Summary of Comments and Responses for the Primary Aluminum Reduction Plants

Source Category: Risk and Technology Review, Phase II, Group 2

Advance Notice of Proposed Rulemaking (72 FR 14734, March 29, 2007)

Metals and Minerals Group

Sector Policies and Program Division

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

November 16, 2009
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INTRODUCTION

This document provides a summary of comments received for the Advance Notice of 

Proposed Rulemaking (ANPR) for the Risk and Technology Review for the Primary Aluminum 

Reduction Plants (72 FR 14734, March 29, 2007). It also includes comments on POM emissions 

and speciation solicited by EPA from industry after the ANPR that was needed for the emissions

database to be used for future risk modeling for the proposed rule. The EPA responses to the 

comments follow the comments below, as appropriate. All commenters are listed in Table 1. The 

majority of comments focused on corrections to the National Emissions Inventory (NEI) database 

for specific primary aluminum reduction plants.

Table 1. List of Commenters for Primary Aluminum NESHAP ANPR and 

Revised Emissions Modeling Database 

ANPR Commenters

Commenter 

Number*- Commenter Affiliation

0013 Brian Galley Pechiney Plastic Packaging, Inc.

0014 Tim Adamowicz Ormet Primary Aluminum

0015, 0022 Sean Lane Century Aluminum

0016 Jamie Coomes ALCAN Primary Products

0017 Robert Strieter The Aluminum Association

0018 Keith Overcash North Carolina Department of Environment and Natural Resources

0019 Brandy Albertson Oregon Department of Environmental Quality

0020 David Shaw New York State Department of Environmental Conservation

0021 Michael Palazzolo ALCOA

0023 Michael Palazzolo ALCOA

Commenters on Revised Emissions Modeling Database

0024** Michael Palazzolo ALCOA

0025** Michael Palazzolo ALCOA

0026** Michael Palazzolo ALCOA

0027 Michael Palazzolo ALCOA

0028 Robert Strieter The Aluminum Association

0029 Steve Wright Columbia Falls Aluminum Company

0030 Michael Palazzolo ALCOA

* Docket numbers for these comments use the above 4 digits with the prefix: EPA-HQ-QAR2002-0031-XXXX.

** Test reports for sampling and analysis of polycyclic aromatic hydrocarbons.
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NATIONAL EMISSION INVENTORY (NEI) COMMENTS

General Inventory Comments

Comment: All of the commenters shown in Table 1 above provided changes to the NEI database, 

and the most extensive changes were requested by Commenter 0021, whose company owns or 

operates 10 of the 16 primary aluminum plants in the U.S.

 Examples of changes provided by Commenter 0021 for the NEI database include:

 Identifying plants, potlines, and other operations that have shut down;

 Removing emission points and emissions associated with secondary aluminum production; 

and

 Correcting stack gas parameters, stack diameters and heights, stack latitudes and longitudes.

Response: The changes provided by the commenters were reviewed, and changes were made to 

update the NEI based on the corrected site-specific data from the commenters, as detailed in 

Appendix A. We also investigated other deficiencies in the NEI database identified by the 

commenters and gathered information to fill in data gaps. A listing of these other improvements 

made to the NEI database, in large part due to observations of reviewers and commenters, are also 

noted in Appendix A.

Comment: Commenters 0017 and 0021 claimed that the preliminary risk review incorrectly 

identified HCl and mercury as key pollutants causing potential health risks from primary aluminum 

plants. The commenters noted that emissions of HCl are more commonly associated with 

secondary aluminum processes, and emissions of mercury are associated with coal-fired power 

plants.

Response: We have confirmed that the HCl emissions in the preliminary analysis were from 

secondary aluminum production, and we have removed secondary aluminum emissions from the 

primary aluminum database. We also confirmed that a majority of the mercury emissions were 

from a coal-fired power plant co-located with a primary aluminum facility; these mislabeled 

emissions have been removed from the modeling database. 

