1 MEMORANDUM

Date: September 16, 2013

TO: Docket No. EPA

- HQ

- OAR

- 2012

- 0510: National Emissions Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production

FROM: Kaye Whitfield, EPA/OAQPS/SPPD

SUBJECT: MACT

- Allowable Emissions for the Flexible Polyurethane Foam Production Source Category

_________________________________________________________________________________ The purpose of this memorandum is to present analyses related to “MACT

- allowable” emissions levels and risks for the Flexible Polyurethane Foam (FPUF) Production source categor y that is being addressed under the EPA’s R e s i d u a l Risk and Technology ( R T R ) r eview program.

The RTR program is addressi ng the statutory requirements in section 112(f) and 112(d)(6) of the Clean Air Act for federal air toxics regulations. The regulations are National Emission Standards for Hazardous Air Pollutants (NESHAP) contained in 40 CFR part 63 , which are commonly ref erred to as Maximum Achievable Control Technology (MACT) standards. The emissions data being u sed for the RTR risk assessment for this categor y consist of data representative of “actual” emission levels. In addition to the risks associated with these actua l emission levels, the EPA also considers th e levels of HAP emissions that facilities could emit and still be in compliance with the applicable MACT regulation. These emission levels are referred to as “MACT

- allowable” emissions. The purpose of this memora ndum is to discuss these MACT

- allowable emission levels and to relate the potential risks if facilities emitted at these levels.

This memorandum is organized as follows. Section 1 presents the estimated maximum risk levels based on the actual emission levels for the source category, and Section 2 discusses the source category. Section 3 presents the approach to estimating the risks at the MACT

- allowable levels. This is followed by a discussion of the estimation of the MACT

- allowable emission level for the FPUF Production MACT standard s in Section 4

. Section 4 also includes a presentation of the estimated risks at the estimated MACT

- allowable emissions levels.

1.0 Risk Levels Based on Actual Emissions

The estimated maximum inhalation risks for the sou rce categor y are summarized in Table 1. These risks are based on actual emission levels.2 Table 1. Summary of Estimated Inhalation Risks for the FPUF Production Source Category Based On Actual Emissions Levels

Source Category Maximum individual cancer risk (in a million) 1 Maximum chronic

noncancer TOSHI 2 Maximum acute HQ 3
Flexible Polyurethane Foam Production (FPUF) 0.7 0.9 0.9

1 Maximum individual excess lifetime cancer risk.
2 Maximum target organ specific hazard index (TOSHI). The m aximum TOSHI is based on respiratory effects.
3 Maximum acute Hazard Quotient (HQ).

2.0 Source Category Background

The FPUF Production MACT standards address three subcategories of FPUF production facilities: slabstock foam production facilities, molded foam production facilities, and rebond foam production facilities. We estimate there are currently 7 slabstock foam production facilities, 6 molded foam production facilities, and 2 rebond foam production facilities (th ese 2 rebond facilities are co

- located with other slabstock or molded foam facilities) operating in the U.S. that are subject to the FPUF Production MACT standards. For these different facility types, the FPUF production MACT standards include requirement s for the following types of emission sources: (1) storage vessels, (2) equipment leaks, (3) foam production lines, (4) equipment cleaning, and (5) mold release agents. Table 2 summarizes the formats of the standards for these emission points.

Table 2. Formats of Standards for the FPUF P r o d u c t i o n NESHAP

FPUF Production Subcategory Emission Source Type Format of Primary Standard

Slabstock Storage Vessels Equipment Standards, Work Practice Standards Equipment Leaks Equipment Standards, Work Practice Standards

Production Line Performance Standard (HAP Auxiliary Blowing Agent (ABA) formulation limits) Equipment Cleaning HAP Use Prohibition a

Source

- wide emission limit alternative Alternative limit for all HAP ABA storage, equipment leaks, equipment cleaning and production line emissions Molded Equipment Cleaning HAP Use Prohibition b Mold Release Agents HAP Use Prohibition Rebond Equipment Cleaning HAP Use Prohibition Mold Release Agents HAP Use Prohibition

a The NESHAP contains an exception that allows HAP to be used in cleaning if the same HAP is used as an ABA and for cleaning equipment and if the source

- wide emission limit alternative is chosen.
b The NESHAP contains an exception that allows diisocyanates to be used to flush certain equipment during startup or maintenance if the diisocyanates are in a closed

- loop system and are re

- used in production.3 With the MACT standards in place, there are no HAP emissions allowed from equipment cleaning or mold relea se operations at molded and rebond foam production facilities. For slabstock foam production

, HAP emissions of toluene diisocyanate (TDI) , which is used in the foam production chemical reaction, are expected from storage vessels, equipment leaks and the production line. The MACT standards also contain requirements t hat restrict the amount of HAP that can be used as an auxiliary blowing agent (ABA) . E missions of methylene chloride, the primary H AP ABA used, would be expected from storage vessels, equipment leaks, and the production line. However, since the compliance date of the MACT standards, all operating slabstock foam production facilities in the U.S. ha ve stopped using methylene chloride a s an ABA, and none currently use any HAP as an ABA.

