1 A. What are the results and proposed decisions for the Chromium Electroplating source categories ? 1. Overview of the source categories and MACT Standard.

National Emission Standards for Chromium Emissions from Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks (Chromium Electroplating MACT standards) were promulgated on January 25, 1995 (60 FR 4963) and codified at 40 CFR part 63, subpart N. The Chromium Electroplating MACT standards regulate emissions of chromium compounds from three related source categories: hard chromium electroplating, decorative chromium electroplating, and chromium anodizing. Within these source categories, the MACT standards apply to all plants, both major and area sources, regardless of size. The Hard Chromium Electroplating source category consists of facilities that plate base metals with a relatively thick layer of chromium using an electrolytic process. Hard chromium electroplating provides a finish that is resistant to wear, abrasion, heat, and corrosion. These facilities plate large cylinders and industrial rolls used in construction equipment and printing presses, hydraulic cylinders and rods, zinc die castings, plastic molds, engine components, and marine hardware. The Decorative Chromium Electroplating source category consists of facilities that plate base materials such as brass, steel, aluminum, or plastic with layers of copper and nickel,2 followed by a relatively thin layer of chromium to provide a bright, tarnish- and wear-resistant surface. Decorative chromium electroplating is used for items such as automotive trim, metal furniture, bicycles, hand tools, and plumbing

fixtures. The Chromium Anodizing source category consists of facilities that use chromic acid to form an oxide layer on aluminum to provide resistance to corrosion. The chromium anodizing process is used to coat aircraft parts (such as wings and landing gears) as well as architectural structures that are subject to high stress and corrosive conditions. The HAP emission sources subject to the Chromium Electroplating NESHAP are the tanks in which the chromium deposition takes place. For hard chromium and decorative chromium electroplating facilities, the emission sources are electroplating tanks. For the Chromium Anodizing source category, the emission sources are anodizing tanks. The primary emission controls used by the facilities in these source categories include packed bed scrubbers, mesh pad mist eliminators, composite mesh pad (CMP) systems, high efficiency particulate air (HEPA) filters, and wetting agent/fume suppressants (WAFS). Most decorative chromium electroplating plants comply with the MACT standards by using WAFS in the tank bath to control surface tension, which in turn3 reduces emissions. Some plants use a combination of WAFS and add-on control to meet the MACT emission limits. If a facility controls emissions using an add-on control device, the tank is generally equipped with a hood and duct work to exhaust emissions through the control device and out the stack. However, when WAFS are used as the only means of emission control, the tanks often are not equipped with exhaust hoods. In such cases, emissions from the tank are fugitive and are exhausted to the outside using wall-mounted exhaust fans. We estimate that there are approximately 1,770 plants that are currently subject to the Chromium Electroplating MACT standards. Of these, we estimate that there are 790 hard chromium electroplating plants, 740 decorative chromium electroplating plants, and 240 chromium anodizing plants. A detailed description of how the number of each type of plant was estimated can be found in the “Cr Electroplating Estimated

Number of Plants" document available in the docket for this action. Some facilities perform more than one type of chromium electroplating or anodizing. For purposes of our estimates, we classified facilities as hard chromium, decorative chromium, or chromium anodizing based on the primary type of electroplating operation performed at the facility. Some chromium electroplating facilities electroplate items that are used internally in the manufacturing process at the same facility or4 within the same company. For example, some large printing facilities electroplate their printing rollers in house, and the chromium electroplating processes are located at the same site as the printing and publishing processes. 2. What data were used in our risk analyses? For the chromium electroplating source categories, we compiled a preliminary data set using data in the 2005 NEI. A

review of the NEI resulted in the identification of data for 122 chromium electroplating facilities. These data were reviewed and the data for eight hard chromium and six decorative chromium electroplating plants were revised based on information in the facilities’ permits or permit applications. Additional data were available for 44 facilities through responses to a CAA section 114 information request that was sent to facilities for the Plating and Polishing Area Source rule. The data for these facilities were added to the NEI data set and, as with the original data, represent actual emission levels for these chromium electroplating facilities. Most of these facilities have low emissions, which are generally less than 2 pounds per year. These 166 facilities now included in the NEI comprise approximately 9 percent of the estimated 1,770 facilities covered by the MACT standards and include 63 hard chromium electroplating, 96 decorative chromium electroplating, and 7 chromium anodizing facilities. This data set of 166 facilities5 were modeled to determine the maximum individual cancer risk, the population cancer risk, the cancer incidence, and the maximum chronic non-cancer risk for the three source categories

based on actual emissions. The maximum individual cancer risk

and the maximum chronic non-cancer risk estimated from this data set were also compared to the maximum individual cancer risk and

the maximum chronic non-cancer risk estimated from MACTallowable emissions for the three source categories. To address the possibility that the small number of facilities included in the 166-facility data set might not be fully representative of the source categories and their risks, we developed an additional data set. In the development of this data set we used “model plants” developed for the original MACT standard to represent the individual facilities. For hard and decorative chromium electroplating we used three model plants (large, medium, and small) that represent average characteristics for each of these groups. For each of these plant sizes, there is an annual emissions rate (lbs/yr) that is derived from the design and operating parameters and is specific to the size and type of model plant. For chromium anodizing we have two model plants (large and small). The model plants were based on data collected during development of the original MACT

standards from 1988 to 1993 from more than 100 facilities that responded to an information collection request for the chromium6 electroplating and anodizing industry. Data from site visits and other information also were used in developing the model plants. A complete description of the model plants developed for the MACT standard is provided in the Background Information Document for the original MACT standard (Chromium Electroplating BID). The basis for this additional data set is 1,629 chromium electroplating facilities with known addresses. 1 For about half of these facilities the type of electroplating performed is known but the size of the facility is not known. For the remaining facilities neither the type of chromium electroplating process or processes nor the facility size is known. For use in the risk analysis, the limited available data were used to divide these facilities into six groups. Facilities in three of the six groups were assigned to be hard chromium electroplating facilities. Those groups include: hard chromium facilities; facilities with combined hard chromium operations and other electroplating or anodizing; and facilities with unknown processes. Together, these three groups yielded a total of 1,219 plants, all of which we modeled as hard chromium electroplating facilities. The 1,219 model plants included in this data set is substantially higher than the 790 hard chromium

