MEMORANDUM

Date: January 8, 2014

Subject: Revised MACT-Allowable Emissions and Risks for the Pesticide Active Ingredient 

Production, Polyether Polyols Production, and Group IV Polymers and Resins Source 

Categories

From: Lesley Stobert, EC/R Incorporated

To: Nick Parsons, EPA/OAQPS/SPPD

_________________________________________________________________________________

The purpose of this memorandum is to present analyses related to “MACT-allowable” 

emissions levels and risks for the Pesticide Active Ingredient Production (PAI), Polyether Polyols 

Production (PEPO), and Group IV Polymers and Resins (P&R IV) source categories that are being 

addressed under EPA’s residual risk and technology review (RTR) program. This is a revision to a 

previous memo developed for the proposed rulemaking for these source categories to consider the 

revised emissions data that was received during the comment period and the revised estimates of risks 

based on these data. 

The RTR program is addressing 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. They are commonly referred to 

as Maximum Achievable Control Technology (MACT) standards. The emissions data being used for 

the RTR risk assessments for these categories consist of data representative of “actual” emission 

levels. In addition to the risks associated with these actual emission levels, EPA also considers the 

levels of HAP emissions that sources 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 memorandum 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 each source category, and Section 2 discusses the basic 

approach to estimating the risks from the MACT-allowable levels. This is followed by a discussion of 

the estimation of the MACT-allowable emission level for each MACT standard in Section 3, 

particularly as it relates to the actual emission levels used in the risk assessments. This discussion is 

followed by a presentation of the estimated risks at these MACT-allowable levels.

1.0 Risk Levels Based on Actual Emissions

The estimated maximum inhalation risks for these source categories are summarized in 

Table 1. These risks are based on actual emission levels.
2

Table 1. Summary of Estimated Inhalation Risks for the PAI, PEPO, and P&R IV Source 

Categories Based On Actual Emissions Levels

Source Category

Maximum individual 

cancer risk (in a 

million)1

Maximum chronic 

noncancer TOSHI2

Pesticide Active Ingredient (PAI) Production 6 0.7

Polyether Polyols (PEPO) Production 30 0.7

Group IV Polymers and Resins3

 Acrylic-Butadiene-Styrene (ABS) Production 20 0.3

 Methyl Methacrylate-Butadiene-Styrene (MBS) Production 1 0.02

 Polyethylene Terephthalate (PET) Production 10 0.4

 Polystyrene Production (PS) 0.08 0.006

 Styrene-Acrylonitrile (SAN) Production 0.4 0.003

1 Maximum individual excess lifetime cancer risk.

2 Maximum target organ specific hazard index (TOSHI). Target organ system represented by the TOSHI varies across 

source categories. Maximum TOSHI is based on respiratory effects for the PAI, PEPO, PET, and SAN, neurological 

effects for PS, the spleen for ABS, and reproductive effects for MBS. 

3 Two additional source categories are regulated by the P&R IV MACT standards no longer have any operating facilities 

in the U.S., and none are anticipated to begin operation in the future. For these source categories, Methyl MethacrylateAcrylonitrile-Butadiene-Styrene Production and Nitrile Resins Production, risks were not estimated.

2.0 Approach to Estimating Risks from MACT-Allowable Emission Levels

Detailed MACT-allowable emissions information is not available on an emission pointspecific level. Therefore, modeling was not conducted to estimate the risks from MACT-allowable 

emission levels.

The basic 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 
3

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.

This 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. The acute assessment already has numerous built in 

conservative assumptions. First, the acute assessment assumed a short-term emission rate up to 

10 times that of the average longer term emission rate. Also, the maximum acute risks assume the 

simultaneous occurrence of independent factors that may vary greatly, such as hourly emissions rates, 

meteorology, and human activity patterns. In the assessment using actual emissions, EPA assumed 

that individuals remained for 1 hour at the point of maximum ambient concentration as determined by 

the co-occurrence of peak emissions and worst-case meteorological conditions. These assumptions 

would tend to overestimate actual exposures since it is unlikely that a person would be located at the 

point of maximum exposure during the time of worst-case impact. The addition of another factor to 

account for the MACT-allowable emissions level would further increase the conservativeness of the 

estimated MACT-allowable acute risks. Therefore, this analysis does not discuss acute risks or 

estimate acute risks for the MACT-allowable emissions level.