3 .0 Approach to Estimating Risks from MACT

- allowable Emission Levels

The approach to estimate the risks from MACT

- allowable emission levels was to first estimate the relationship between the actual and MACT

- allowable emission levels, and then to estimate the potential risk impacts from the differences between actual and MACT

- allowable emissions. In general, the risk impact was assumed to be proportional to the difference in emission levels. For example, if MACT

- allowable emissions were estimated to be three times as high as actual emissions, it was assumed that risks could be as much as three times as high as those estimated from the modeling conducted using actual emissions. The assumption regarding the linear relationship between emissions and risks is generally reasonable for chronic cancer and noncancer risks. However, using this approach for acute risks would likely overestimate the impacts, as the acute risk estimate already has numerous built in c onservative assumptions.

T his general approach is valid where HAP emissions are present in the actual emissions

- level data used in the risk modeling and only differences in the proportion of HAP emitted exist; however, this approach is not appropriate where HAP in the actual emissions

- level data are entirely missing. As explained in Section 2 .0 of this document, the industry has stopped using HAP as auxiliary blowing agents (ABAs) in slabstock foam production, but the M ACT standards allow the use of HAP as ABAs in the production of this foam . As there are no HAP ABA s in the current actual emissions

- level data used for risk modeling, additional modeling was required to determine the risks that would be present at the MACT

- allowable level of HAP ABA use. For the facilities that produce slabstock foam, HAP ABA emissions were estimated for each facility based on emissions information gathered during development of the MACT standards. These emissions were then assigned approp riate emissions release parameters for each facility and modeled using the same modeling procedures and tools as that used for modeling with actual emissions . The product of this is an estimate of cancer risk s, chronic

non

- cancer risks and acute exposure risks associated with HAP ABA emissions at the MACT

allowable level for slabstock foam production facilities

.

4 .0 Results of Analysis

Equipment Cleaning and Mold Release Agents The ability to estimate MACT

- allowable emissions for specific emission points, or for specific emission point types, is largely dependent o n the format of the standards. For emission source types which have prohibitions on the use of HAP, including the use of HAP in equipment cleaning and the use of HAP as a mold release agent, there would be no difference between actual and MACT

allowable emissions, provided the facilit ies are complying with the rule. We have no information to4 suggest facilities are not complying with the MACT standards for these emission source types ; therefore, we believe the actual emissions levels are equal to the allowable emissions levels for these emission source types

. As these are the only regulated emissions source types at molded and rebond foam facilities, we believe actual emissions are equal to the allowable emissions levels for these facility types.

Storage Vessels and Equipment Leaks For slabstock foam facilities, there are work practices and equipmen t standards for storage vessels containing diisocyanates and HAP ABA. There are also work practices and equipment standards for diisocyanate equipment leaks and work practices for HAP ABA equipment leaks, with an option to use specified equipment rather th an perform the work practice s for pumps in HAP ABA service. For work practice standards and equipment standards

, there would be no difference between actual and MACT

- allowable emissions for emission sources, provided th e facilit ies are not conducting addi tional work practices

, are not using equipment proven to reduce emissions beyond those required in the rule

, and the equipment is maintained properly and is in good working condition (as required)

. For diisocyanate storage vessels and equipment leaks, w e are not aware of any situations where additional work practices or equipment are used or are not properly maintained at the facilit ies in th is source categor y . Therefore, for these storage vessels and equipment leaks, we believe that the actual emission levels are a reasonable estimation of the levels allowed by the MACT standard s

. We have learned that facilities in this source category have stopped using HAP ABAs, and therefore

, are no longer storing these materials or hav ing equipment leaks of HAP ABA

. Consequently, the amount of emissions allowed by the MACT standards is higher than the actual amount emitted. An estimate of the MACT

- allowable amount of HAP A BA emissions is discussed further below, in the context of the total HAP ABA emissions at slab stock FPUF p r o d u c t i o n facilities.