1 There is some overlap between the 1,629 facilities with known addresses and the 166 facilities for which we have emissions data based on the NEI and the data collection request.7 facilities that we estimate exist in the United States. However, because hard chromium facilities have the highest emissions among the three source categories, we made these selections as a conservative or health-protective assumption. The purpose of the residual risk standards under section 112(f) is to ensure protection of public health and the environment. Thus, we believe it is important to develop a conservative risk analysis and err on the side of potential overestimation of risk analyses where we are missing data. To represent the decorative chromium electroplating facilities, we combined two of the six groups of facilities; decorative chromium facilities and facilities that perform both decorative chromium and chromium anodizing. This results in 319 decorative chromium facilities in this data set, which even when combined with the 96 decorative chromium electroplating facilities in the NEI data set, is less than the 740 facilities that we believe exist in the industry. Because we modeled allof the unknown electroplating type facilities as the highestemitting hard chromium electroplating facilities, we consider this assessment to be conservative even though it appears to under-represent decorative chromium facilities. Similarly, the last of the six groups are all known chromium anodizing facilities. This group includes 73 facilities, and when combined with the 7 chromium anodizing8 facilities in the NEI data set, still represents only about a third of the 240 facilities chromium anodizing facilities. Again, we believe this is conservative because those facilities not modeled as chromium anodizing plants were modeled as the higher emitting hard chromium facilities in the analysis. To estimate the risks for this assessment, we needed to establish estimated emissions for each of the electroplating and anodizing types. To ensure that we did not underestimate cancer risk to the most exposed individual, we originally planned to use the large plant emission factors that we had developed for the original MACT standard to represent all model plants for each type of chromium electroplating processing. In reviewing available emissions data, we found that while the large plant emission factors adequately represent the average chromium emissions from known large decorative chromium electroplating and large chromium anodizing facilities, they are not representative of the average chromium emissions from large hard chromium electroplating facilities. The emission factor for large hard chromium electroplating developed as part of the model plant analysis for the original MACT standard was 35.3 pounds per year (lbs/yr). However, in comparing this emission factor to available emissions data for

individual facilities we find that this emissions factor is unrealistically high and does not represent the average level of9 emissions for large facilities as we would expect to see under the current MACT standard. As explained more fully in the

"Model Plant Data Used to Estimate Risk from Chromium Electroplating Sources" document available in the docket for this action, based on the large model plant design flow rate and operating hours, a large hard chromium model plant operating at the MACT emission limit of 0.015 milligrams per dry standard cubic meter (mg/dscm) would emit a maximum of only 23.6 lbs/yr of chromium compounds. Moreover, the available data on actual emissions for hard chromium electroplating plants indicate there are only 4 plants with annual emissions greater than 10 lbs/yr. As a result, we determined that the large size model plant emissions factor, as defined for the original MACT standard, is not representative of existing large hard chromium electroplating facilities on a nationwide basis. However, the

emission factor associated with a medium size hard chromium electroplating model plant (9.26 lbs/yr) falls between the 90th percentile (8.04 lbs/yr) and the 95th percentile (11.6 lbs/yr) of the available emissions data for hard chromium electroplating facilities. Because this emission factor is representative of the emissions from large facilities, the emissions factor of 9.26 lbs/yr was used to represent current large hard chromium electroplating facilities. Thus, for purposes of this residual1 0 risk review, we refer to 9.26 lbs/yr as the emissions factor for a "large" hard chromium electroplating facility. We believe the approach of using the “large” facility emissions factor to represent all facility sizes is reasonable

to ensure that we did not underestimate maximum individual cancer risk. Although we believe that only a small percentage of the facilities are large, we recognize that we do not have emissions data for approximately 90% of the sources. Thus, by assuming all sources are large, we have ensured that we will not

underestimate the maximum individual risk. For hard chromium electroplating, the model plant emission factors for small, medium, and large facilities range from 0.55 to 9.26 lbs/yr. While we expect only 10 percent of the facilities to be large, based on the distribution of model plant sizes developed for the MACT standard, we used the emissions factor for a large facility (9.26 lbs/yr) for all of the 1,219 facilities that we considered as hard chromium electroplating facilities. Similarly, for decorative chromium electroplating, the emission factors for small, medium, and large facilities are 0.065, 0.27, and 2.65 lbs/yr, respectively, and the large facility emissions factor was used in the risk assessment for decorative chromium. For the decorative chromium category, we estimate that only five percent of the facilities are large, based upon the distribution of decorative chromium plants1 1 nationwide when the original NESHAP was developed. Finally, for chromium anodizing, the emission factor for small facilities is 0.036 lbs/yr and for large facilities is 0.44 lbs/yr. The large facility emissions factor (0.44 lbs/yr) was used in the conservative analysis for all of the anodizing facilities even though we estimate that only 25 percent are large. Population risk indicators can be greatly overstated when highly conservative emission estimates are applied to every facility in the source category. Recognizing this fact, we performed a supplemental analysis to assess the sensitivity of our population risk estimates. Thus, as described further below, the supplemental analysis was performed to understand the degree to which the risk might be overstated and thus how much weight to attach to the conservative analysis, The conservatism

of this risk assessment is one factor that we consider in determining whether the risk is acceptable within the meaning of

the benzene NESHAP. For the supplemental analysis, we assigned unique emission factors to each of the 6 groups of facilities in our 1,629 facility data set. These emission factors were developed to better estimate the average emissions for all of the sources within each group. The new emission factors are:

• 2.24 lbs/yr for known hard chromium electroplating facilities,1 2 • 0.225 lbs/yr for known decorative chromium electroplating facilities,

• 0.137 lbs/yr for known chromium anodizing facilities,

• 1.23 lbs/yr for facilities with combinations of hard chromium electroplating and either decorative electroplating or anodizing,

• 0.181 lbs/yr for facilities with combinations of decorative electroplating and anodizing, and

• 1.11 lbs/yr for facilities where the type of process (electroplating or anodizing) is unknown. A detailed explanation for how these emission factors were

derived can be found in the "Model Plant Data Used to Estimate Risk from Chromium Electroplating Sources" available in the docket for this action. These weighted average emission factors account for the plant type (hard chromium electroplating, decorative chromium electroplating, or chromium anodizing) and the distribution of plant sizes (large, medium, or small). For example, the average emissions factor for hard chromium electroplating (2.24 lbs/yr) is the weighted average of the model plant emission factors for large plants (10 percent of plants at 9.26 lbs/yr per plant); medium plants (20 percent of plants at 4.63 lbs/yr per plant, and small plants (70 percent of plants at 0.55 lbs/yr per plant). This distribution of plant1 3 sizes is based on actual data collected during development of the original MACT rule. We have no reason to believe the distribution of facility sizes has changed significantly since

then.