3.0 Results of Analysis

a. Group IV Polymers and Resins Source Categories

The Group IV Polymers and Resins NESHAP addresses emissions from the following types of 

emission sources for all five source categories: (1) storage tanks, (2) continuous process vents, (3) 

batch process vents, (4) equipment leaks, (5) wastewater, and (6) heat exchange systems. Table 2 

summarizes the formats of the standards for these emission points.

Table 2. Formats of Standards for the Group IV Polymers and Resins NESHAP

Emission Source Type Format of Primary Standard

Storage Tanks Equipment Standards

Continuous Process Vents Performance Standard (% reduction)a

Batch Process Vents Performance Standard (% reduction)

Equipment Leaks Work Practice Standards

Wastewater Equipment Standards, Performance Standard

Heat Exchange Systems Work Practice Standards

a The NESHAP contains an alternative standard for some source categories or subcategories to reduce emissions on a kg 

emissions/Mg product basis

The ability to estimate MACT-allowable emissions for specific emission points, or for specific 

emission point types, is largely dependent on the format of the standards. For equipment standards, 

sources subject to the regulation are required to install specific equipment. Assuming that the 

equipment is maintained properly and is in good working condition (as required), there would not be a 

difference in the actual emissions level and the level allowed by the standard. Similarly, there would 

be no difference between actual and MACT-allowable emissions for emission sources subject to work 

practice requirements, provided that facilities are not conducting additional work practices proven to 

reduce emissions beyond those required in the rule. We are not aware of any such situations at 

facilities in these five Group IV Polymers and Resins source categories. Therefore, for equipment 
4

leaks, storage vessels, heat exchange systems, and process contact cooling towers, which are subject 

to equipment and work practice standards, we believe that the actual emission levels are a reasonable 

estimation of the levels allowed by the standard.

For wastewater emission sources, the regulation includes an assortment of equipment and 

performance standards. As discussed above, it is reasonable to assume that the actual emissions from 

those sources subject to equipment standards are representative of the MACT-allowable emissions. In 

general, it is possible that sources could overcontrol emission sources subject to a performance 

standard. This would result in the actual emissions being lower than the MACT-allowable emissions. 

However, for wastewater sources, we are not aware of any such overcontrol. Therefore, we believe 

that the actual wastewater emission levels are a reasonable estimation of the levels allowed by the 

standard.

For continuous and batch process vents, which are subject to performance standards, we 

believe that there may be situations where sources are utilizing control devices that achieve reductions 

greater than the required percent reduction (i.e., 98% for continuous process vents and generally 90% 

for batch process vents). However, for continuous process vents, the continuous monitoring 

requirements of the rule result in situations where reductions greater than these percent reductions are 

required on a continuous basis. Specifically, owners and operators are required to conduct 

performance tests to demonstrate initial compliance. During the test, they are required to monitor a 

specific parameter (e.g., temperature for a thermal incinerator). From the data collected during the 

test, they are required to calculate a parameter level (e.g., a minimum temperature) that is indicative 

of the control device performance achieved during the test. Ongoing compliance is then determined 

based on the monitoring of this parameter as compared to the established level (e.g., if the incinerator 

temperature falls below the minimum temperature established during the test it would be an 

excursion). Therefore, if an incinerator was achieving a 99 percent emission reduction during the 

performance test, the temperature level established based on monitoring data collected during the test 

would be reflective of a 99 percent reduction. Thus, the performance level required by the rule would, 

in effect, be 99 percent. Because of these requirements, we assume that the actual emission levels are

a reasonable estimation of MACT-allowable emissions for continuous process vents.

For batch process vents, similarly to continuous process vents, owners and operators are 

required to conduct performance tests of control devices to demonstrate the control efficiency of the 

device and identify the parameter level that corresponds with the required emissions reduction 

efficiency. This parameter must then be monitored during batch events and be within the established 

range to demonstrate compliance. While it is possible that the demonstrated control efficiency is 

above the 90% reduction requirement of the standard, the standard also allows for the 90% reduction 

to be achieved by controlling only selected batch emission episodes or portions of selected batch 

emission episodes to achieve an overall reduction of 90%. If a source controls all portions of all batch 

emission episodes to a level above 90%, the actual emissions for that source would be less than the 

allowable emissions. However, we are not aware of any such overcontrol. Therefore, we believe that 

the actual batch process vent emission levels are a reasonable estimation of the levels allowed by the 

standard.

