### MEMORANDUM

DATE : May 1 9 , 2014

SUBJECT: Risk Assessment to Determine a Health

- Based Emission Limitation for Acid

Gases for the Brick and Structural Clay Products Manufacturing Source Category

FROM: Mark Morris Health and Environmental Impacts Division Office of Air Quality Planning and Standards

Ted Palma Health and Environmental Impacts Division Office of Air Quality Planning and Standards

Chris Sarsony Health and Environmental Impacts Division Office of Air Quality Planning an d Standards

TO: Docket EPA

- HQ

- OAR

- 2013

- 0291

Section 112 (d) (2) of the Clean Air Act (Act) mandates that emission standards be promulgated for sources of hazardous air pollutants, and that the standards “ shall require the maximum degree

of reduction in emissions of the hazardous air pollutants subject to this section (including a prohibition on such emissions, where achievable) that the Administrator, taking into consideration the cost of achieving such emission reduction, and any non

- air quality health and environmental impacts and energy requirements, determines is achievable for new or existing sources in the category or subcategory to which such emission standard applies ...” The se standards are referred to as Maximum Achievable Control Technology (MACT ) standards.

Section 112(d)(4) of the Act states that, “ With respect to pollutants for which a health threshold has been established, the Administrator may consider such threshold level, with an ample margin of safety, when establishing emission standards under this subsection. ” In other words, for hazardous air pollutants (HAP) with a health threshold, standards may be promulgated under a process different from that otherwise specified in Section 112(d), and these standards are referred

to as health

- base d emission limitations (HBEL). This memorandum documents a risk assessment performed to determine an HBEL for acid gases for the Brick and Structural Clay

Products (BSCP) Manufacturing source category.

### 2

Summary The purpose of the assessment was to deter mine a level of emissions that would ensure health thresholds for acid gases are not exceeded (with an ample margin of safety) at any facility in the source category. To determine this level, unit emissions (one ton per year) of hydrochloric acid (HCl) we re assigned to each facility in the source category , and this level was used as the

emissions input into EPA’s Human Exposure Model (HEM 3 ). Using the unit emissions along with emission release pa rameters for each facility, HEM 3 provide d estimates of ambie nt
concentrations (and noncancer hazard indices based on those concentrations ) per unit emissions near the facilities, based on meteorological data near each facility, and at the c ensus block centroid locations used as surrogates for human exposure. Using the highest modeled chronic

concentration for any facility , the unit emissions were scaled up such that an emissions level equivalent to a target

- organ

- specific hazard index (TOSHI) of one (to one significant figure)

could be estimated. This level is 250 tons per year (tpy) of HCl

- equivalent emissions, with the equivalency based on the chronic Reference Concentration (RfC) values for the acid gases , and

is equivalent to 175 t py per year of hydrofluoric acid (HF) or 1.9 tpy of chlorine (Cl 2 

### )

. Because

the 25 0 tpy level of HCl

- equivalent emissions is based on the chronic RfC values of the acid

gases, the limit ensures that no chronic threshold for any acid gas would be exceeded. To assess the potential for acute health effects and environmental effects from HC l, HF, and Cl 2 

### , separate

HEM 3 runs were performed for each pollutant at the emissions levels discussed above for each pollutant

.

Facilities Assessed Ninety

- one facilities are estimated to be in the BSCP source category and were included

in this assessment. These facilities are listed in Table 1

.

Table 1 . List of Modeled Facilities Company Name Facility Name Address City State County

Acme Brick Company Acme

- Bennett Tunnel Plant (BTP) 2350 Bennett Rd Millsap TX Parker

Acme Brick Company Acme

- Elgin Plant (ELP/ENP) FM Rd 696 Elgin TX Bastrop

Acme Brick Company Acme

- Eureka Plant (EBP) E Hwy 64, P.O.

Box 379 Clarksville AR Johnson

Acme Brick Company Acme

- Holly Springs Plant (HSP) 700 Hwy 7 N Holly Springs MS Marshall

Acme Brick Company Acme

- Kanapolis Plant (KAP) 1915 Ave L Kanopolis KS Ellsworth

Acme Brick Company Acme

- Ochs Brick Plant (AOP) 915 E Rock St Springfield MN Brown

Acme Brick Company Acme

- Perla Plant (PEP/PWP) US Hwy 67 N Malvern AR Hot Spring

Acme Brick Company Acme

- Texas Clay Plant (TCP) W Bartlett St Malakoff TX Henderson

Acme Brick Company Acme

- Tulsa Plant (TUP) 4103 Dawson Rd Tulsa OK Tulsa

Acme Brick Company Acme

- Wheeler Plant (WTP) 2905 Dan Ave,
P.O. Box 250 Jonesboro AR Craighead

### 3

Company Name Facility Name Address City State County

Acme Brick Company Jenkins

- Coosaada

Plant 6250 Coosada Rd Coosaada AL Elmore American Eagle
Brick Co American Eagle
Brick Co 1000 McNutt Rd Sunland Park NM Dona Ana

