissions to other by-products will naturally diminish over
time.'' ICAC also mentions chemical poisoning (deactivation of the
catalyst by certain compounds) or masking of the catalyst bed, which
may occur due to changes in manufacturing processes, as means of
catalyst degradation. Finally, ICAC identifies electrical and
mechanical component maintenance as important, for if such components
are not operating properly, ``. . . the combustion temperature in the .
. . oxidizer could drop below the required levels and hazardous air
pollutant (HAP) destruction may not be achieved . . .'' ICAC closes by
noting ``. . . it costs more money to operate an oxidizer at peak
performance, and if not maintained, performance will deteriorate
yielding less destruction of HAP.''
---------------------------------------------------------------------------

    \32\ See Docket Item No. EPA-HQ-OAR-2004-0094-0173, available at
https://www.regulations.gov. A copy of the ICAC's comments on the
proposed revisions to the General Provisions is also included in the
Automobiles and Light-Duty Trucks, Miscellaneous Metal Parts, and
Plastic Parts and Products Dockets for this action.
---------------------------------------------------------------------------

    State websites also provide on-line CAA violations and enforcement
actions which include performance issues associated with control
devices. A recent search resulted in identification of sources in Ohio
and Massachusetts that did not achieve compliance even though they
maintained the thermal oxidizer operating temperatures established
during previous performance tests, which further corroborates with the
ICAC comments and conclusions regarding control device degradation.
    Based on the need for vigilance in maintaining equipment to stem
degradation, we are proposing periodic testing of add-on control
devices once every 5 years, in addition to the one-time initial
emissions and capture efficiency testing and ongoing temperature
measurement to ensure ongoing compliance with the standards.
    In this action, we are proposing to require periodic performance
testing of add-on control devices on a regular frequency (e.g., every 5
years) to ensure the equipment continues to operate properly for
facilities using the emission rate with add-on controls compliance
option. We estimate that 18 ALDT surface coating existing sources are
already required to perform such testing every 5 years synchronized
with 40 CFR part 70 air operating permit renewals and for five
facilities this would be a new requirement. This proposed periodic
testing requirement includes an exception to the general requirement
for periodic testing for facilities using the catalytic oxidizer
control option at 40 CFR 63.3167(b) and following the catalyst
maintenance procedures in 40 CFR 63.3167(b)(6). This exception is due
to the catalyst maintenance procedures that already require annual
testing of the catalyst and other maintenance procedures that provide
ongoing demonstrations that the control system is operating properly
and may, thus, be considered comparable to conducting a performance
test.
    The proposed periodic performance testing requirement allows an
exception from periodic testing for facilities using instruments to
continuously measure emissions. Such continuous emissions monitoring
systems (CEMS) would show actual emissions. The use of CEMS to
demonstrate compliance would obviate the need for periodic oxidizer
testing. Moreover, installation and operation of a CEMS with a
timesharing component, such that values from more than one oxidizer
exhaust could be tabulated in a recurring frequency, could prove less
expensive (estimated to have an annual cost below $15,000) than ongoing
oxidizer testing.
    This proposed requirement does not require periodic testing or CEMS
monitoring of facilities using the compliant materials option or the
emission-rate without add-on controls compliance option because these
two compliance options do not use any add-on controls or control
efficiency measurements in the compliance calculations.
    The proposed periodic performance testing requirement requires
facilities complying with the standards using emission capture systems
and add-on controls and which are not already on a 5-year testing
schedule conduct the first of the periodic performance tests within 3
years of the effective date of the revised standards. Afterward, they
would conduct periodic testing before they renew their operating
permits, but no longer than 5 years following the previous performance
test. Additionally, facilities that have already tested as a condition
of their permit within the last 2 years before the effective date would
be permitted to maintain their current 5-year schedule and not be
required to move up the date of the next test to the 3-year date
specified above. This proposed requirement would require periodic air
emissions testing to measure organic HAP destruction or removal
efficiency at the inlet and outlet of the add-on control device, or
measurement of the control device outlet concentration of organic HAP.