Facilities producing polystyrene using a continuous process, PET using a continuous dimethyl 

terephthalate, or PET using a continuous terephthalic acid process may choose to comply with an 

emission limitation based on production, rather than a 98% percent reduction requirement. These 
5

limits were put into place based on the use of condensers and other recovery technologies in the 

industry as an alternative to the percent reduction requirements applicable to combustion equipment. 

This alternate standard format was selected because for this technology, HAP are reduced to a 

specific level, dependent on the vaporization and condensation properties of the HAP, but the 

technology is not particularly sensitive to the initial HAP concentration in the uncontrolled gas

stream. Facilities in these source categories generally are complying with the rule requirements using 

these recovery technologies, and are not known to be using any versions of these technologies that 

achieve better performance than required to meet the emission limits. Therefore, for the facilities in 

these source categories, we estimate the actual emissions are equal to the MACT-allowable emissions. 

In addition, for the primary HAP used and emitted by facilities in these source categories, recovery 

technologies should be capable of reducing HAP to 98% or more. Therefore, if any facilities are 

actually using combustion control rather than recovery technology, emissions would be 

approximately the same and would be equal to the MACT-allowable level for either compliance 

format.

In summary, the risks based on the “MACT-allowable” emissions levels are shown in Table 6 

and are equal to the risks at the actual emissions levels for the Group IV Polymers and Resins 

NESHAP.

b. Polyether Polyols Production

The Polyether Polyols Production NESHAP addresses emissions from the following types of 

emission sources: (1) storage tanks, (2) continuous process vents, (3) batch process vents, (4) 

equipment leaks, (5) wastewater, and (6) heat exchange systems. Table 3 summarizes the formats of 

the standards for these emission points.

Table 3. Formats of Standards for the Polyether Polyols Production NESHAP

Emission Source Type Format of Primary Standard

Storage Tanks Equipment Standards

Process Vents Performance Standard (% reduction)a

Equipment Leaks Work Practice Standards

Wastewater Equipment Standards, Performance Standard

Heat Exchange Systems Work Practice Standards

a The NESHAP contains an alternative standard to reduce emissions on a kg emissions/Mg product basis

As in the P&R IV MACT standards, for equipment leaks, storage vessels, and heat exchange 

systems, which are subject to equipment and work practice standards, we believe that the actual 

emission levels are a reasonable estimation of the levels allowed by the standard. We also believe that 

the actual emission levels are a reasonable estimation of the levels allowed by the standard for 

wastewater emission sources, which are regulated by equipment and performance standards.

For process vents, all HAP associated with units producing polyether polyols using 

tetrahydrofuran are required to be reduced by 98%. For existing units producing polyther polyol 

products using epoxides, all epoxide HAP are required to be reduced by 98%, while non-epoxide 

organic HAP are required to be reduced by 98% for continuous process vents and by 90% for batch 

process vents and process vents that use organic HAP in catalyst extraction. It is possible that some of 

the process vents that are only required to achieve 90% emissions reduction in non-epoxide organic 
6

HAP actually achieve 98% emissions reduction. In these cases, 10% of non-epoxide organic HAP 

would be emitted at the MACT-allowable level, and it is possible that facilities are actually only 

emitting 2% (i.e., 98% emissions reduction). The maximum ratio of MACT-allowable to actual 

emissions is therefore 10/2 = 5. Because it was not possible to determine whether an emissions point 

was a process vent or other type of emissions source or whether any point was associated with a 

certain type of polyether polyol unit in the NEI, this ratio of 5 was applied to all non-epoxide organic 

HAP emissions associated with point (rather than fugitive) sources to be conservative. The MIR based 

on actual emissions is 30, which is caused predominantly by ethylene oxide (an epoxide) emissions. 