Belden Brick Company Belden

- Plant #2 Sugarcreek 225 E Main St Sugarcreek OH Tuscarawas

Belden Brick Company Belden

- Plant #3 Sugarcreek 225 E Main St Sugarcreek OH Tuscarawas

Belden Brick Company Belden

- Plant #6 Sugarcreek 225 E Main St Sugarcreek OH Tuscarawas

Belden Brick Company Belden

- Plant #8 Sugarcreek 225 E Main St Sugarcreek OH Tuscarawas

Belden Brick Company Belden

- Plant #9 Sugarcreek 225 E Main St Sugarcreek OH Tuscarawas

Belden Brick Company Belden

- Plant 1 Strasburg 7666 Reed Road

NW Strasburg OH Tuscarawas

Boral Bricks Inc. Boral

- Atlanta Plant 5472 Oakdale Rd Smyrna GA Cobb

Boral Bricks Inc. Boral

- Augusta

Plant 6 1449 Doug Barnard Parkway Augusta GA Richmond

Boral Bricks Inc. Boral

- Bessemer
Plant #5 5501 Vulcan Rd Bessemer AL Jefferson

Boral Bricks Inc. Boral

- Bessemer

Plant #6 8250 Hopewell
Rd. SE Bessemer AL Jefferson

Boral Bricks Inc. Boral

- Gleason

Plant Old Hwy 22, P.O.

Box 72 Gleason TN Weakley

Boral Bricks Inc. Boral

- Henderson Facility 1309 Kilgore Dr Henderson TX Rusk

Boral Bricks Inc. Boral

- Muskogee

Plant 3101 West 53rd
St S Muskogee OK Muskogee

Boral Bricks Inc. Boral

- Phenix City

Plant 3 100 Brickyard Rd,
Plant 3 Phenix City AL Russell

Boral Bricks Inc. Boral

- Phenix City

Plant 4 100 Brickyard Rd,

Plant 4 Phenix City AL Russell

Boral Bricks Inc. Boral

- Salisbury

Plant 700 N Long St Salisbury NC Rowan

Boral Bricks Inc. Boral

- Terre Haute

Plant 5601 East Price

Drive Terre Haute IN Vigo

Certainteed Corporation Certainteed Corporation

Ludowici 4757 Tile Plant

Rd New Lexington OH Perry
Cherokee Brick &
Tile Co Cherokee Brick &

Tile 3250 Waterville

Rd Macon GA Bibb

Columbus Brick
Co Columbus Brick Company 114 Brickyard Rd Columbus MS Lowndes

Commercial Brick Corp Commercial Brick Corp Old Hwy 270 Wewoka OK Seminole

Continental Brick
Co Continental Brick

Martinsburg 1441 Charles

Town Rd Martinsburg WV Berkeley Cunningham Brick Company,

Inc Cunningham

Cleveland Co 1622 Longbranch

Rd Grover NC Cleveland Cunningham Brick Company,

Inc Cunningham

Thomasville 1437 Cunningham

Brick Yard Rd Thomasville NC Davidson

### 4

Company Name Facility Name Address City State County Elgin

- Butler Brick
Co Elgin Butler Plant FM 696, P.O. Box

546 Elgin TX Bastrop Endicott Clay
Products Co Endicott Clay

Products 57120 707th Rd Fairbury NE Jefferson General Finance,

Inc General Finance

Cloud Ceramics RR 3, P.O. Box

369 Concordia KS Cloud

General Shale Brick, Inc General Shale

Brick

- Plant 40 121 Turner Bend

Rd Coosa GA Floyd

General Shale Brick, Inc General Shale

Brick

- Plants 35 &

36 770 Webster Rd Blue Ridge (Roanoke) VA Botetourt

General Shale Brick, Inc General Shale

Brick

- Plants 6 & 28 Rt 1, Hwy 11

- E,

Box 460 Atkins (Marion) VA Smyth

General Shale Brick, Inc General Shale

Corbin

- Plant 33 16 Perkins Lane Woodbine KY Whitley

General Shale Brick, Inc General Shale

Moncure Facility 300 Brick Plant

Rd Moncure NC Chatham

General Shale Brick, Inc General Shale

Robinson Brick
Co.