The emissions would be measured as total gaseous organic mass emissions
as carbon using either EPA Method 25 or 25A of appendix A-7 to 40 CFR
part 60, which are the methods currently

required for the initial compliance demonstration.
    We estimate that the cost associated with this proposed
requirement, which includes a control device emissions destruction or
removal efficiency test using EPA Method 25 or 25A, would be
approximately $19,000 per control device. The cost estimate is included
in the memorandum titled Estimated Costs/Impacts 40 CFR Part 63
Subparts IIII, MMMM and PPPP Monitoring Review Revisions, in the ALDT
Docket. We have estimated that five facilities subject to the ALDT
NESHAP and using the add-on control option for compliance are not
currently required to conduct periodic testing as a condition of their
permit renewal. Periodic performance tests ensure that any control
systems used to comply with the NESHAP in the future would be properly
maintained over time, thereby reducing the potential for acute
emissions episodes and non-compliance.
e. IBR of Alternative Test Methods Under 1 CFR Part 51
    The EPA is proposing new and updated test methods for the ALDT
NESHAP that include IBR. In accordance with requirements of 1 CFR 51.5,
the EPA is proposing to incorporate by reference the following
voluntary consensus standards (VCS) into 40 CFR 63.14:
     ASTM Method D1475-13, Standard Test Method for Density of
Liquid Coatings, Inks, and Related Products, proposed to be IBR
approved for 40 CFR 63.3151(b), 63.3941(b) and (c), 63.3951(c),
63.4551(c);
     ASTM D2111-10 (2015), Standard Test Methods for Specific
Gravity of Halogenated Organic Solvents and Their Admixtures, proposed
to be IBR approved for 40 CFR 63.3951(c), 63.4551(c);
     ASTM Method D2369-10 (2015), Test Method for Volatile
Content of Coatings, proposed to be IBR approved for 40 CFR
63.3151(a)(2), 63.3961(j), 63.4541(a), 63.4561(j);
     ASTM Method D2697-03 (2014), Standard Test Method for
Volume Nonvolatile Matter in Clear or Pigmented Coatings, proposed to
be IBR approved for 40 CFR 63.3161(f)(1), 63.3941(b);
     ASTM D5066-91 (Reapproved 2017), Standard Test Method for
Determination of the Transfer Efficiency Under Production Conditions
for Spray Application of Automotive Paints-Weight Basis, proposed to be
IBR approved for 40 CFR 63.3161(g);
     ASTM Method D5965-02 (2013), Standard Test Methods for
Specific Gravity of Coating Powders, proposed to be ICR approved for 40
CFR 63.3151(b), 63.3951(c);
     ASTM Method D6093-97 (2016), Standard Test Method for
Percent Volume Nonvolatile Matter in Clear or Pigmented Coatings Using
Helium Gas Pycnometer, proposed to be IBR approved for 40 CFR
63.3161(f)(1), 63.3941(b);
    ASTM D6266-00a (Reapproved 2017), Test Method for Determining the
Amount of Volatile Organic Compound (VOC) Released from Waterborne
Automotive Coatings and Available for Removal in a VOC Control Device
(Abatement), proposed to be IBR approved for 40 CFR 63.3165(e); and
    EPA-450/3-88-018, Protocol for Determining Daily Volatile Organic
Compound Emission Rate of Automobile and Light-Duty Truck Topcoat
Operations, proposed to be IBR approved for 40 CFR 63.3161(f),
63.3165(e).
    Older versions of ASTM methods D2697, D5965, and D6093 were
incorporated by reference when the ALDT NESHAP was originally
promulgated (69 FR 22602, April 26, 2004). We are proposing to replace
the older versions of these methods and ASTM Method D1475 with updated
versions, which requires IBR revisions. The updated version of the
method replaces the older version in the same paragraph of the rule
text. We are also proposing the addition of ASTM Method D2369 to the
ALDT NESHAP for the first time by incorporating this method by
reference in this rulemaking. Refer to section VIII.J of this preamble
for further discussion of these VCS.