Slabstock Foam Production Lines For the foam production line at slabstock FPUF p r o d u c t i o n facilities, the MACT standards include HAP ABA formulation limits that restrict the amount of HAP ABA that can be used, depending on the grade and amount of each grade of foam produced. For each grade of foam produced, HAP ABAs could be emitted o n a spectrum based on the amount of HAP ABA actually used. Facilities could be using the maximum amount of HAP ABA allowed by the standards , less than the maximum amount of HAP ABA allowed, due to use of substitute non

- HAP ABAs or other types of processes that do not require as much ABA, or zero HAP ABA if a facility chooses to use only non

- HAP ABAs or processes that do not require the use of ABAs. We have determined through contact with industry representatives, that no facilities in the slabstock foam industry in the U.S. currently use HAP ABAs. Therefore, the MACT standards allow the use of HAP ABAs, but actual emissions of HAP ABAs are currentl y zero. Since facilities have stopped using HAP as ABAs, they are no longer storing these chemicals or using them in process equipment. Therefore, there are also currently no HAP ABA emissions from storage vessels or equipment leaks.

While we do not h ave information on the grades of foam produced at each facility or the amounts of HAP ABA that could be used at each, we have developed an estimate of the HAP ABA emissions for
a gene ral facility based on data used during development of the MACT standards. To determine costs and environmental impacts of regulatory alternatives, during the FPUF P r o d u c t i o n MACT standards development, five model plants were developed based on available information, including company responses to information collection requests, site vi sit observations, and information received from industry trade group associations, vendors, and company representatives. The estimates of HAP ABA5 emissions before implementation of the MACT standards for these model plants were based on the number and siz e of HAP ABA storage vessels, the number of components in HAP ABA service, the number of foam production lines, production line speed, and amounts of various grades of foam produced. Assuming that the HAP ABA chemical was also used to clean equipment, HAP ABA emissions were estimated for the model plants as shown in Table 3. As a result of the implementation of the MACT standards, the EPA estimated HAP ABA emissions would be reduced by 69%. a The estimated HAP ABA emissions remaining after MACT implementat ion are also shown in Table 3.

Table 3. Model Plant HAP ABA Emission s Estimates 1

Model Plant Total Estimated HAP ABA Emissions (TPY) Pre

- MACT HAP ABA Storage Emissions (TPY) Pre

- MACT HAP ABA Production Line Emissions (TPY) Pre

- MACT HAP ABA Equipment Cleaning Emissions (TPY) Pre

- MACT HAP ABA Equipment Leaks Emissions (TPY) Pre

MACT Post

MACT 1 64 20 0.09 55 5 3.5 2 174 64 0.26 165 5 3.5 3 339 105 0.52 330 5 3.5 4 343 106 0.03 335 5 3.5 5 388 120 0.03 380 5 3.5

1 “Hazardous Air Pollutant Emissions from the Production of Flexible Polyurethane Foam. Basis and Purpose Document for Proposed Standards.” Table s 7

- 1 and 8

- 2 . U.S. EPA Office of Air Quality Planning and Standards. September 1996.

The estimated post

- MACT implementation HAP ABA emissions range from 20 tons per year (TPY) per facility to 120 TPY per facility. We assume these are the levels of HAP ABA emissions typical facilities of various sizes and foam production volumes would emit at the MACT

- allowable level. As

we do not have data regarding current production volumes and grades of foam produced, it is not possible to determine which model facility represent s the currently operating slabstock foam production facilities . Therefore

, we have assumed the median model, Model Plant 3

, approximates the typical slabstock production facility and is likely representative of the currently operating slabstock production facilities . As such, we estimate that the MACT

- allowable HAP ABA emission s at slabstock production facilities are 105 TPY per facility, whereas actual HAP ABA emissions are 0 TPY for each of these facilit ies

.

To estimate r isks considering MACT

- allowable emissions at slabstock foam production facilities, we developed risk mode ling inputs for HAP ABA. As methylene chloride was the most commonly used HAP ABA a , we assumed that all HAP ABA was methylene chloride. We also assumed there was one fugitive release point of methylene chloride, to account for emissions from equipment le aks, storage vessels and equipment cleaning; and one point source emissions release point, to account for methylene chloride emissions from a foam production line roof stack

. The fugitive emissions release point was assumed to be 3% of the total HAP ABA em issions, or 3 TPY of methylene chloride, based on the pre

- MACT HAP ABA emissions from storage vessels, equipment leaks and equipment cleaning totaling 9 TPY

, reduced to 3 TPY with MACT controls. The point source emissions release

a Hazardous Air Pollutant Emissions from the Production of Flexible Polyurethane Foam. Basis and Purpose Document for Proposed Standards.” Page 6

- 9. U.S. EPA Office of Air Quality Plannin g and Standards. September 1996

.6 point was assumed to have 97% of the total HAP ABA emissions, or 102 TPY of methylene chloride, based on the pre

- MACT HAP ABA emissions from the foam production line of 330 TPY reduced to 102 TPY with MACT controls. The model emissions release point parameters and locations were based on other FPUF production emission point parameters and locations at each slabstock production facility. The emissions and emission point parameters used for modeling the MACT

- allowable HAP ABA emissions are included in the Appendix to this document.