- Plant 2 401 N Santa Fe

Rd Denver CO Denver

Glen Gery Glen

- Gery Corporation

- Capitol 9905 Godwin

Drive Manassas VA Manassas City

Glen Gery Glen

- Gery Corporation

- Bigler State Route #970 Bigler PA Clearfield

Glen Gery Glen

- Gery Corporation

Caledonia 5692 Rinker Rd Caledonia OH Marion

Glen Gery Glen

- Gery Corporation

Marseilles 1401 Broadway
St Marseilles IL LaSalle

Glen Gery Glen

- Gery Corporation

Redfield 1519 Old Hwy 6 Redfield IA Dallas

Glen Gery Glen

- Gery Corporation

- York 1090 E Boundary

Ave York PA York

Hanson Brick East, LLC Hanson

- Monroe Hwy No. 74, P.O.

Box 5012 Monroe NC Union

Hanson Brick East, LLC Hanson

- Athens 200 Athens Brick

Rd Athens TX Henderson

Hanson Brick East, LLC Hanson

- Columbia

- Plant 2 5100 Brickyard

Rd Columbia SC Richland

Hanson Brick East, LLC Hanson

- Elgin Rt.6, Box 338 Elgin TX Bastrop

Hanson Brick East, LLC Hanson

- Mineral

Wells East 7510 Hwy 180 E Mineral Wells TX Palo Pinto

Hanson Brick East, LLC Hanson

- Ninety Six 624 Brickyard Rd Ninety

- Six SC Greenwood

Hanson Brick East, LLC Hanson

- Roseboro 2981 Autry Hwy,
P.O. Box 518 Roseboro NC Sampson

Hanson Brick East, LLC Hanson

- Stanton 2014 Morris
Creek Rd Stanton KY Powell

Hebron Brick Company Hebron Brick Plant 1000 Washington Ave, E Hebron ND Morton

### 5

Company Name Facility Name Address City State County Henry Brick Company, Inc Henry Brick 3409 Water Ave Selma AL Dallas

Higgins Brick Co Higgins Brick 15920 Pomona

Rincon Rd Chino Hills CA San Bernardino

International Chimney Corp Continental Clay

Kittanning 260 Oak Ave Kittanning PA Armstrong

Interpace

Industries Inc Interpace Industries 736 W Harrisville Rd, P.O. Box

12118 Ogden UT Weber

Ironrock Capital Ironrock Capital 1201 Millerton Rd,
SE Canton OH Stark

Kansas Brick and
Tile Co Kansas Brick and

Tile Hwy 281 Hoisington KS Barton Kasten Clay
Products Co Kasten Clay

Products 713 Lee Ave, Hwys 25 & 61 Jackson MO Cape Girardeau

L.P. McNear Brick Co, Inc McNear Brickyard 1 McNear Brickyard Rd San Rafael CA Marin

Lee Brick and
Tile Co Lee Brick Sanford Facility 3704 Hawkins

Ave Sanford NC Lee Marion Ceramics,

Inc Marion Ceramics 2245 Blue Brick Ct, Hwy 301 N Pee Dee SC Marion

McAvoy Brick Co McAvoy Brick 140 McAvoy Lane, P.O. Box

468 Phoenixville PA Chester

Mohawk

Industries Dal

- Tile, Fayette,

Alabama 1470 Country Rd,
21 S Fayette AL Fayette

Mohawk

Industries Dal

- Tile, Lewisport, Kentucky 675 Melanie Lane Lewisport KY Hancock

Mutual Materials
Co Mutual Materials

Mica 10627 S State Hwy 27 Mica WA Spokane

Mutual Materials
Co Mutual Materials

Newcastle 6620 Coalcreek Parkway SE Renton WA King Old Virginia Brick
Co Old Virginia

Madison Heights Mitchell Bell Rd Madison Heights VA Amherst Old Virginia Brick
Co Old Virginia

- Salem 2500 W Main St Salem VA City of Salem

Pacific Clay

Products Pacific Clay

Products

- Lake

Elsinore 14741 Lake St Lake Elsinore CA Riverside

Pine Hall Brick Co, Inc Pine Hall

- Madison

Plant 634 Lindsay Bridge Rd Madison NC Rockingham

Ragland Clay Products, LLC Ragland Clay

Products J.C. Ford Industrial Dr, P.O.