The application of this factor to non-epoxide organic emissions does not increase risk for any 

emissions receptors beyond this level. In addition, the maximum TOSHI based on actual emissions is 

0.7, which is based predominantly on emissions of acrolein from fugitive sources. The application of 

this factor to non-epoxide organic emissions from point sources does not increase risk for any 

receptors beyond this level. Therefore, even though the non-epoxide HAP MACT-allowable 

emissions are five times higher than the actual emissions, there is no appreciable difference in the 

MACT-allowable risk levels.

Facilities producing polyether polyol products using epoxides may choose to comply with an 

epoxide emission limitation based on production, rather than a percent reduction requirement. These 

limits were put into place to allow facilities to take credit for reacting their product to completion in 

an extended cookout process, which reduces emissions of ethylene oxide and propylene oxide. 

However, during MACT development, industry commented that the emission factor format based on 

the lowest emissions per production would restrict facilities from making certain polyols classes that 

have higher emissions of epoxides. To allow for a variety of polyether polyol products to be made, the 

percent reduction format was chosen as the MACT standard with the alternative of meeting the 

emission factor limit. Facilities with units that make polyols classes with higher emissions of epoxides 

most of the time will likely comply with the percent reduction limit for those units because it would 

not be possible to comply with the emission factor format. For these units, we believe that there may 

be situations where sources are utilizing control devices that achieve reductions greater than the 

required percent reduction (i.e., 98% for existing process vents). However, as with P&R IV 

continuous process vents, the monitoring requirements of the rule result in situations where reductions 

greater than these percent reductions are required because parameters are monitored based on an 

established level which is reflective of actual operating conditions. Because of these requirements, we 

assume that the actual emission levels are a reasonable estimation of MACT-allowable emissions for 

these process vents.

Polyether polyol units that make polyols classes with lower epoxide emissions may comply 

with the emission factor format. The MACT standard in this format is 0.019 kg epoxide emissions per 

Megagram of product made for all process vents from the unit for existing sources, determined on an 

annual basis. In general, it is possible that units could emit at levels lower than this standard, which 

would result in the actual emissions being lower than the MACT-allowable emissions. Epoxide 

emissions vary depending upon the polyether polyol product made, and we are not aware of any such 

routine overcontrol that would cause emissions to be substantially lower. However, to investigate this 

situation further, we compared actual reported emissions in the NEI to the emissions that would be 

expected if facilities emit at the standard level and operate at capacity. Using information from 

MACT development to estimate the number of small, medium, and large facilities based on capacity 

and the average capacities for those sized facilities, we determined the average emissions that would 

be expected if all facilities emitted epoxide emissions at the level of the standard in the emissions 
7

factor format. The resulting total epoxide emissions from process vents for the source category is 

estimated to be 22 tons per year (TPY). This information is shown in Table 4. This total process vents 

epoxide emissions value was compared to the total epoxide emissions that may be attributed to 

process vents in the NEI data, which was determined based on the source category code (SCC) and 

the point source emission release type. In the NEI data this value is approximately 38 TPY. The 

emissions contributing to this value are shown in the Appendix to this document. Using these 

assumptions, emissions from process vents are less when using the emission factor than the reported 

actual emissions. Therefore, we do not have reason to believe that facilities are using this emission 

factor standard format and achieving emissions reduction beyond that required by the standard, and 

we assume that the actual emission levels are a reasonable estimation of MACT-allowable emissions 

for these process vents.

Table 4. Epoxide Emissions at Average Capacity for PEPO Facilities Complying with the 

Emission Factor Standard Format

Total 

Number 

of 

Facilities

Facility 

Size

Percent 

of Total 

Facilities 

at 

Facility 

Size

Number 

of 

Facilities 

at 

Facility 

Size

Average 

Capacity 

Mg/yr

Average 

Capacity 

Utilization 

%

Average 

Utilized 

Capacity

(Mg/yr)

Epoxide 

Emissions 

(TPY) 

Per 

Facility 

at 

Utilized 

Capacity 

with 0.19 

kg/Mg 

Emitted

Epoxide 

Emissions 

(TPY) 

Per 

source 

Category 

Size 

Segment

Total 

Epoxide 

Emissions 

(TPY) for 

Source 

Category

23

Small 30 7 27,488 87.95 21,175 0.51 3.94

Medium 21 5 43,635 82.59 36,038 0.75 3.64 29.26

Large 49 11 129,001 72.86 93,990 1.96 22.14

In summary, the risks based on the “MACT-allowable” emissions levels are shown in Table 6 

and are equal to the risks at the actual emissions levels for the Polyether Polyols NESHAP.

c. Pesticide Active Ingredient Production

The Pesticide Active Ingredient Production NESHAP addresses emissions from the following 

types of emission sources: (1) storage tanks, (2) process vents, (3) equipment leaks, (4) wastewater, 

(5) bag dumps and product dryers, and (6) heat exchange systems. Table 5 summarizes the formats of 

the standards for these emission points.