The uncertainties associated with both the conservative analysis and the supplemental analysis include the estimated distribution of plant types as well as the facility emissions factors. An additional uncertainty associated with these analyses is the distribution of plant sizes. Although the types of plants used in the both analyses are based on a variety of reliable sources, including ICR responses for the Plating and Polishing NESHAP, trade association data, data from State agencies, and information from websites, we were unable to identify the plant type for nearly half of the data set. For those plants of unknown type, we used the highest emissions factor, which corresponds to a large hard chromium plant, in the conservative analysis. For the supplemental analysis, we developed an emissions factor using a weighted average across all plant types and sizes. For all plants that were modeled, weare soliciting additional information on actual and MACTallowable emissions, plant type, and plant size. More information about the development of the model plants can be

found in the “Model Plant Data Used to Estimate Risk from Chromium Electroplating Sources” document available in the1 4 docket for this action. In all the data sets, chromium compounds account for all the HAP emissions from the chromium electroplating and chromium anodizing source categories. For the Hard Chromium Electroplating source category, in the NEI-based data set, chromium VI compounds account for 98 percent of the emissions, with chromium III and chromium trioxide compounds comprising the remaining HAP. Here, we made the conservative assumption that 100 percent of the emissions are chromium VI compounds. For theDecorative Chromium Electroplating source category, in the NEIbased data set, chromium VI compounds account for 94 percent of the emissions, with chromium III and chromium trioxide compounds comprising the remaining HAP. Again, we made the conservative assumption that 100 percent of the emissions are chromium VI compounds. For the Chromium Anodizing source category, in the NEI-based data set, chromium VI compounds account for 99 percent of the emissions with chromium III compounds comprising the remaining HAP. In this case, we also made the conservative assumption that 100 percent of the emissions are chromium VI compounds. 3. What are the results of the risk assessments and analyses?

We conducted an inhalation risk assessment for each of the three source categories: Hard Chromium Electroplating, Decorative Chromium Electroplating, and Chromium Anodizing.1 5 Also, for each source category, we conducted an assessment of facility-wide risk, and performed a demographic analysis of population risks. As noted above, we developed two data sets for these source categories, one based primarily on NEI data for 166 sources, and one based on model plant data for 1,629

sources. The following tables present the combined results from the data sets. Table A.1 provides an overall summary of the maximum

individual inhalation risk assessment results and Table A.2 provides population risk assessment results for the Hard Chromium Electroplating, Decorative Chromium Electroplating, and Chromium Anodizing source categories. **Table A.1. Chromium Electroplating and Anodizing Maximum Individual Inhalation Risk Assessment Results**  Maximum individual cancer risk (in 1 million) 2 Maximum chronic non-cancer TOSHI 3 Source Category Number of Facilities (NEI/Model

Plant) 1 Actual Emissions

Level Allowable Emissions

Level Actual Emissions

Level Allowable Emissions

Level Maximum offsite acute non-cancer HQ 4

Hard Chromium Electroplating 63/1,219 70 90 0.06 0.09 Not appliacable 5 Decorative

Chromium Electroplating 96/337 70 70 0.06 0.06 Not appliacable 5 Chromium Anodizing 7/73 5 5 0.004 0.004 Not appliacable 5 1 Number of facilities evaluated in the risk analysis: the first number refers to the NEI data set, and the second number applies to the conservative emission estimate. 2 Maximum individual excess lifetime cancer risk. 3 Maximum target organ specific hazard index (TOSHI). The target organ with the highest TOSHI for the Hard Chromium Electroplating, Decorative Chromium Electroplating, and Chromium Anodizing source categories is the respiratory system. 4 The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of hazard quotient (HQ) values. HQ values shown use the lowest available acute threshold value, which in most cases is the REL. When HQ values exceed 1, we also show HQ values using the next lowest available acute threshold. See section IV.A. of this preamble for explanation of acute threshold values.1 6 5 NA = not applicable. There are no HAP with acute dose-response benchmark values, so no acute hazard quotients were calculated for these source categories. See section IV.A of this preamble for an explanation of acute threshold values. **Table A.2. Chromium Electroplating and Anodizing Population Risk Inhalation Risk Assessment Results** 

Conservative

Assessment Population

at risk Supplemental Assessment Population

at risk Source Category Number of Facilities (NEI/Model

Plant) ≥ 1-in-1 million ≥ 10-in1 million Conservative Annual cancer incidence ≥ 1-in-1 million ≥ 10-in1 million Supplemental Annual cancer incidence

Hard Chromium Electroplating 63/1,219 14,200,000 71,000 0.8 360,000 5,100 0.1

Decorative

Chromium Electroplating 96/337 390,000 4,000 0.08 30,000 1,300 0.01

Chromium Anodizing 7/73 2,700 0 0.003 540 0 0.001

As shown in Table A.1, the results of the inhalation risk assessment for the Hard Chromium Electroplating source category

indicate the maximum lifetime individual cancer risk could be as high as 70-in-1 million, based on actual emissions, and as high

as 90-in-1 million based on allowable emissions. This maximum individual cancer risk is based on the highest risk facility out of the 63 actual facilities and the 1219 model plants. The highest risk facility is one for which we have design and operating data, and we believe it is also both the largest and highest emitting hard chromium electroplating facility in the United States. Thus, we believe this level accurately reflects the maximum individual exposure. The maximum chronic non-cancer TOSHI value could be 0.06, based on the actual emissions level, and up to 0.09 based on allowables. This value is also based on known emission levels from the largest facility in the nation.1 7 A non-cancer TOSHI of one or less is not of human health

concern. The total estimated cancer incidence from hard chromium electroplating facilities based on actual emission levels is 0.8 excess cancer cases per year, or one case in every 1.25 years

for the conservative assessment. Our risk assessment shows 14.2 million people exposed to a cancer risk greater than 1-in-1 million and 71,000 people exposed to a cancer risk of at least