Box 160 Ragland A L St. Clair

Richards Brick
Co Richards Brick 234 Springer Ave Edwardsville IL Madison Sioux City Brick
and Tile Co Sioux City

- Adel

Plant 1831 W Main St,
P.O. Box 35 Adel IA Dallas

Sioux City Brick
and Tile Co Sioux City

Sergeant Bluff

Plant 504 F St Sergeant Bluff IA Woodbury

Statesville Brick
Co Statesville Brick 391 Brickyard Rd Statesville NC Iredell

### 6

Company Name Facility Name Address City State County

Summit Pressed
Brick and Tile Co Summit

- Brick Plant and Storage Yard 13th and Erie St Pueblo CO Pueblo Summitville Tiles,

Inc. Summitville Tiles,

Inc.

- Minerva Plant 1310 Alliance Rd,
P.O. Box 283 Minerva OH Stark

Triangle Brick Triangle Brick

Merry Oaks Plant 294 King Rd Moncure NC Chatham

Triangle Brick Triangle Brick

Wadesboro Plant 2960 Hwy 52 N Wadesboro NC Anson

Watsontown
Brick Co Watsontown Brick S Main St, P.O.

Box 68 Watsontown PA Northumberland

Whitacre Greer Whitacre Greer 1400 S Mahoning

Ave Alliance OH Stark

Yankee Hill Brick

and Tile Yankee Hill Brick

and Tile 3705 S Coddington Lincoln NE Lancaster



### Emissions and Release Parameters As discussed above, unit emissions (1 tpy) of HCl were assigned to each facility, and this level was used as input into HEM3 to estimate the maximum ambient chronic concentration (at census block receptors or other populated recept ors) for each facility. The emissions of the facility with the highest modeled ambient chronic concentration were scaled up such that they were equivalent to a noncancer TOSHI of one. The resulting emissions level is 250 tpy of HCl

equivalent emissions, which is equivalent to 175 tpy of HF or 1.9 tpy of Cl 2 

### . A HEM3 run was made for each pollutant’s emissions level to estimate pollutant

- specific acute concentrations and to create model output files needed to estimate environmental risks. No emissions mul tiplier was

used in HEM3 to account for short

- term emissions being higher than the annual tpy level. The resulting acute modeled estimates reflect 1

- hour emissions being simply the annual emissions level divided by 8760 hours per year.

Facility information and emission release parameters used in HEM3 were obtained mostly from Information Collection Request (ICR) data collected in 2008 through 2011. Where there were data gaps, the data were supplemented with information from various data sources , including an earlier 1997 ICR, EPA’s Envirofacts, title V permits , and information supplied by the Brick Industry Association

. For missing release parameters, conservative default values (e.g., the 25 th


### percentile of stack height, exit velocity , and temperature) were calculated based on the data from

other facilities. Where it was determined that kilns were shut down, inactive, or area sources (true area or synthetic minor), they were not included in the data. For facilities with multiple

stac ks, the facilitywide emissions level was divided evenly by the number of stacks. Where multiple kilns share the same stack, the emissions from those kilns were modeled as being emitted from the single stack.

Dispersion Modeling and Estimating Inhalation E xposures
I nhalation exposure concentrations and potential health risks w ere estimated using HEM3, an inhalation risk model that incorporates the American Meteorological Society/EPA Regulatory Model (AERMOD) dispersion modeling system (AERMOD version 1 3350) . The

AERMOD model is a state

- of

- the

- science Gaussian plume dispersion model that is preferred by

### 7

EPA for modeling point, area, and volume sources of continuous air emissions. 1 

### The model is

used to estimate annual average ambient concentrations through t he simulation of hour

- by

- hour dispersion from the emission sources into the surrounding atmosphere , and can also be used to

estimate short

- term ambient concentrations, with the shortest averaging time being one hour.

Further details on AERMOD can be found in the AERMOD u ser ’ s g uide

, 2 

### and further details on HEM3 can be found in the user’s guides for HEM3. 3 

### For this assessment, annual concentrations were estimated to assess chronic health impacts and the potential for environmental effects, and

1

- hour conce ntrations were estimated to assess acute health impacts. Unless otherwise stated in this document, the modeling methodologies used for this assessment are the same as those used in air toxics assessments performed for the Risk and Technology Review (RTR) program.

The first step in the application of the HEM3 modeling system is to predict ambient concentrations at locations of interest. The AERMOD model options employed are summarized

in Table 2 and are discussed further below

.

Table 2

. AERMOD V ersion 1 3350 M o del O ptions

Modeling Option Selected Parameter

Type of calculations Hourly a mbient c oncentration

Source type Point

Receptor orientation Polar (13 rings and 16 radials) Discrete (census block centroids and additional residential

receptors )

Terrain characterization Actual from USGS 1/3 a rc s econd NED data

Building downwash Not i ncluded

Plume deposition/depletion Not i ncluded

Urban source option Yes

Meteorology 1 year (2011) NWS from nearest site processed with

AERMET 13350 1

1 

### Meteorological data processed with the pre

- public release version of AERMET 13350.