Table 5. Formats of Standards for the Pesticide Active Ingredient Production NESHAP

Emission Source Type Format of Primary Standard

Storage Tanks Equipment Standards

Continuous Process Vents Performance Standard (% reduction)

Equipment Leaks Work Practice Standards

Wastewater Equipment Standards, Performance Standard

Bag Dumps and Product Dryers Emission Limit (concentration limit)

Heat Exchange Systems Work Practice Standards
8

As in the P&R IV and PEPO MACT standards, for equipment leaks, storage vessels, and heat 

exchange systems, which are subject to equipment and work practice standards, we believe that the 

actual emission levels are a reasonable estimation of the levels allowed by the standard. We also 

believe that the actual emission levels are a reasonable estimation of the levels allowed by the 

standard for wastewater emission sources, which are regulated by equipment and performance 

standards. For bag dumps and product dryers, particulate matter from these sources is controlled with 

fabric filters. As the level of the standard, 0.01 grains per dry standard cubic foot (gr/dscf), is typical 

of the level of control achieved by fabric filters, we believe the actual emissions level using this 

equipment is a reasonable estimation of the level allowed by the standard.

For process vents, the standard requires 98% emission reduction of organic HAP for process 

vents with control devices installed after November 10, 1997 (the proposal date of the standard) and 

90% control for process vents with controls installed on or before that date. It is possible that some of 

the process vents that are only required to achieve the 90% emissions reduction actually achieve 98% 

emissions reduction. In these cases, 10% of organic HAP would be emitted at the MACT-allowable 

level, and it is possible that facilities are actually only emitting 2% (i.e., 98% emissions reduction). 

The maximum ratio of MACT-allowable to actual emissions is therefore 10/2 = 5. Because it was not 

possible to determine whether an emission point was a process vent or other type of emissions source 

in the NEI, this ratio of 5 was applied to all organic HAP emissions associated with point (rather than 

fugitive) sources to be conservative. The MIR based on actual emissions is 6, which is caused entirely 

by fugitive emission points, and the maximum TOSHI is 0.7, which is caused entirely by non-organic 

HAP emissions. The application of the factor of 5 to point source organic HAP emissions results in an 

MIR of 7 and a TOSHI of 0.8.

For halogenated process vents, the standard requires 94% reduction in HCl and Cl2 emissions 

if uncontrolled emissions for all process vents within a process exceed 6.8 Mg/yr HCl and Cl2 

emissions. From information gathered during development of the MACT, many process vent totals 

exceeded this threshold.1It is possible to achieve 99% or greater emissions reduction with equipment 

commonly used in the chemical manufacturing industry, and such reduction is required by other 

NESHAP, including the Hazardous Organic NESHAP (HON), P&R IV, and others. It is possible that 

some of the process vents that are only required to achieve 94% emissions reduction actually achieve 

99% emissions reduction of HCl and Cl2 emissions. In these cases, 6% of these HAP would be 

emitted at the MACT-allowable level, and it is possible that facilities are actually only emitting 1% 

(i.e., 99% emissions reduction). The maximum ratio of MACT-allowable to actual emissions is 

therefore 6/1 = 6. Because it was not possible to determine whether an emission point was a process 

vent or other type of emissions source in the NEI, this ratio of 6 was applied to all HCl and chlorine 

emissions associated with point sources, to be conservative. The maximum TOSHI is 0.7, which is 

caused entirely by non-organic HAP emissions from a combination of fugitive and point source 

emissions points. The application of the factor of 6 to the HCl and chlorine emissions from point 

sources results in a MACT-allowable TOSHI of 4. 

The resulting risks based on the application of the organic HAP ratio of 5 and the HCl and Cl2 

emissions ratio of 6 are shown in the “MACT-allowable” level risks shown in Table 6.