In summary, t he MACT

- actual to MACT

- allowable emissions levels relationship for each FPUF regulated emissions source type is shown in Table 4. The estimated risks based on the MACT

allowabl e emissions is shown in Table 5.

Table 4. PFUF Emission Source Type MACT

- Actual to MACT

- Allowable Emissions Summary

FPUF Production Subcategory Emission Source Type Actual to Allowable Emissions Relationship Slabstock Storage Vessels

- Diisocyanates Ac tual = Allowable Equipment Leaks

- Diisocyanates Storage Vessels

– HAP ABA

Actual < Allowable; Allowable Emissions Estimated from Model Plant Information Equipment Leaks

– HAP ABA Production Line

– HAP ABA Equipment Cleaning

– HAP ABA Source

- wide emission limit alternative Molded Equipment Cleaning

Actual = Allowable Mold Release Agents Rebond Equipment Cleaning Mold Release Agents

Table 5

. Summary of Estimated Inhalation Risks for FPUF Pr oduction Based On MACT

Allowable Emissions Levels Actual MACT

- Allowable

Source Category Maximum individual

cancer risk (in a million) Maximum chronic

noncancer TOSHI Maximum acute HQ Maximum individual

cancer risk (in a million) Maximum chronic

noncancer TOSHI Maximum acute HQ

FPUF Production 0.7 0.9 0.9 5 0.9 4

### DRAFT

– DO NOT QUOTE OR CITE

A

- 1 Appendix

MACT

- allowable HAP ABA Emissions and Emission Point Parameters

FACILITY NAME CITY STATE EMISSION UNIT ID POLLUTANT
DESCRIPTION EMISSIONS (TPY) STACK
HEIGHT

(FT) EXIT GAS
TEMPERA TURE (F) STACK
DIAMETE

R (FT) EXIT GAS
VELOCITY

(FT/S) FUGITIVE
LENGTH

(FT) FUGITIVE
WIDTH

(FT) FUGITIVE
ANGLE
DEGREES LONGITUDE
COORDINATE LATITUDE
COORDINATE
PREMIER FOAM INC. NEWNAN GA HAP ABA allowable fugitive emissions Methylene Chloride 3 10 72 0.003 0.0003 50 65 0 -84.792813 33.345083
PREMIER FOAM INC. NEWNAN GA HAP ABA allowable point emissions Methylene Chloride 102 35.69408 168.7812 1.941379 30.57371 -84.792813 33.345083 FOAMEX, L.P. FT. WAYNE IN HAP ABA allowable fugitive emissions Methylene Chloride 3 10 72 0.003 0.0003 45 75 92 -85.176306 41.007313 FOAMEX, L.P. FT. WAYNE IN HAP ABA allowable point emissions Methylene Chloride 102 23 80 3.7 22 -85.17694 41.007287
FOAMEX L.P. AUBURN IN HAP ABA allowable fugitive emissions Methylene Chloride 3 11 72 0.003 0.0003 50 65 73 -85.064972 41.349025
FOAMEX L.P. AUBURN IN HAP ABA allowable point emissions Methylene Chloride 102 28 94 8.9 5 -85.064693 41.349533
Flexible Foam Products Inc Tupelo MS HAP ABA allowable fugitive emissions Methylene Chloride 3 10 72 0.003 0.0003 50 65 0 -88.685946 34.230915
Flexible Foam Products Inc Tupelo MS HAP ABA allowable point emissions Methylene Chloride 102 40 86 4 79.6 -88.685946 34.230915 Hickory Springs Manufacturing Conover NC HAP ABA allowable fugitive emissions Methylene Chloride 3 10 72 0.003 0.0003 50 65 0 -81.241851 35.71747 Hickory Springs Manufacturing Conover NC HAP ABA allowable point emissions Methylene Chloride 102 95 77 3.5 27.6 -81.241851 35.71747 Foamex International, Inc. Cornelius NC HAP ABA allowable fugitive emissions Methylene Chloride 3 10.75 72 0.003 0.0003 37 105 325 -80.849265 35.465719 Foamex International, Inc. Cornelius NC HAP ABA allowable point emissions Methylene Chloride 102 75 100 1 135 -80.849875 35.466756 FOAMEX LP/CORRY CORRY PA HAP ABA allowable fugitive emissions Methylene Chloride 3 30 72 0.003 0.0003 50 65 0 -79.616216 41.916883 FOAMEX LP/CORRY CORRY PA HAP ABA allowable point emissions Methylene Chloride 102 30 70 3 20 -79.614119 41.916276