10-in-1 million. As noted above, we conducted a supplemental analysis to determine the weight to give to the conservative risk analysis. That supplemental analysis estimates 0.1 excess cancer cases per year, or one case in every 10 years. Additionally, it estimates a population exposure of 360,000 people at 1-in-1 million cancer risk. For a cancer risk of at least 10-in-1 million, the population exposed decreases to 5,100.

Based on the NEI data set for the decorative chromium electroplating source category, the maximum lifetime individual cancer risk could be as high as 70-in-1 million, and the maximum chronic non-cancer TOSHI value could be up to 0.06, based on the

actual emissions level. 2 We do not believe the maximum lifetime

individual cancer risk and the maximum chronic non-cancer TOSHI

2 There is uncertainty regarding the operating status of the facility associated with the maximum lifetime individual cancer risk. Prior to any final rulemaking action, we will investigate this situation and revise the risk analysis and results accordingly.1 8 value would be any higher than this based on allowable emissions. The total estimated population risks from the

conservative risk assessment of the decorative chromium electroplating facilities based on actual emission levels is 390,000 people exposed to a cancer risk greater than 1-in-1 million and 0.08 excess cancer cases per year, or one case in every 12 years. 3 Based on the NEI data set for the chromium anodizing source category, the maximum lifetime individual cancer risk could be as high as 5-in-1 million and the maximum chronic non-cancer TOSHI value could be up to 0.004, based on the actual emissions level. The total estimated population risks from the conservative assessment of the chromium anodizing facilities based on actual emission levels is 2,700 people exposed to a cancer risk greater than 1-in-1 million and 0.003 excess cancer cases per year, or one case in every 333 years. 4

3 Based on our conservative risk assessment, we believe the risks are low and as explained further below are proposing that the risks are acceptable for the decorative chromium source category. Although we did not need to consider the supplemental analysis that we conducted for decorative chromium to help guide our conclusion about the uncertainty of the risk assessment results, we note that the supplemental assessment shows 30,000 people exposed to a cancer risk greater than 1-in-1 million and 0.01 excess cancer cases per year, or one case in every 100 years. 4 Based on our conservative risk assessment, we believe the risks are low and as explained further below are proposing that the risks are acceptable for the chromium anodizing source category. Although we did not need to consider the supplemental analysis that we conducted for chromium anodizing to help guide our conclusion about the uncertainty of the risk assessment results, we note that the supplemental assessment shows 540 people exposed to a cancer risk greater than 1-in-1 million and 0.001 excess cancer cases per year, or one case in every 1000 years.1 9 Also, as there were no reported emissions of PB–HAP for these three source categories, we do not expect potential for human health multipathway risks or adverse environmental impacts. Our analyses of potential differences between actual

emission levels and emissions allowable under the MACT standards are based on emissions test data from specific facilities. A comparison of these test results to allowable emissions at these

facilities indicates that the ratio of MACT-allowable to actual emissions varies considerably from facility to facility. As a result, a uniform factor was not available to apply to all facilities. However, for the Hard Chromium Electroplating source category, we did evaluate the facility that was modeled as having the highest maximum individual lifetime cancer risk (70-in-1 million) based on actual emissions. Our analysis indicates that this facility, if operated at the allowable emissions limit, could have a maximum individual lifetime cancer risk as high as 90-in-1 million. Furthermore, the available data indicate that no other hard chromium electroplating facility would have a cancer risk that high if operated at the

allowable emissions limit. For the Decorative Chromium Electroplating source category, we performed a similar analysis of the available data and

concluded that the maximum individual lifetime cancer risk would2 0 not exceed 70-in-1 million for any facility that operated at the allowable emissions limit. As stated earlier, because most chromium anodizing facilities use WAFS, we believe actual emissions are essentially the same as allowable emissions. Thus, we believe that the MIR based on allowable emissions would be the same as that based on actual emissions, i.e., 5-in-a

million. Table A.3 displays the results of the facility-wide risk assessment for actual emissions of all sources at the facility as reported in the NEI. We did not perform a facility-wide risk assessment based on allowable emissions, as explained in the documentation referenced in section IV.A of this preamble, which

is available in the docket for this action. **Table A.3. Chromium Electroplating and Anodizing Facility-Wide Risk Assessment Results** 

Source Category Maximum Facility-Wide

Individual Cancer Risk (in 1 million) Source category contribution to this maximum facility-wide

individual cancer risk 1 Maximum Facility-WideChronic Noncancer TOSHI Source category contribution to this maximum facility-widechronic noncancer TOSHI 1 Hard Chromium Electroplating 90 <1% 2 <1% Decorative

Chromium Electroplating 90 7% 0.8 <1%

Chromium Anodizing 20 75% 0.2 <1%

1 Percentage shown reflects source category contribution to the maximum facility-wide risks at the facility with the maximum risk value shown. As shown in Table A.3, the maximum individual cancer risks from all HAP emissions at facilities that perform hard chromium2 1 electroplating, decorative chromium electroplating, and chromium anodizing are estimated to be 90-in-1 million, 90-in-1 million, and 20-in-1 million, respectively. For the facilities where these maximum risk values occur, the estimated proportion of the cancer risk attributable to the hard chromium electroplating, decorative chromium electroplating, and chromium anodizing processes is less than 1 percent, 7 percent, and 75 percent, respectively. The highest facility-wide cancer risk for a facility that includes a hard chromium electroplating source is primarily driven by chemical production processes. We are currently developing a chemical manufacturing sector project 5 and plan to address risk from these chemical production processes as part of that action. The highest facility-wide cancer risk for a facility that includes a decorative chromium electroplating source is primarily driven by aerospace processes that will be addressed in a future residual risk review for the Aerospace Manufacturing and Rework Facilities source category. The highest facility-wide cancer risk for a facility that includes a chromium anodizing source is primarily driven by the chromiumanodizing processes. The facility-wide maximum chronic noncancer TOSHI values for facilities that include Hard Chromium