See http://www2.epa.gov/fera/download

- human

- exposure

- model

- hem for a complete listing of

meteorol ogical stations.

The HEM3 estimates chronic and acute ambient concentrations at the geographic centroids of census blocks (using the 2010 Census), and at other receptor locations that can be

1 US EPA, 2005. Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions; Final Rule. 40 CFR Part 51. http://www.epa.gov/EPA

- AIR/2005/November/Day

- 09/a21627.ht m

. 2 US EPA, 2004. User ’s guide for the AMS/EPA regulatory model

– AERMOD. EPA

- 454/B

- 03

- 001. http://www.epa.gov/scram001/7thconf/aermod/aermodugb.pdf.

3 http://epa.gov/ttn/fera/human_hem.html#guide

.

### 8

specified by the user. For chronic exposures, t he model accoun ts for the effects of multiple facilities when estimating concentration impacts at each block centroid , and includes only census blocks with at least one resident (i.e., locations where people may reasonably be assumed to reside rather than receptor points at the fenceline of a facility). A mbient concentrations for all averaging times (e.g., 1

- hour, annual) are calculated u sing modeled one

- hour concentrations at each block centroid. Possible future residential use of currently uninhabited areas is not considered. Census blocks, the finest resolution available in the census data, are typically comprised of approximately 5 0 people or about ten households.

For the facilit ies included in th is assessment

, census block locations were evaluated to determine if they are representative of the residential locations within the blocks. For some facilit ies

, b locks were located on faci lity property or were otherwise not represen tative of

residences , and these blocks were moved to location s that better represent the residential

locations associated with the block s

. There w ere also two census block s with no apparent population, and th ese block s w ere removed. In addition to the changes to the census blocks, if residential locations could not be represented by a single receptor (that is, the residences were spread out over the block), we added additional receptors for residences nearer to the facility

than the centroid. The census block adjustments and additional receptors are listed in Table 3

.

Table 3

. Revised Census Block Centroid Locations and Additional Receptors for the BSCP Source Category

Centroid Revisions

Block ID NEI ID New
Latitude New Longitude Comment

010510312001075 32.492083

- 86.332795

011130308001001 32.425681

- 84.971158

050310007002024 35.853702

- 90.757445

060375412005014 Remove block

- no apparent population

081010008003004 38.280498

- 104.596054

171194030021015 38.811545

- 89.944182

181095102024036 39.575639

- 86.366234

240217675003020 39.601588

- 77.33552

290318804002002 37.377383

- 89.673108

371570407001022 36.378258

- 79.997247

371590508002004 35.67362

- 80.442701

390998130005030 40.90251

- 81.084256

390998130005035 40.90776

- 81.086366

391010101003049 40.637602

- 82.973929

391570213001030 40.516993

- 81.647809

391570214002124 40.398698

- 81.55794

420333310002113 40.98331

- 78.309698

421330104005013 39.958437

- 76.706338

450479707011071 34.162029

- 81.954354

490351152091021 Remove block

- no apparent population

540039720006022 39.428952

- 77.953003

010510312001075 32.492083

- 86.332795 Additional Receptors

01051NEIAL0510010 32.491865

- 86.327732

### 9

01051NEIAL0510010 32.49079

- 86.326324
28087NEIMS1773 33.513205

- 88.410343

37157NEI46185 36.376582

- 79.997157

17119NEIIL119803A 38.810445

- 89.946363

39101NEI11415 40.635508

- 82.97757
42005NEIPARBSCP17 40.820493

- 79.516566
20009NEIKSRBSCP17 38.469834

- 98.773762

37037NEI44992 35.648122

- 78.999545

21197NEIKY1068 37.876169

- 83.862206

21197NEIKY1068 37.873258

- 83.855161

27015NEIMN1189 44.239653

- 94.952976

45047NEI41366 34.150217

- 81.953853
48021NEITXRBSCP77 30.327978

- 97.334404

53063NEIWA0122 47.562597

- 117.216861



### One year of meteorological data (2011) w as used for each facility. These data were processed using EPA’s AERMET (version 1 3350 ) program , which is the meteorological data preprocessor for AERMOD. T he ADJ_U* non

- Default BETA option that adjust s the surface friction velocity (u* or ustar) for low wind speed stable conditions was used. The AERMINUTE

pro gram (version 11325) is a data preprocessor for AERMET, and was used to process 1

- minute

wind data to generate hourly average winds for input to AERMET

. The EPA’s AERSURFACE

tool (version 13016) was also used to process land cover data to determine the surface

characteristics for use in AERMET.