Comment: Two commenters (0027, 0028) recommended using 100 percent utilization of capacity 

to estimate both “actual” and “allowable” emissions. The commenters explained that although a 

few plants are operating at less than 100 percent due to current economic conditions, many are 

operating at 100 percent, and those that are not will increase to 100 percent in future years as 

economic conditions improve. 

Response: EPA agrees with the commenters, since using an industry-wide average of 76 percent 

utilization could underestimate emissions for many plants. Therefore, POM and other emission 

estimates will be based 100 percent utilization of capacity. 

Comment: Commenter 0021 stated that even with the extended comment period, there was not 

enough time to fully review and update the NEI database. The commenter asked that EPA not 

preclude the submission of supplemental data after the end of the comment period.
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Response: We continued to work with this commenter, as well as other industry representatives 

and the trade association, after the end of the comment period. The commenter continued to 

provide additional data from his company’s environmental professionals, and we have incorporated 

these improvements into the database. As noted below, additional opportunities were provided for 

industry representatives to review the changes made to the database with a particular emphasis on 

filling in data gaps for emissions of POM species.

Polycyclic Organic Matter (POM) Comments

Comment: Commenter 0021 provided speciated data for polycyclic organic matter (POM), 

corrected emission estimates, added emission estimates that were missing, and separated total 

emissions to identify emissions from individual potlines and roof vents.

Comment: Commenter 0020 said that POM emissions were not included for two plants in their 

State and asked that the POM emission estimates be added.

Response: The data provided by the commenters, above, indicated that many plants had not 

included emissions of POM species. EPA compiled data for POM species for the different types of 

processes, developed emission factors, and applied these factors to estimate emissions for POM 

species. The methodology and estimates were sent to industry representatives and the trade 

association for their review. Revisions were made by EPA based on their review comments, and 

the POM database was sent for a second review. We incorporated the few minor additional 

comments received from one company during the second review (0030).

Comment: One commenter (0027) submitted test results to estimate POM emissions from 

horizontal stud Soderberg (HSS) plants. (See Docket Item 0025.) 

Response: EPA has replaced the estimated POM emissions from the HSS plant based on the 

comments, since the commenter (ALCOA) has the only existing HSS plant, and the test results are 

specifically for that plant. The data used previously in the EPA estimates were from a plant that has 

permanently closed.

Comment: One commenter (0029) submitted POM estimates for vertical stud Soderberg (VSS) 

plants. This facility is the only VSS plant currently operating. The data were based on several 

years of site-specific testing results submitted by the facility for methylene chloride soluble organics 

(MCSO), which are the surrogates used for POM.

Response: EPA adjusted the POM estimates for vertical stud Soderberg (VSS) plants, since this 

facility is the only VSS plant currently operating. 
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MODELLING COMMENTS

Comment: Commenters 0017 and 0021 said that EPA’s use of AERMOD to evaluate risk from 

potline fugitive emissions is inappropriate because it does not contain or make use of the Buoyant 

Line and Point (BLP) source algorithms required to properly model 300-m long roof vents with 

multiple emission points. The commenters recommended using the BLP or CALPUF models.

Response: These initial ANPR results are a screening assessment. If needed, EPA will look at 

some facilities on a more refined level, such as using BLP, before we get to the final rulemaking 

phase of the residual risk analysis. The EPA took a similar approach for the coke ovens rulemaking 

to use the BLP to predict plume rise for coke batteries. Also, EPA has some strategies for entering 

data from line sources so that the air model represents them accurately: split the emissions into a 

group of points so that the plume rise from the hot plumes can be captured; and/or modify the NEI 

emission inventory input file with a change to the model source inputs and make it as multiple area 

or point source release points to better represent a line source emission.