5. What compliance dates are we proposing?
    The EPA is proposing that affected sources must comply with all of
the amendments, with the exception of the proposed electronic format
for submitting semiannual compliance reports, no later than 181 days
after the effective date of the final rule. All affected facilities
would have to continue to meet the current requirements of 40 CFR part
63, subpart IIII until the applicable compliance date of the amended
rule. The final action is not expected to be a ``major rule'' as
defined by 5 U.S.C. 804(2), so the effective date of the final rule
will be the promulgation date as specified in CAA section 112(d)(10).
    For existing sources, we are proposing one change that would impact
ongoing compliance requirements for 40 CFR part 63, subpart IIII. As
discussed elsewhere in this preamble, we are proposing to add a
requirement that notifications, performance test results, and
semiannual compliance reports be submitted electronically. We are
proposing that the semiannual compliance report be submitted
electronically using a new template, which is available for review and
comment as part of this action. We are also proposing to change the
requirements for SSM by removing the exemption from the requirements to
meet the standard during SSM periods and by removing the requirement to
develop and implement an SSM plan. Our experience with similar
industries that are required to convert reporting mechanisms to install
necessary hardware and software, become familiar with the process of
submitting performance test results electronically through the EPA's
CEDRI, test these new electronic submission capabilities, and reliably
employ electronic reporting shows that a time period of a minimum of 90
days, and, more typically, 180 days, is generally necessary to
successfully accomplish these revisions. Our experience with similar
industries further shows that this sort of regulated facility generally
requires a time period of 180 days to read and understand the amended
rule requirements; to evaluate their operations to ensure that they can
meet the standards during periods of startup and shutdown as defined in
the rule and make any necessary adjustments; and to update their
operation, maintenance, and monitoring plan to reflect the revised
requirements. The EPA recognizes the confusion that multiple different
compliance dates for individual requirements would create and the
additional burden such an assortment of dates would impose. From our
assessment of the time frame needed for compliance with the entirety of
the revised requirements, the EPA considers a period of 180 days to be
the most expeditious compliance period practicable and, thus, is
proposing that existing affected sources be in compliance with all of
this regulation's revised requirements within 181 days of the
regulation's effective date.
    We solicit comment on these proposed compliance periods, and we
specifically request submission of information from sources in this
source category regarding specific actions that would need to be
undertaken to comply with the proposed amended requirements and the
time needed to make the adjustments for compliance with any of the
revised requirements. We note that information provided may result in
changes to the proposed compliance dates.

B. What are the analytical results and proposed decisions for the MMPP
source category?

1. What are the results of the risk assessment and analyses?
    As described above in section III of this preamble, for the MMPP
source category, we conducted a risk assessment for all HAP emitted. We
present results of the risk assessment briefly below and in more detail
in the Miscellaneous Metal Parts and Products Risk Assessment Report in
the MMPP Docket (Docket ID No. EPA-HQ-OAR-2019-0312).
a. Chronic Inhalation Risk Assessment Results
    Table 4 below provides a summary of the results of the inhalation
risk assessment for the source category.

                  Table 4--Surface Coating of Miscellaneous Metal Parts and Products Source Category Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Maximum individual     Estimated population      Estimated annual         Maximum chronic        Maximum screening
                                     cancer risk (in 1     at increased risk of      cancer incidence       noncancer TOSHI \1\   acute noncancer HQ \2\
                                         million)             cancer >=1-in-1        (cases per year)    -----------------------------------------------
                                 ------------------------         Million        ------------------------
         Risk assessment                                 ------------------------                          Based on    Based on
                                   Based on    Based on    Based on    Based on    Based on    Based on     actual     allowable      Based on actual
                                    actual     allowable    actual     allowable    actual     allowable   emissions   emissions         emissions
                                   emissions   emissions   emissions   emissions   emissions   emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source category.................          20          30      18,000      24,000       0.008        0.01         0.8           1  HQREL = 4
Whole facility..................         100  ..........     370,000  ..........        0.04  ..........           1  ..........  ......................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The TOSHI is the sum of the chronic noncancer HQ for substances that affect the same target organ or organ system.