Chronic n oncancer health hazards are expressed by comparing a chronic exposure to a reference level as a ratio. The “hazard quotient” (HQ) is the estimated exposure divided by a reference level (e.g., the RfC). For a given HAP, exposures at or below the reference level (HQ≤1) are not likely to cause adverse heal th effects. As exposures increase above the reference level (HQs increasingly greater than 1), the potential for adverse effects increases

. For a typical risk assessment where multiple pollutants are co

- emitted, we aggreg at e noncancer HQs of HAPs

that act by similar toxic modes of action, or (where this information is absent) that affect the same target organ. This process creates, for each target organ, a TOSHI, defined as the sum of hazard quotients for individual HAPs that affect the same organ or orga n system. Because we performed HEM3 model runs for each acid gas individually, we did not aggregate HQ values of different acid gases. Of course, multiple acid gas pollutants are emitted at BSCP facilities, but the 250 tpy level of HCl

- equivalent emission s ensures that a TOSHI of one is not exceeded as long as the HCl

- equivalent emissions do not exceed 250 tpy.

Acute Health Risk Screening For the assessment of potential health risks from acute exposures to the acid gases, we performed a screening assessm ent using conservative assumptions that in combination approximate a worst

- case exposure. The result of this screening process is that either the facility being assessed poses no potential acute health risks (i.e., it “screens out”), or that it requires

f urther, more refined

, assessment. The acute exposure scenario assumed w orst

- case meteorology (from one year of local meteorology) and that a person is located downwind at the point of maximum impact during this same worst

- case 1

- hour period, but no nearer to the source than 100

meters.

### 10

Screening for potentially significant acute inhalation exposures also followed the HQ approach. We divided the maximum estimated acute exposure by each available short

- term threshold value to develop an array of HQ values relative to the various acute endpoints and thresholds. In general, when none of these HQ values are greater than one, there is low potential for acute risk. In those cases where HQ values above one are seen, additional information is used to determine if there is a potential for significant acute risks. Refined assessment for facilities in the BSCP source category included using ae rial imagery of the facilit ies to determine

the maximum offsite 1

- hour concentrations.

Acid Gases Environmental Risk Screening In addition to potential health impacts, EPA evaluated the potential for environmental impacts when considering whether to exercise discretion under CAA Section 112(d)(4). 4 

### We applied the environmental risk screen methodology that is use d in the R TR Program under section 112 of the CAA to evaluate the potential for chronic exposure to HCl and HF emitted by

BSCP facilities to cause phytotoxicity and reduced productivity of plants.

Although chlorine may also be emitted from BSCP facilities, chlorine gas is so reactive that it is not expected to remain in the environment very long after it is released. Chlorine immediately reac ts with both organic and inorganic materials that it comes into contact with. Chlorine undergoes direct photolysis in the air and its half

- life in the troposphere is on the order of several minutes. Therefore, it is not considered in the environmental ris k screening for the BSCP source category.

The environmental screen uses air concentrations of HF and HCl from the HEM3 model used in the human health exposure and risk analysis. The HEM3 modeling domain extends 50 km from the center of the facility. The defaults for HEM3 are to model 13 concentric rings at various distances (out to 50 km) from the facility with 16 concentration data points (one every 22.5 degrees) on each ring. Therefore, there are a total of 208 data points. All 16 data points on ring s that we determine to be onsite are excluded from the 208 total. Therefore, the total number of data points included in the analysis generally varies depending on facility size. For the BSCP source category, we used aerial imagery of the facilities to d etermine that 200 m is a typical facility radius, and we excluded data points inside this radius.

We derive d an area

- weighted average offsite annual ambient air concentration for HF and

HCl over the 50

- km modeling domain for each facility

. The area

- weighted average

concentrations wer e compared directly to the appropriate ecological benchmarks for each pollutant by dividing the area

- weighted average concentration by the appropriate ecological

benchmark. The result is called a hazard quotient (HQ). An HQ greater than one indicated that

the area

- weighted average concentration exceeded the ecological benchmark.

Dose

- Response Information As discussed above, we assessed the pote ntial for health effects f rom 1

- hour and annual exposures, and the p otential for environmental effects from annual modeled concentrations. The development and/ or use of health reference values and ecological values are discussed below.