5 This is one of several projects EPA is undertaking to establish and implement national emission-control measures for specific sectors of the economy by taking an integrated multipollutant approach to assessing and implementing additional emission controls using our existing regulatory frameworks.2 2 Electroplating, Decorative Chromium Electroplating, and Chromium Anodizing source category processes are estimated to be 2, 0.8, and 0.2, respectively. At the facilities where these maximum risk values occur, the estimated proportion of the non-cancer risk attributable to the Hard Chromium Electroplating, Decorative Chromium Electroplating, and Chromium Anodizing source category processes is less than 1 percent for each source category. The results of the demographic analyses performed to investigate the distribution of risks above 1-in-1 million, based on actual emissions levels for the population living within 5 km of the facilities, among various demographic groups are provided in a report available in the docket for this action and summarized in Tables A.4, A.5, and A.6 below. These estimates of total population with risk exceeding 1-in-1 million differ from the risk estimates presented above because the demographic analysis uses a 5 km radius and the risk assessment results provided above reflect use of a 50 km radius around all chromium electroplating facilities.

**Table A.4. Hard Chrome Electroplating Demographic Risk Analysis Results** 

Emissions Basis Maximum Risk Population With Risk Greater Than 1-in-1 million2 3 (in 1 million )

Total (mill ions) Ethnic Minorit y % A frican America n % Other and Multirac ial

% Hispani c or Latino % N ative America n % Below the Poverty

Level % O ver 25 W/O a HS Diplo

ma % Nationwid e n/a 285 25 12 12 14 0.9 13 13 Source Category 70 13.1 52 23 29 34 0.6 22 20Facilitywide 90 13.1 52 23 29 34 0.6 22 20 **Table A.5. Decorative Chromium Electroplating Demographic Risk Analysis Results** 

Population With Risk Greater Than 1-in-1 million

Emissions Basis Maximum Risk (in 1 million) Total (millio

ns) Ethnic Minorit y % A frican America n % Other and Multira

cial

% Hispani c or Latino % N ative America n % Below the

Pover

ty Level % Over 25 W/O a HS Diploma % Nationwid e n/a 285 25 12 12 14 0.9 13 13 Source Category 70 0.35 50 18 32 47 0.8 24 23Facilitywide 90 0.43 54 21 32 48 0.7 24 25

**Table A.6. Chromium Anodizing Demographic Risk Analysis Results**

Population With Risk Greater Than 1-in-1 million

Emissions Basis Maximum Risk (in 1 million) Total (millio

ns) Ethni c Minor

ity

% A frican America n % Other and Multirac ial

% Hispani c or Latino % N ative America n % Below the Pover

ty Level % Over 25 W/O a HS Diploma % Nationwid e n/a 285 25 12 12 14 0.9 13 13

Source Category 5 0.0027 36 16 0 0 0.4 25 19Facilitywide 20 0.0079 22 10 12 13 0.8 19 162 4 The results of the demographic analysis show that, for the population located within 5 km of hard chromium electroplating source category, there are about 13.1 million people with cancer risks greater than 1-in-1 million for both the source category and facility-wide. Of this population at risk, 52 percent could be classified as an “Ethnic Minority,” 34 percent are included in the “Hispanic or Latino” demographic group, 29 percent are included in the “Other and Multiracial” demographic group, 23 percent are included in the “African-American” demographic group, 22 percent are included in the “Below Poverty Level” demographic group, and 20 percent are included in the “Over 25 Without a High School Diploma” demographic group. The percentage of the population within 5 km of a hard chromium electroplating facility and with a cancer risk greater than 1- in-1 million is higher than the typical distribution of risks to these demographic groups across the United States. These demographic analyses are based on the conservative assessment

results. For the Decorative Chromium Electroplating source category, there are about 350,000 people with cancer risks greater than 1- in-1 million for the source category and 430,000 people with cancer risks greater than 1-in-1 million facility-wide. Of this population at risk, 50 percent could be classified as an “Ethnic Minority” 47 percent are included in the “Hispanic or Latino”2 5 demographic group, 32 percent are included in the “Other and Multiracial,” demographic group, 18 percent are included in the “African-American” demographic group, 24 percent are included in the “Below Poverty Level” demographic group, and 23 percent are included in the “Over 25 Without a High School Diploma” demographic group. The percentage of the population within 5 km of a decorative chromium electroplating facility and with a cancer risks greater than 1-in-1 million is higher than the typical distribution of risks to these demographic groups across the United States. The results of the demographic analysis for facility-wide emissions are similar to the results for the source category. For the Chromium Anodizing source category, there are about 2,700 people with cancer risks greater than 1-in-1 million and 7,900 people with cancer risks greater than 1-in-1 million facility-wide. Of the population with cancer risks greater than 1-in-1 million, 36 percent could be classified as an “Ethnic Minority,” 16 percent are included in the “African-American” demographic group, 25 percent are included in the “Below Poverty Level” demographic group, and 19 percent are included in the “Over 25 Without a High School Diploma” demographic group. The percentage of the population within 5 km of a chromium anodizing facility and with a cancer risk greater than 1-in-1 million is higher than the typical distribution of risks to these2 6 demographic groups across the United States. The results of the facility-wide demographic analysis are higher than the typical distribution of risks to the demographic groups across the United States, for the “Below Poverty Level” and the “Over 25 Without a High School Diploma” demographic groups, but are lower than these levels for the other demographic groups. Details of these assessments and analyses can be found in

the residual risk documentation as referenced in section IV.A of this preamble, which is available in the docket for this action. 4. What are our proposed decisions on risk acceptability and ample margin of safety? a. Risk Acceptability. The risk analysis we performed for this proposal indicates that for the hard chromium electroplating source category, the cancer risks to the individual most exposed is 70-in-1 million

based on actual emissions and 90-in-1 million based on MACTallowable emissions. The maximum noncancer risk level, which is low, is a TOSHI of 0.06 based on actual emissions and 0.09 based

on allowable emissions. These risks are due to estimated emissions of hexavalent chromium, which EPA describes as a known human carcinogen by the inhalation route of exposure. As explained above, both the MIR and the maximum noncancer risk

levels are based on emissions from what we believe is the2 7 highest risk hard chromium facility operating in the United

States.