\2\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop HQ values.

    The results of the inhalation risk modeling using actual emissions
data, as shown in Table 4 above, indicate that the maximum individual
cancer risk based on actual emissions (lifetime) could be up to 20-in-1
million (driven by naphthalene and ethyl benzene from coating
operations), the maximum chronic noncancer TOSHI value based on actual
emissions could be up to 0.8 (driven by antimony from coating
operations), and the maximum screening acute noncancer HQ value (off-
facility site) could be up to 4 (driven by glycol ethers). The total
estimated annual cancer incidence (national) from these facilities
based on actual emission levels is 0.008 excess cancer cases per year
or 1 case in every 125 years.
b. Screening Level Acute Risk Assessment Results
    Table 4 of this preamble also shows the acute risk results for the
MMPP source category. The screening analysis for acute impacts was
based on an industry-specific multiplier of 1.2, to estimate the peak
emission rates from the average emission rates. For more detailed acute
risk results refer to the Miscellaneous Metal Parts and Products Risk
Assessment Report, in the MMPP Docket.
c. Multipathway Risk Screening Results
    The emissions data for the MMPP source category indicate that three
PB-HAP are emitted by sources within this source category: Arsenic,
cadmium, and lead. Of the 368 facilities in the source category, two
facilities reported emissions of carcinogenic PB-HAP (arsenic) and two
facilities reported emissions of non-carcinogenic PB-HAP (cadmium). The
PB-HAP emissions from these facilities did not exceed the Tier 1
multipathway screening value of 1 for cancer or noncancer.
    In evaluating the potential for multipathway effects from emissions
of lead, we compared modeled annual lead concentrations to the NAAQS
for lead (0.15 [micro]g/m\3\, arithmetic mean concentration over a 3-
month period). The highest annual average lead concentration of 0.059
[micro]g/m\3\ is below the NAAQS level for lead, indicating a low
potential for multipathway impacts of concern due to lead even assuming
a shorter averaging period is analyzed.
d. Environmental Risk Screening Results
    The emissions data for the MMPP source category indicate that four
environmental HAP are emitted by sources within this source category:
Arsenic, cadmium, lead and HCl. Therefore, we conducted a screening-
level evaluation of the potential adverse environmental effects
associated with emissions of arsenic, cadmium, lead, and HCl for the
MMPP source category. In the Tier 1 screening analysis for PB-HAP
(other than lead which was evaluated differently), arsenic and cadmium
had no exceedances of any of the ecological benchmarks evaluated.
    In evaluating the potential for adverse environmental effects from
emissions of lead, we compared modeled annual lead concentrations to
the secondary NAAQS for lead (0.15 [micro]g/m\3\, arithmetic mean
concentration over a 3-month period). The highest annual average lead
concentration of 0.059 [micro]g/m\3\ is below the secondary NAAQS for
lead, indicating a low potential for adverse environmental impacts due
to lead even assuming a shorter averaging period is analyzed. For HCl,
each individual concentration (i.e., each off-site data point in the
modeling domain) was below the ecological benchmarks for all
facilities. Therefore, we do not expect an adverse environmental effect
as a result of HAP emissions from this source category.
e. Facility-Wide Risk Results
    One hundred and one facilities have a facility-wide cancer MIR
greater than or equal to 1-in-1 million. The maximum facility-wide
cancer MIR is 100-in-1 million, driven by nickel emissions from
welding. The total estimated cancer incidence from the whole facility
is 0.01 excess cancer cases per year, or one excess case in every 100
years. Approximately 370,000 people were estimated to have cancer risks
above 1-in-1 million from exposure to HAP emitted from both MACT and
non-MACT sources of the 368 facilities in this source category. The
maximum facility-wide TOSHI for the source category is estimated to be
1, driven by emissions of cobalt from a gel coating operation.
f. 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 risks 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 risks from the MMPP source category
across different demographic groups

within the populations living near facilities.