4 See Portland C ement NESHAP Final Rule , 75 FR 54970, 54986/3 (Sept 9, 2010).

### 11

Chronic Exposures

Dose

- response assessment for chronic exposure to acid gases w as base d on existing recommendations for HAPs by the EPA Office of Air Quality Planning and Standards (OAQPS)

. 5 

### This information has been obtained from various sources and prioritized according to (1) conceptual consistency with EPA risk assessment guidelines an d (2) level of peer review received. The prioritization process was aimed at incorporating into our assessments the best available science with respect to dose

- response information. The recommendations are based on the following sources, in order of prio rity:

1) US Environmental Protection Agency (EPA). EPA has developed a dose

response assessment for chronic exposure to HCl. Th e dose

- response assessment for HCl provides a qualitative statement regarding the strength of scientific data and specifies an RfC to protect against effects other than cancer

. The RfC is defined as an “estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.” The EPA disseminates dose

- response assessment information in several forms, based on the level of review. The Integrated Risk Information System (IRIS) 6 

### is an EPA database that co ntains scientific health assessment information, including dose

- response information. All IRIS assessments since 1996 have also undergone independent external peer review. The current IRIS process includes review by EPA scientists, interagency reviewers f rom other federal agencies, and the public, and peer review by independent scientists external to EPA. New IRIS values are developed and old IRIS values are updated as new health effects data become available. Refer to the “IRIS Track” website for

detail ed information on status and scheduling of current individual IRIS assessments and updates (http://cfpub.epa.gov/ncea/iristrac/index.cfm).

2) US Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR, which is part of the US Department of Health and Human Services, develops and publishes Minimum Risk Levels (MRLs) 7 

### for inhalation and oral exposure to many toxic substances

, including chlorine . As stated on the ATSDR web site: “Following discussions with scientists within the Department of Health and Human Services (HHS) and the EPA, ATSDR chose to adopt a practice similar to that of the EPA's Reference Dose (RfD) and Reference Concentration (RfC) for deriving substance specific health guidance levels for non neoplastic endpoints.” The

MRL is defi ned as “an estimate of daily human exposure to a substance that is likely to be without an appreciable risk of adverse effects (other than cancer) over a specified duration of exposure.” ATSDR describes MRLs as substance

- specific estimates to be used by h ealth assessors to select environmental contaminants for further evaluation. Exposures above an MRL do not necessarily represent a threat, and MRLs are therefore not intended for use as predictors of adverse health effects or for setting cleanup levels.

5 US EPA, 2012. Table 1. Prioritized Chronic Dose

- Response Values (5/21/12). Office of Air Quality Planning and Standards. http://www.epa.gov/ttn/atw/toxsource/table1.pdf.

6 US EPA, 2006. Integrated Risk Information System. http://www.epa.gov/iris/index.html.

7 US Agency for Toxic Substances and Disease Registry. 2006. Minimum Risk Levels (MRLs) for Hazardous Substances. http://www.atsdr.cdc.gov/mrls/index.html.

### 12

3) California Environmental Protection Agency (CalEPA). The CalEPA Office of Environmental Health Hazard Assessment has developed a dose

- response assessment for HF

for health effects other than cancer. The process for developing these assessments is simi lar to that used by EPA to develop IRIS values and incorporates significant external scientific peer review. As cited in the CalEPA Technical Support Document for developing their chronic assessments : “The guidelines for developing chronic inhalation exp osure levels incorporate many recommendations of the U.S. EPA 8 

### and NAS 9 

### .” The non

- cancer information includes available inhalation health risk guidance values expressed as chronic inhalation reference exposure levels (RELs) 10 

### . CalEPA defines the REL as “t he concentration level at or below which no health effects are anticipated in the general human population.”

The acid gases, their quantitative inhalation chronic non cancer dose

- response values, and the

source of each value are listed in Table 4.

Table 4. Dose

- Response Values for Chronic Inhalation Exposure to Acid Gases

Pollutant CAS Number 11 RfC (mg/m3) Source

Hydrochloric acid 7647010 0.02 IRIS
Hydrofluoric acid 7664393 0.0 14 CAL

Chlorine 7782505 0.00 0 1 5 ATSDR



### A cute Exposures

Dose

- response assessment for acute exposure to acid gases was also based on the existing recommendations of OAQPS for HAPs. 12 

### Depending on availability, the results from screening acute assessments are compared to both “no effects” reference levels for the general public, such as the California Reference Exposure Levels (RELs), as well as emergency response levels, such as Acute Exposure Guideline Levels (AEGLs) and Emergency Response Planning Guidelines (ERPGs), with the recognition that the ultimate inter pretation of any potential risks associated with an estimated exceedance of a particular reference level depends on the definition of that level and any limitations expressed therein

.