We further estimate that the excess cancer incidence could be as high as 0.8 cases per year and that over 14 million people could be exposed to a cancer risk of 1-in-1 million or greater. These risk levels are based on a highly conservative risk assessment as described above. In summary, in this assessment we used (1) actual emissions data for 63 facilities and (2) emissions estimates that are reflective of average emissions for the highest emitting facilities for each one of an additional 1,219 facilities. Because there are only 790 hard chromium facilities and because only ten percent of the facilities would have this high of an emissions rate, we believe that these

conservative risk assessment results overstate cancer incidence and population exposure. As noted above, we performed a supplemental analysis to assess the degree to which the conservative risk assessment may overstate risks, and thus to determine how heavily to weigh those risks in determining whether to find the risks acceptable. In this supplemental analysis we assessed these risks based on (1) the emission data used in the conservative assessment for the 63 facilities for which we have actual facility emission information, and (2) revised emission data that better represent nationwide average emission levels for the 1,219 facilities.2 8 The supplemental assessment indicates that the excess cancer risks from hard chromium electroplating facilities is 0.1 cancer cases per year and 360,000 people exposed to a cancer risk of 1- in-1 million or more, which is substantially less than we found

with the conservative assessment. These results indicate that the estimated risks are uncertain and are highly sensitive to input assumptions and that the conservative assessment may substantially overstate risks. The results of our demographic analysis indicate that minorities face disproportionate risk from exposure to emissions from this category (Tables A.3 – A.5). Although the demographic analysis was based on our conservative risk assessment modeling,

we have no reason to believe that the results would be substantially different were we to re-run that analysis using the assumptions underlying the supplemental assessment. This is because the disparate impacts identified through our demographic analysis are reflective of the fact that many chrome facilities are located in inner city urban areas, and in or near residential neighborhoods more likely to be inhabited by minority and low income persons. We are concerned about the potential disproportionate health risks from these urban facilities on minorities and those below the poverty level. We solicit comment on whether there may be pollution prevention efforts or other HAP emission reduction approaches that could2 9 mitigate the impacts that these facilities have on their immediate surroundings. We also recognize that in addition to whatever controls are required in the final rulemaking for the hard chromium electroplating category, there may be other approaches, such as facility-specific compliance assistance, that could mitigate the impacts that these facilities have on their immediate surroundings. We solicit comment and supporting information to assist EPA in identifying measures to mitigate these disproportionate risks. In accordance with the approach established in the Benzene NESHAP, EPA weighed all health risk measures and information, including the maximum individual cancer risk, the cancer incidence, the number of people exposed to a risk greater than 1-in-1 million, the distribution of risks in the exposed population, and the uncertainty of our risk calculations, in determining whether the risk posed by emissions from hard chromium facilities is acceptable. As an initial matter, we note that the 90-in-1 million risk based on allowable emissions is approaching the “presumptive limit on maximum individual lifetime risk of approximately 1 in 10 thousand [100-in-1 million]” recognized in the benzene NESHAP (54 FR 38045). We also note that, based on our conservative analysis, there is a high level of cancer incidence of 0.8 and a very large number (14.2 million) of people potentially exposed3 0 to a cancer risk greater than 1-in-1 million. However, we also recognize that our supplemental assessment based on alternative input assumptions concerning emissions (that better represent nationwide average emissions) indicate that the results of the conservative assessments are substantially overstated. Thus, there is great uncertainty about both the cancer incidence and the number of people exposed. On the one hand, we acknowledge that the cancer incidence and number of people exposed to cancer risks of 1-in-1 million or greater are high based on our conservative analysis. On the other hand, we recognize the significant uncertainty of these risk estimates and the likelihood that they are overstated,

based on the conservative nature of the assessment. The supplemental analysis highlights the sensitivity of our risk analysis to highly uncertain input assumptions and supports a determination that the population exposure and cancer incidence risk numbers are overstated. It shows substantially lower cancer incidence (0.1 cases per year as opposed to 0.8) and number of people potentially exposed to a cancer risk of 1-in-1 million or more (360 thousand as opposed to 14.2 million). In addition, the distribution of risks in the exposed population shows the number of people exposed to a cancer risk greater than 10-in-1 million is 71,000 for the conservative assessment and 5,100 for the supplemental analysis.3 1 In determining whether risk is acceptable, we focus on the results of all aspects of the risk assessment. Because the MIR is less than 100-in-1 million and because of the significant uncertainty of the cancer incidence and number of people exposed, which, as explained above, we believe are overstated based on the fact that our risk analysis was highly conservative, at this time, we are proposing that the risks from the hard chromium electroplating source category are acceptable. We are proposing that the risks are acceptable, in large part, because we believe that the assumptions underlying the supplemental analysis may present a more realistic estimate of

the emissions from hard chromium facilities. However, we are very concerned by the results of our conservative risk analysis, especially the large number of people (including disproportionately affected populations) estimated to be exposed at a cancer risk above 1-in-1 million. We are also concerned about the level of uncertainty with our analysis given that we have very limited information as to the number (and size) of the facilities. While our current proposal is supported by recognizing the uncertainty associated with the high risk levels from our conservative assessment and, as explained above, that uncertainty (as demonstrated by the supplemental analysis) points in the direction of an overstatement of risk, we would prefer to base a final rule on3 2 more complete and reliable information. In this case, we recognize that the assessment may be overly conservative and we are considering additional methods for performing a conservative analysis. However, we believe additional information and data regarding the location, type and size of facilities will be important to performing any additional analysis that would err on the side of protectiveness without being overly conservative. At this time, we are not certain that we would take final action finding the risk to be acceptable based on the limited information currently available to the Agency.