    The results of the demographic analysis are summarized in Table 5
of this preamble. These results, for various demographic groups, are
based on the estimated risks from actual emissions levels for the
population living within 50 km of the facilities.

  Table 5--Surface Coating of Miscellaneous Metal Parts and Products Source Category Demographic Risk Analysis
                                                     Results
----------------------------------------------------------------------------------------------------------------
                                                                          Population with
                                                                         cancer risk at or     Population with
                                                                            above 1-in-1      chronic noncancer
                                                        Nationwide         million due to     HI above 1 due to
                                                                         surface coating of   surface coating of
                                                                        miscellaneous metal  miscellaneous metal
                                                                         parts and products   parts and products
----------------------------------------------------------------------------------------------------------------
Total Population.................................          317,746,049               18,000                    0
----------------------------------------------------------------------------------------------------------------
                                          White and Minority by Percent
----------------------------------------------------------------------------------------------------------------
White............................................                   62                   75                    0
Minority.........................................                   38                   25                    0
----------------------------------------------------------------------------------------------------------------
                                           Minority Detail by Percent
----------------------------------------------------------------------------------------------------------------
African American.................................                   12                   12                    0
Native American..................................                  0.8                  0.6                    0
Hispanic or Latino...............................                   18                    9                    0
Other and Multiracial............................                    7                    3                    0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below the Poverty Level..........................                   14                   20                    0
Above the Poverty Level..........................                   86                   80                    0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 Without High a School Diploma............                   14                   18                    0
Over 25 With a High School Diploma...............                   86                   82                    0
----------------------------------------------------------------------------------------------------------------
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated..........................                    6                    3                    0
----------------------------------------------------------------------------------------------------------------

    The results of the MMPP source category demographic analysis
indicate that emissions from the source category expose approximately
18,000 people to a cancer risk at or above 1-in-1 million and no one is
exposed to a chronic noncancer HI greater than 1. The percentages of
the at-risk population in the following specific demographic groups are
higher than their respective nationwide percentages: ``White,'' ``Below
the Poverty Level,'' and ``Over 25 and without a high school diploma.''
    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 Surface Coating of
Miscellaneous Metal Parts and Products Source Category, May 2019
(hereafter referred to as the Miscellaneous Metal Parts and Products
Demographic Analysis Report), available in the MMPP Docket.
2. What are our proposed decisions regarding risk acceptability, ample
margin of safety, and adverse environmental effects?
a. Risk Acceptability
    As noted in section III.A of this preamble, 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 risks, the distribution of
cancer and noncancer risks in the exposed population, and risk
estimation uncertainties (54 FR 38044, September 14, 1989).
    For the MMPP source category, the risk analysis indicates that the
cancer risks to the individual most exposed could be up to 20-in-1
million due to actual emissions and up to 30-in-1 million due to
allowable emissions. These risks are considerably less than 100-in-1
million, which is the presumptive upper limit of acceptable risk. The
risk analysis also shows very low cancer incidence (0.008 cases per
year for actual emissions and 0.01 cases per year for allowable
emissions), and we did not identify potential for adverse chronic
noncancer health effects.
    The acute screening analysis results in a maximum acute noncancer
HQ of 4 at one facility based on use of the acute REL for ethylene
glycol monomethyl ether as a surrogate for unspeciated glycol ethers.
Since there is not a specified acute dose-response value for
unspeciated glycol ethers, we applied the most protective dose-response
value from the other glycol ether compounds, the acute REL for ethylene
glycol monomethyl ether, to estimate risk. Given that ethylene glycol
monomethyl ether is more toxic than other glycol ethers, the use of
this surrogate is a health-protective choice in the EPA's risk
assessment.