 

1

1 Basis and Purpose Document for the Pesticide Active Ingredient Production NESHAP. U.S. EPA. July 1997.
9

Table 6. Summary of Estimated Inhalation Risks for the PAI, PEPO, and P&R IV Source 

Categories Based On MACT-Allowable Emissions Levels

Actual MACT-Allowable

Source Category

Maximum 

individual 

cancer risk (in a 

million)

Maximum 

chronic 

noncancer 

TOSHI

Maximum 

individual 

cancer risk (in a 

million)

Maximum 

chronic 

noncancer 

TOSHI

Pesticide Active Ingredient Production 6 0.7 7 4

Polyether Polyols Production 30 0.7 30 0.7

Group IV Polymers and Resins

 Acrylic-Butadiene-Styrene (ABS) 

Production 20 0.3 20 0.3

 Methyl Methacrylate-ButadieneStyrene (MBS) Production 1 0.02 1 0.02

 Polyethylene Terephthalate (PET) 

Production 10 0.4 10 0.4

 Polystyrene Production (PS) 0.08 0.006 0.08 0.006

 Styrene-Acrylonitrile (SAN) 

Production 0.4 0.003 0.4 0.003
Appendix

Polyether Polyols Production Epoxide Emissions Associated with 

Process Vents in the NEI
A-1

NTI_SITE_ID FACILITY_NAME CITY STATE SCC SCC1 SCC2 SCC3 SCC4 HAP_CATEGORY_NAME EMISSIONS_TPY EMISSION_RELEASE_POINT_TYPE_DESC

NEI7491 HOUSTON PLANT HOUSTON T X 30100999 Industrial Processes Chemical Manufacturing Cleaning Chemicals Other Not Classified Ethylene Oxide 0.115999997 VERTICAL

NEI7491 HOUSTON PLANT HOUSTON T X 30100999 Industrial Processes Chemical Manufacturing Cleaning Chemicals Other Not Classified Ethylene Oxide 0.0003 VERTICAL

NEI7491 HOUSTON PLANT HOUSTON T X 30100999 Industrial Processes Chemical Manufacturing Cleaning Chemicals Other Not Classified Propylene Oxide 0.0093 VERTICAL

NEI7491 HOUSTON PLANT HOUSTON T X 30100999 Industrial Processes Chemical Manufacturing Cleaning Chemicals Other Not Classified Propylene Oxide 0.0002 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30101101 Industrial Processes Chemical Manufacturing Hydrochloric Acid By-product Process Ethylene Oxide 0.001 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30101870 Industrial Processes Chemical Manufacturing Plastics Production Reactor (Polyether Resins) Ethylene Oxide 0.0011 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30101870 Industrial Processes Chemical Manufacturing Plastics Production Reactor (Polyether Resins) Propylene Oxide 0.0011 VERTICAL

NEI6155 RUBICON, LLC GEISMAR L A 30101885 Industrial Processes Chemical Manufacturing Plastics Production Other Not Classified (Polyurethane) Ethylene Oxide 0.0015 VERTICAL

NEI6155 RUBICON, LLC GEISMAR L A 30101885 Industrial Processes Chemical Manufacturing Plastics Production Other Not Classified (Polyurethane) Propylene Oxide 0.0365 VERTICAL