The comments and information that we receive on this proposal will be critical in making a final decision on acceptability. We are soliciting comment and data to help the Agency make an informed decision as it moves forward with this rulemaking. Specifically, with regard to each of the facilities listed in Appendix A to this preamble, we are seeking to identify (1) the actual annual emissions, if known; (2) which of the three source categories it falls within; and (3) whether, for hard chromium, it is a “large” or “small” facility within the definitions in 40 CFR 63.341(a). In particular, we are encouraging the States to provide EPA with better inventory data for sources within their states. Moreover, we are encouraging States to help identify sources that may be located near sensitive populations, such as located near schools or that may3 3 be located in communities with a significant minority population. To feel comfortable with a final decision finding the risk acceptable, we believe it is important to reduce the level of uncertainty associated with our current analyses. Thus, in light of the comments and any additional data (or lack thereof) that we receive during the comment period, we may determine that it is appropriate to issue a supplemental proposal in which we propose to find the risk unacceptable. If we issue a supplemental proposal in which we propose to find the risk unacceptable, we would be required to propose emissions standards or work practices that reduce risk to a level that is acceptable and provides an ample margin of safety. We note that we have a proposed draft Consent Decree,

Sierra Club v. EPA (N.D. Cal., No. 09-cv-00152SBA) (Consent Decree lodged with Court on July 6, 2010), which would require us to take final action under CAA 112(f)(2) for the Chromium Electroplating source category by June 30, 2011. If, after the close of the comment period, we conclude that it is necessary to issue a supplemental proposal, we would plan to seek an extension of that Consent Decree deadline to provide sufficient time for that process. For the decorative chromium electroplating source category, the cancer risks to the individual most exposed is 70-in-1

million based both actual and MACT-allowable emissions. Based3 4 on this cancer risk level and in consideration of other health measures and factors, including the cancer incidence (one case in every 12.5 years) and the low maximum noncancer risk level (TOSHI of 0.06 based on both actual and MACT-allowable emissions), we propose that the risks from the decorative chromium electroplating source category are acceptable. For the chromium anodizing source category, the cancer risks to the individual most exposed is 5-in-1 million based on

both actual and allowable emissions. Based on this low cancer

risk level and in consideration of other health measures and factors, including the cancer incidence (one case in every 250 years) and the low maximum noncancer risk level (TOSHI of 0.004 based on actual emissions), we propose that the risks from the chromium anodizing source category are acceptable. b. Ample Margin of Safety. Although we are proposing that the risks from these source categories are acceptable, risk estimates for individuals in the exposed population are above 1-in-1 million. Consequently, we considered whether the MACT standard provides an ample margin of safety. As part of this analysis, we investigated available emissions control options that might reduce the risk associated with chromium compound emissions from hard chromium electroplating, decorative chromium electroplating, and chromium3 5 anodizing operations. Table A.6 summarizes the nationwide costs and cost effectiveness of these regulatory control options. **Table A.6. Costs of Control Options for Chromium Electroplating**

**Type of facility**  **Control Option**  **Number of Affected**  **Facilities Emission**  **reduction (TPY)**  **Capital costs**  **($million) Annualiz**  **ed costs ($millio** 

**n/yr) Cost**  **effectiven ess**  **($million/ ton)**  **MIR After Control**  **(** in-amillion) Large hard chromium electroplating HEPA filter retrofit 132 1.0 35.1 18.4 17.7 6

HEPA filter retrofit 658 0.4 66.0 33.9 84.9 6 Small hard chromium electroplating CMP retrofit 392 0.2 36.6 11.1 59.7 10

HEPA filter retrofit 740 0.1 109.0 50.6 513.9 4 Decorative chromium electroplating CMP retrofit 644 0.05 1 41.3 22.2 886.1 10

HEPA filter retrofit 240 0.02 43.9 18.9 945.0 < 1 Chromium anodizing CMP retrofit 198 0.009 1 16.1 7.4 1860 2

1 Based on an estimated control efficiency of 99.9 percent. For large hard chromium electroplating facilities, we

evaluated the costs and emissions reductions associated with retrofitting existing tanks with HEPA filters. For small hard chromium electroplating facilities, we evaluated the same HEPA filter retrofit option and also the option of retrofitting CMP systems on all tanks currently controlled with packed bed scrubbers. Retrofitting HEPA filters on existing tanks at large hard chromium electroplating plants would reduce nationwide emissions of chromium compounds by an estimated 1.04 TPY from the estimated baseline level of 1.10 TPY. The estimated capital and annualized costs for this option would be $35,100,000 and $18,430,000, respectively. The cost effectiveness would be $17,700,000 per ton of HAP emissions reduced. Retrofitting HEPA3 6 filters on existing tanks at small hard chromium electroplating plants would reduce nationwide emissions of chromium compounds by an estimated 0.40 TPY from the estimated baseline level of 0.42 TPY. The estimated capital and annualized costs for this option would be $65,980,000 and $33,860,000, respectively. The cost effectiveness would be $84,900,000 per ton of HAP emissions reduced. Retrofitting CMP systems on all tanks currently controlled with packed bed scrubbers at small hard chromium electroplating plants would reduce nationwide emissions of chromium compounds by an estimated 0.19 TPY from the estimated baseline level of 0.37 TPY. The estimated capital and annualized costs for this option would be $36,640,000 and $11,050,000, respectively. The cost effectiveness would be $59,700,000 per ton of HAP emissions reduced. The Benzene NESHAP emphasizes the need to consider “costs and the economic impacts of control” which implies some knowledge of affordability (54 Fed. Reg. 38046). The cost of the control options for hard chromium electroplating would impact over half of these facilities with estimated cost to sales ratios ranging from 8% to 22%. A cost to sales ratio greater than 3% may have a significant impact, including plant closure for many of these

facilities. These additional control requirements would reduce the

maximum lifetime individual cancer risk from the Hard Chromium3 7 Electroplating source category to approximately 4-in-1 million,based on actual emissions. We estimate that considering MACTallowable emissions levels, the maximum lifetime individual cancer risk from the Hard Chromium Electroplating source category would be reduced to approximately 6-in-1 million. The cancer incidence would be reduced to approximately 0.05 and the estimated number of people exposed higher than 1-in-1 million