    For acute screening analyses, to better characterize the potential
health risks

associated with estimated worst-case acute exposures to HAP, we examine
a wider range of available acute health metrics than we do for our
chronic risk assessments. This is in acknowledgement that there are
generally more data gaps and uncertainties in acute reference values
than there are in chronic reference values. By definition, the acute
REL represents a health-protective level of exposure, with effects not
anticipated below those levels, even for repeated exposures; however,
the level of exposure that would cause health effects is not
specifically known. As the exposure concentration increases above the
acute REL, the potential for effects increases. Therefore, when an REL
is exceeded and an AEGL-1 or ERPG-1 level is available (i.e., levels at
which mild, reversible effects are anticipated in the general
population for a single exposure), we typically use them as an
additional comparative measure, as they provide an upper bound for
exposure levels above which exposed individuals could experience
effects. However, for glycol ethers, there are no AEGL or ERPG values.
    Additional uncertainties in the acute exposure assessment that the
EPA conducts as part of the risk review under section 112 of the CAA
include several factors. The accuracy of an acute inhalation exposure
assessment depends on the simultaneous occurrence of independent
factors that may vary greatly, such as hourly emission rates,
meteorology, and the presence of a person. In the acute screening
assessment that we conduct under the RTR program, we include the
conservative (health-protective) assumptions that peak emissions from
each emission point in the source category and reasonable worst-case
air dispersion conditions (i.e., 99th percentile) co-occur. We then
include the additional assumption that a person is located at this
point at the same time. Together, these assumptions represent a
reasonable exposure. In most cases, it is unlikely that a person would
be located at the point of maximum exposure during the time when peak
emissions and reasonable worst-case air dispersion conditions occur
simultaneously. Thus, as discussed in the document titled Residual Risk
Assessment for the Surface Coating of Miscellaneous Metal Parts and
Products Source Category in Support of the Risk and Technology Review
2019 Proposed Rule, in the docket for this action, by assuming the co-
occurrence of independent factors for the acute screening assessment,
the results are intentionally biased high and are, thus, health-
protective. We conclude that adverse effects from acute exposure to
emissions of glycol ethers from this source category are not
anticipated.
    Considering all of the health risk information and factors
discussed above, including the uncertainties discussed in section
III.C.7 of this preamble, we propose that the risks from the MMPP
source category are acceptable.
b. Ample Margin of Safety Analysis
    Although we are proposing that the risks from the MMPP source
category are acceptable, risk estimates for approximately 18,000
individuals in the exposed population are above 1-in-1 million at the
actual emissions level and 24,000 individuals in the exposed population
are above 1-in-1 million at the allowable emissions level.
Consequently, we further considered whether the MACT standards for the
MMPP source category provide an ample margin of safety to protect
public health. In this ample margin of safety analysis, we investigated
available emissions control options that might reduce the risk from the
source category. We considered this information along with all of the
health risks and other health information considered in our
determination of risk acceptability.
    As described in section III.B of this preamble, our technology
review focused on identifying developments in practices, processes, and
control technologies for the MMPP source category, and we reviewed
various information sources regarding emission sources that are
currently regulated by the MMPP NESHAP.
    Based on our review (described in section IV.B.3 of this preamble),
we identified and evaluated the use of add-on control technologies for
the rubber-to-metal bonding and high- performance subcategories.
    For the rubber-to-metal bonding subcategory, we evaluated the
option of lowering the existing source limit to an emission limit of 10
lb HAP/gallon (gal) solids. Two facilities may need to install thermal
oxidizers, if alternative low-HAP coatings or other compliance options
are not available. The thermal oxidizers would require a total capital
investment of $2 million (combined) for the two facilities, and total
annual costs of $410,000 (combined). Estimated emission reductions from
the two facilities would be 43 tpy of HAP, and the estimated cost
effectiveness would $9,500 per ton of HAP reduced.