NEINC0595 Emerald Carolina Chemical, LLC Charlotte N C 30101899 Industrial Processes Chemical Manufacturing Plastics Production Others Not Specified Ethylene Oxide 0.1968 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30103410 Industrial Processes Chemical Manufacturing Aniline/Ethanolamines General: Ethanolamines Ethylene Oxide 0.0005 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30113799 Industrial Processes Chemical Manufacturing Esters Production Acrylates: Specify in Comments Ethylene Oxide 0.453799993 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30113799 Industrial Processes Chemical Manufacturing Esters Production Acrylates: Specify in Comments Propylene Oxide 0.121399999 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.745000005 HORIZONTAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.0084 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.256199986 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.0003 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.119999997 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.200000003 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30117401 Industrial Processes Chemical Manufacturing Ethylene Oxide General Ethylene Oxide 0.1043 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30117421 Industrial Processes Chemical Manufacturing Ethylene Oxide Stripper Purge Vent Ethylene Oxide 0.129999995 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30117421 Industrial Processes Chemical Manufacturing Ethylene Oxide Stripper Purge Vent Ethylene Oxide 5.710000038 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30117421 Industrial Processes Chemical Manufacturing Ethylene Oxide Stripper Purge Vent Ethylene Oxide 1.379999995 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30119706 Industrial Processes Chemical Manufacturing Butylene, Ethylene, Propylene, Olefin Production Propylene: Reactor Propylene Oxide 0.153600007 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30120501 Industrial Processes Chemical Manufacturing Propylene Oxide General Propylene Oxide 0.0009 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30120501 Industrial Processes Chemical Manufacturing Propylene Oxide General Propylene Oxide 0.0013 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30120501 Industrial Processes Chemical Manufacturing Propylene Oxide General Propylene Oxide 0.0014 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30120545 Industrial Processes Chemical Manufacturing Propylene Oxide Light-ends Stripping Column Vent Propylene Oxide 0.0072 HORIZONTAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30125099 Industrial Processes Chemical Manufacturing Methanol/Alcohol Production Other Not Classified Ethylene Oxide 0.033 VERTICAL

NEI6032 BASF CORPORATION/GEISMAR SITE Geismer L A 30125099 Industrial Processes Chemical Manufacturing Methanol/Alcohol Production Other Not Classified Ethylene Oxide 0.116 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30125099 Industrial Processes Chemical Manufacturing Methanol/Alcohol Production Other Not Classified Ethylene Oxide 0.173500001 VERTICAL

NEI6032 BASF CORPORATION/GEISMAR SITE Geismer L A 30125099 Industrial Processes Chemical Manufacturing Methanol/Alcohol Production Other Not Classified Propylene Oxide 0.006 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30125099 Industrial Processes Chemical Manufacturing Methanol/Alcohol Production Other Not Classified Propylene Oxide 0.046999998 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 2.440000057 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.012 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.0069 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.038400002 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.023600001 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.023600001 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.0053 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.0167 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.038400002 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.043699998 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.0011 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Ethylene Oxide 0.0003 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.052200001 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.166600004 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.096699998 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.096699998 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.093699999 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.145400003 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.166600004 VERTICAL

NEI12066 HUNTSMAN PETROCHEMICAL CORP/CONROE FACILITY CONROE T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.022500001 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30125101 Industrial Processes Chemical Manufacturing Ethylene Glycol General Propylene Oxide 0.0014 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30125301 Industrial Processes Chemical Manufacturing Glycol Ethers General Ethylene Oxide 0.0055 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30125301 Industrial Processes Chemical Manufacturing Glycol Ethers General Ethylene Oxide 0.129999995 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30125301 Industrial Processes Chemical Manufacturing Glycol Ethers General Ethylene Oxide 0.017000001 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30125306 Industrial Processes Chemical Manufacturing Glycol Ethers Methanol Recovery Column Vent Ethylene Oxide 0.019300001 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30125326 Industrial Processes Chemical Manufacturing Glycol Ethers Butanol Recovery Column Vent Ethylene Oxide 0.072800003 VERTICAL
A-2

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30181001 Industrial Processes Chemical Manufacturing General Processes Air Oxidation Units Ethylene Oxide 0.0638 VERTICAL

NEI11295 DOW CHEMICAL CO FREEPORT FACILITY Freeport T X 30181001 Industrial Processes Chemical Manufacturing General Processes Air Oxidation Units Propylene Oxide 0.0101 VERTICAL

NEI8011 Dow Seadrift Plant SEADRIFT T X 30184001 Industrial Processes Chemical Manufacturing General Processes Distillation Units Ethylene Oxide 0.015900001 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30190023 Industrial Processes Chemical Manufacturing Fuel Fired Equipment Natural Gas: Flares Ethylene Oxide 0.1 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30190099 Industrial Processes Chemical Manufacturing Fuel Fired Equipment Specify in Comments Field Propylene Oxide 1.749500036 HORIZONTAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30190099 Industrial Processes Chemical Manufacturing Fuel Fired Equipment Specify in Comments Field Propylene Oxide 0.479999989 HORIZONTAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30190099 Industrial Processes Chemical Manufacturing Fuel Fired Equipment Specify in Comments Field Ethylene Oxide 0.001 VERTICAL