would be about 1 million. For decorative chromium electroplating, we evaluated the options of retrofitting HEPA filters on all existing tanks and the option of retrofitting CMP systems on the existing tanks that currently are not equipped with add-on control devices. Retrofitting HEPA filters on all existing decorative chromium electroplating tanks would reduce nationwide emissions of chromium compounds by an estimated 0.098 TPY from the estimated baseline level of 0.10 TPY. The estimated capital and annualized costs for this option would be $108,970,000 and $50,600,000, respectively. The cost effectiveness would be $513,900,000 per ton of HAP emissions reduced. Retrofitting CMP systems on all decorative chromium electroplating tanks that currently do not have add-on controls would reduce nationwide emissions of chromium compounds by an estimated 0.05 TPY from the estimated baseline level of 0.10 TPY. The estimated capital and annualized costs for this option would be $41,300,000 and3 8 $22,190,000, respectively. The cost effectiveness for this option would be $886 million per ton of HAP emissions reduced. The additional control requirements for HEPA filters would

reduce the maximum lifetime individual cancer risk from the Decorative Chromium Electroplating source category to approximately 4-in-1 million, based on actual emissions. Because we believe the actual emissions are essentially the same

as the MACT-allowable emissions for the Decorative Chromium Electroplating source category, we estimate no difference

between the risk from the allowable emission level and the

actual emission level. For chromium anodizing, we evaluated the options of retrofitting HEPA filters on all existing tanks and the option of retrofitting CMP systems on the existing tanks that currently are not equipped with add-on control devices. Retrofitting HEPA filters on all existing chromium anodizing tanks would reduce nationwide emissions of chromium compounds by an estimated 0.020

TPY from the estimated baseline level of 0.021 TPY. The estimated capital and annualized costs for this option would be$43,860,000 and $18,860,000, respectively. The costeffectiveness would be $944,800,000 per ton of HAP emissions reduced. Retrofitting CMP systems on all chromium anodizing tanks that currently do not have add-on controls would not significantly reduce emissions. The estimated capital and3 9 annualized costs for this option would be $16,130,000 and $7,430,000, respectively. The cost effectiveness for this option would be $1,860 million per ton of HAP emissions reduced. The additional control requirements for HEPA filters would

reduce the maximum lifetime individual cancer risk from the Chromium Anodizing source category to less than 1-in-1 million,

based on actual emissions. Because we believe the actual emissions are essentially the same as the MACT-allowable emissions for the Chromium Anodizing category, we estimate the

risk reduction based on allowable emissions to be the same as

that for the actual emissions. Our risk analysis results show cancer risks to the individual most exposed of 70-in-1 million and 5-in-1 million based on actual and MACT-allowable emissions, respectively, for the Decorative Chromium Electroplating and Chromium Anodizing source categories. For both of these categories, the cancer incidence is less than 0.01 cases/year. For decorative chromium electroplating, the number of people exposed to a cancer risk of 1-in-1 million or more is approximately 390,000. For chromium anodizing, the number of people exposed to a cancer risk of 1- in-1 million or more is approximately 2,700. For the Hard Chromium Electroplating source category, our risk analysis shows cancer risks to the individual most exposed

are 70-in-1 million based on actual emissions levels and 90-in-14 0 million based on MACT-allowable emissions. The cancer incidence for this source category could be as high as 0.8 cases/year, andcould be over 14 million people exposed to cancer risks of 1-in1 million or greater due to emissions from hard chromium electroplating sources using highly conservative assumptions. As we stated previously, we believe we overestimated hard chromium electroplating emissions, the number of plants that perform hard chromium electroplating, and therefore that the risks from the resulting analyses are also overstated. Our supplemental risk analysis for this source category indicates a cancer incidence of 0.1 cases/year and 360,000 people exposed to cancer risks of greater than 1-in-1-million. This analysis indicates that the risk levels in the assessment are highly uncertain and err on the side of being conservative. Our analyses also show that, for these source categories, there is no potential for an adverse environmental effect or human health multipathway effects, and that acute and chronic non-cancer health impacts are unlikely. Our additional analysis of facility-wide risks showed that the maximum facility-wide

cancer risk is 90-in-1 million and that the maximum chronic noncancer risks are unlikely to cause health impacts. Our additional analysis of the demographics of the exposed population shows that minorities face disproportionate risk from exposure to emissions from this category4 1 We do not believe there is a significant risk reduction from the housekeeping measures we are proposing under 112 (d)(6). However, we are requesting information on any risk reductions from these housekeeping practices and whether we should consider adopting these practices under 112 (f)(2). We considered all these factors in our ample margin of safety decision, and concluded that the costs of the options analyzed are not reasonable considering the emissions reductions and cancer health benefits potentially achievable with the controls. As a result, we propose that the existing MACT standard provides an ample margin of safety (considering cost, technical feasibility, and other factors) to protect public health for all three of these source categories. Thus, we are proposing to re-adopt the existing MACT standard to satisfy section 112(f) of the CAA. While we propose that the existing MACT standard for the hard chromium electroplating source category is acceptable and provides an ample margin of safety, we are proposing additional requirements under CAA section (d)(6), as discussed below. Notwithstanding our proposal that the risks are acceptable, we remain concerned that up to 14.2 million people may be exposed to cancer risks of 1-in-1 million or greater and that there are disparities in risks for some demographic groups. While we are rejecting the option of adding HEPA filters or composite mesh4 2 pads as not cost-effective, we are specifically requesting comment on whether there are any cost-effective controls that may be able to reduce these risks. In particular, we are requesting States to identify any controls they have already required for these facilities, any controls they are currently considering, or any other controls of which they may be aware. We are also soliciting comment on whether our cost estimates for these options are accurate and whether these controls may be

more cost-effective. In summary, we propose that the risks posed by these source categories are acceptable. We are also proposing that the current MACT standard provides an ample margin of safety to protect public health based on our conclusion that the controls available are not cost-effective in light of the additional health protection the controls would provide. Thus, we are proposing to re-adopt the existing MACT standard to satisfy section 112(f) of the CAA.