RISK ASSESSMENT COMMENTS

Comment: Commenters 0017 and 0021 stated that it was not appropriate to multiply the average 

emission rate by a factor of 10 to evaluate acute (1-hr) exposures. The commenters said that 

potroom control devices, paste plants and anode bake furnaces are steady state operations, 

emissions that do not vary much from average values, and no safety factor should be applied. 

However, the commenter also stated that emissions increase from potroom vents during carbon 

setting and metal tapping and recommended a factor of 4 to 6 times the average to estimate hourly 

roof emissions.

Response: The suggestions for acute exposure factors suggested by the commenters will be used 

by the EPA to develop the factors to be used in the risk analysis performed for the proposed rule. 

The initial factor used by EPA for the ANPR risk analysis was a default that was considered

reasonable in the absence of industry-specific information. The public will have additional 

opportunity to comment on the factors used by EPA in the proposal comment period.

Comment: Commenter 0020 recommended that the risk evaluation be based on the facility’s

actual maximum emissions if not potential emissions. The commenter cited an example of one 

plant that reported carbonyl sulfide emissions of 173 tons per year in the 2002 NEI whereas the 

Toxics Release Inventory (TRI) shows 285 tons per year. The commenter also said that another

plant had similar stack emissions reported in both the NEI and TRI; however, the fugitive emissions 

in the TRI were 20 times greater than those reported in the NEI.

Response: We plan to perform more refined modeling based on both “actual” emissions as 

reported by the companies and States, and “allowable” emissions, which are the maximum 

emissions permitted under the current regulations. The maximum or “potential” emissions 

recommended by the commenter are comparable to the allowable emission estimates.
Appendix A 

Details of Revisions to the NEI Database for Primary Aluminum

Based on ANPR Comments and Subsequent Industry Review and Comment 

on the Modeling Database

1. Incorporated changes in emission points, stack characteristics, locations, etc., according 

to facility comments.

2. Corrected facility names, facility operating status, and operating parameters:

 Deleted Reynolds (Troutdale) and Northwest Aluminum because they have 

permanently closed. 

 Deleted Alcan Packaging because it is not an aluminum plant.

 Updated name changes for mostly ALCOA acquisitions, and Century Aluminum.

 Adjusted the capacity of the ALCOA plant in Badin, NC to 60,000 metric 

tons/year because one of the potlines has been permanently shut down.

 Revised (upwards) the aluminum and paste plant capacities for Columbia Falls 

based on their comments.

 Changed the tons anode per ton aluminum ratio from 0.5 to 0.57 tons anode/ton 

aluminum based on comments from the Aluminum Association and ALCOA.

3. Checked emission points for completeness, e.g., most were missing the paste plant. 

Added emission units that were missing. 

 Information for three plants was particularly incomplete: Columbia Falls (only 

one emission point entry, unidentifiable); Century Aluminum in WV; and Lake 

Charles Carbon. EPA obtained their Title V permits and entered emission point 

data that were available. 

 Removed emissions for a paste plant at ALCOA (West) Massena, NY, because it 

is no longer operating since the facility now purchases anodes from a company in 

Canada.

4. Reviewed and corrected the default stack characteristics for reasonableness: 

 Revised several default entries that had stack diameters of 0.003 ft and 5,060 ft, 

which did not seem reasonable. 

 Compiled stack characteristics by type of process and averaged them. Filled in 

any missing stack characteristics with the overall averages for height, 

temperature, diameter, and velocity. Calculated volumetric flow from diameter 

and linear velocity to be consistent. 

 Commenter 0030 provided latitude and longitude data for potroom roof vents for 

several ALCOA plants.

5. Developed emission factors and estimates of POM species for the different types of 

processes. Industry representatives and the trade association provided review. The 

following changes were made based on the review comments:

 Revised the POM emission estimates on 100% utilization of capacity.

 Used test results submitted by ALCOA to estimate POM emissions from 

horizontal stud Soderberg (HSS) plants.

 Adjusted the POM estimates for Columbia Falls Aluminum’s VSS facility based 

on several years of site-specific testing results provided by the facility.