NEI7296 EASTMAN CHEMICAL CO TEXAS OPERATIONS LONGVIEW T X 30190099 Industrial Processes Chemical Manufacturing Fuel Fired Equipment Specify in Comments Field Ethylene Oxide 0.0028 VERTICAL

NEI44055 Cognis Corporation Charlotte N C 30199998 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.03278 VERTICAL

NEI44055 Cognis Corporation Charlotte N C 30199998 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.014625 VERTICAL

NEI11319 LYONDELL CHEMICAL CO - CHANNELVIEW PLANT CHANNELVIEW T X 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 4.825399876 HORIZONTAL

NEI11319 LYONDELL CHEMICAL CO - CHANNELVIEW PLANT CHANNELVIEW T X 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 3.238899946 HORIZONTAL

NEI11319 LYONDELL CHEMICAL CO - CHANNELVIEW PLANT CHANNELVIEW T X 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 2.324800014 HORIZONTAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.35374 VERTICAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.416 VERTICAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.239 VERTICAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.188 VERTICAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.229 VERTICAL

NEISCT$3391 MILLIKEN CHEMICAL DEWEY PLAN T INMAN SC 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.25 VERTICAL

NEIPA13-5603 CRODA INC/DRAKETOWN ROAD MILL HALL PA 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.430000007 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0005 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0145 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.011 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.011 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0025 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0015 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0005 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 1.1265 VERTICAL

NEILA13809 UNION CARBIDE CORP/TAFT/STAR MANUFACTURING COMPLEX HAHNVILLE L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.015 VERTICAL

NEI6032 BASF CORPORATION/GEISMAR SITE Geismer L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 1.782 VERTICAL

NEI6032 BASF CORPORATION/GEISMAR SITE Geismer L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.1585 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.933 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.002 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0735 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.031 VERTICAL

NEI6013 SHELL CHEMICAL LP/GEISMAR PLANT GEISMAR L A 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0665 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.02 VERTICAL

NEI12483 PORT NECHES OPERATIONS C4 PLANT PORT NECHES T X 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.02 VERTICAL

NEIWV0390005 INSTITUTE PLANT UNION CARBIDE CORP INSTITUTE WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 0.036 VERTICAL

NEISCT$3391 MILLIKEN CHEMICAL DEWEY PLAN T INMAN SC 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 0.11 VERTICAL

NEIPA13-5603 CRODA INC/DRAKETOWN ROAD MILL HALL PA 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 0.129999995 VERTICAL

NEI45600 UNION CARBIDE CORP SOUTH CHARLESTON PLANT SOUTH CHARLESTON WV 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Propylene Oxide 0.013 VERTICAL

NEI44055 Cognis Corporation Charlotte N C 30199999 Industrial Processes Chemical Manufacturing Other Not Classified Specify in Comments Field Ethylene Oxide 0.0022277 VERTICAL WITH RAIN CAP

NEIWV0138 BAYER CORP INSTITUTE WV 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Ethylene Oxide 0.0405 VERTICAL

NEI8432 HUNTSMAN PETROCHEMICAL CORP DAYTON T X 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Ethylene Oxide 0.4785 VERTICAL

NEI56265 STEPAN CO ELWOOD I L 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Ethylene Oxide 0.131 VERTICAL

NEI11906 THE DOW CHEMICAL COMPANY U.S.A., MIDLAND MIDLAND MI 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Ethylene Oxide 0 VERTICAL

NEIWV0138 BAYER CORP INSTITUTE WV 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Propylene Oxide 1.45 VERTICAL

NEI8432 HUNTSMAN PETROCHEMICAL CORP DAYTON T X 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Propylene Oxide 0.0935 VERTICAL

NEI56265 STEPAN CO ELWOOD I L 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Propylene Oxide 0.14 VERTICAL

NEI11906 THE DOW CHEMICAL COMPANY U.S.A., MIDLAND MIDLAND MI 39999999 Industrial Processes Miscellaneous Manufacturing Industries Miscellaneous Industrial Processes See Comment ** Propylene Oxide 1.795 VERTICAL

TOTAL 37.52457264