    For the high-performance subcategory, we evaluated lowering both
the existing and new source limits to the general use subcategory
existing source limit of 2.6 lb HAP/gal solids. One facility in the
high-performance coating subcategory may need to install a thermal
oxidizer if alternative low-HAP coatings or other compliance options
are not available. The cost of installing a thermal oxidizer at this
one facility would require a total capital investment of $2.3 million,
and total annual costs of $620,000. The estimated emission reduction at
this one facility would be 53 tpy of HAP, and the estimated cost
effectiveness would be $11,700 per ton of HAP reduced.
    We have determined that the added costs and cost effectiveness for
these two coating subcategories ($9,500 per ton of HAP reduced for the
rubber-to-metal coating subcategory and $11,700 per ton for the high
performance subcategory) are not justified. We think these costs are
unreasonable particularly because the risks are already low, and the
risks would not be reduced in a meaningful manner by the control of
these subcategories. We are proposing that additional emissions
controls for this source category are not necessary to provide an ample
margin of safety.
c. Environmental Effects
    The emissions data for the MMPP source category indicate that four
environmental HAP are emitted by sources within this source category:
Arsenic, cadmium, lead, and HCl. In the Tier 1 screening analysis for
PB-HAP (other than lead which was evaluated differently), arsenic and
cadmium had no exceedances of any of the ecological benchmarks
evaluated. For lead, we did not estimate any exceedances of the
secondary lead NAAQS. The screening-level evaluation of the potential
for adverse environmental effects associated with emissions of HCl from
the MMPP source category indicated that each individual concentration
(i.e., each off-site data point in the modeling domain) was below the
ecological benchmarks for all facilities. In addition, we are unaware
of any adverse environmental effects caused by HAP emitted by this
source category.
    Therefore, we do not expect there to be 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.

3. 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 MMPP source category. The EPA reviewed
various information sources regarding emission sources that are
currently regulated by the MMPP NESHAP to support the technology
review. The information sources include the following: The RBLC;
publicly available state air permit databases and facility operating
permits compliance reports; regulatory actions, including technology
reviews promulgated for other surface coating NESHAP subsequent to the
promulgation of the MMPP NESHAP; state regulations; site visits; and
industry information.
    Based on our review, we identified and evaluated the use of add-on
control technologies for two coating subcategories that had not been
previously considered during development of the MMPP NESHAP. This
analysis is described in detail in the following paragraphs. Aside from
this, we did not identify any new or improved process equipment, work
practices, or procedures that would further reduce emissions. For a
detailed discussion of the EPA's findings, refer to the Miscellaneous
Metal Parts and Products Technology Review Memo, in the MMPP Docket.
    During the development of the 2004 MMPP NESHAP, numerical emission
limits were determined for new and existing major sources within five
coating subcategories for a total of 10 HAP emissions limits. The MACT
emission limits were based on different data sources, depending on the
coating subcategory. In the general use coating subcategory and the
high- performance coating subcategory, the MACT emission limits were
based on the most stringent state VOC limits and HAP-to-VOC ratios to
convert the VOC limits to HAP limits. For the general use coating
subcategory, the HAP-to-VOC ratio was developed from industry survey
data. For the high-performance coating subcategory, the HAP-to-VOC
ratio was developed from industry information. For rubber-to-metal
coating, the MACT emission limits were based on survey data on the HAP
content of the coatings. For magnet wire coating, the MACT emission
limits were based on survey data and also accounted for the fact that
magnet wire coating uses an oven to cure the coatings that is fueled by
coating solvent vapors, reducing overall emissions. For the EPFP
coating subcategory, the MACT emission limits were based on data
received in public comments on the proposed NESHAP.
    With the exception of the emission limits for the magnet wire
coating subcategory, none of the emission limits for new or existing
sources in the other subcategories accounted for the use of add-on
controls, and the documentation of the MACT analysis did not identify
facilities that were using add-on controls.
    The EPA investigated the use of emissions capture systems and add-
on controls but found that the costs would be prohibitive for the
incremental emissions reductions achieved. The EPA estimated that it
would be technically feasible for capture systems and add-on controls
could reduce emissions by at least 95 percent, but the cost for
facilities in this source category could be as much as $1 million. The