California Acute Reference Exposure Levels (RELs). The California Envi ronmental Protection Agency (CalEPA) has developed acute dose

- response reference values for many substances, expressing the results as acute inhalation Reference Exposure Levels (RELs). The acute REL (http://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defin ed by CalEPA as “the concentration level at or below which no adverse health effects are anticipated for a specified

8 US EPA, 1994. US Environmental Protection Agency. Methods f or Derivation of Inhalation Reference Concentrations and Application of Inhalation Dosimetry. EPA/600/8

- 90/066F. Office of Research and Development. Washington, DC: U.S.EPA.

9 NRC, 1994. National Research Council. Science and Judgment in Risk Assessment. W ashington, DC: National Academy Press.

10 CA Office of Environmental Health Hazard Assessment, 2005. Chronic Reference Exposure Levels Adopted by OEHHA as of December 2008. http://www.oehha.ca.gov/air/chronic_rels/AllChrels.html.

11 Chemical Abstract Servi ces identification number. For groups of compounds that lack a CAS number we have used a surrogate 3

- digit identifier corresponding to the group’s position on the CAA list of HAPs.

12 US EPA, 2011. Table 2. Acute Dose

- Response Values for Screening Risk As sessments (12/19/2011). Office of Air Quality Planning and Standards. http://www.epa.gov/ttn/atw/toxsource/table2.pdf.

### 13

exposure duration. 13 

### RELs are based on the most sensitive, relevant, adverse health effect reported in the medical and toxicological litera ture. RELs are designed to protect the most sensitive individuals in the population by the inclusion of margins of safety. Since margins of safety are incorporated to address data gaps and uncertainties, exceeding the REL does not automatically indicate an adverse health impact.” Acute RELs are developed for 1

- hour (and 8

- hour) exposures. The values incorporate uncertainty factors similar to those used in deriving EPA’s Inhalation Reference Concentrations (RfCs) for chronic exposures (and, in fact,

Calif ornia also has developed chronic RELs).

Acute Exposure Guideline Levels (AEGLs). AEGLs are developed by the National Advisory Committee (NAC) on Acute Exposure Guideline Levels (NAC/AEGL) for Hazardous Substances, and then reviewed and published by the N ational Research Council

. As described in the Committee’s “Standing Operating Procedures (SOP)”, 14 

### AEGLs “represent threshold exposure limits for the general public and are applicable to emergency exposures ranging from 10 min to 8 h.” Their intended appl ication is “for conducting risk assessments to aid in the development of emergency preparedness and prevention plans, as well as real time emergency response actions, for accidental chemical releases at fixed facilities and from transport carriers.”

The d ocument states that “the primary purpose of the AEGL program and the NAC/AEGL Committee is to develop guideline levels for once

- in

- a

- lifetime, short

- term exposures to airborne concentrations of acutely toxic, high

- priority chemicals.” In detailing the int ended application of AEGL values, the document states that, “It is anticipated that the AEGL values will be used for regulatory and nonregulatory purposes by U.S. Federal and State agencies, and possibly the international community in conjunction with chem ical emergency response, planning, and prevention programs. More specifically, the AEGL values will be used for conducting various risk assessments to aid in the development of emergency preparedness and prevention plans, as

well as real

- time emergency re sponse actions, for accidental chemical releases at fixed facilities and from transport carriers.”

The NAC/AEGL defines AEGL

- 1 and AEGL

- 2 as:

“AEGL

- 1 is the airborne concentration (expressed as ppm or mg/m3) of a substance above which it is predicted t hat the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic nonsensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure. ”

“AEGL

- 2 is the airborne concentration (expressed as ppm or mg/m3) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long

- lasting adverse health effects or an impaired ability to escape.”

“Airborne concentrations below AEGL

- 1 represent exposure levels that can produce mild and progressively increasing but transient and nondisabling odor, taste, and sensory irritation or certain asymptomatic, nons ensory effects. With increasing airborne concentrations

13 CA Office of Environmental Health Hazard Assessment, 2000. All Acute Reference Exposure Levels developed by OEHHA as of May 2000. h ttp://www.oehha.ca.gov/air/acute_rels/allAcRELs.html

. 14 http://www.epa.gov/opptintr/aegl/pubs/sop.pdf

### 14

above each AEGL, there is a progressive increase in the likelihood of occurrence and the severity of effects described for each corresponding AEGL. Although the AEGL values represent

threshold level s for the general public, including susceptible subpopulations, such as infants, children, the elderly, persons with asthma, and those with other illnesses, it is recognized that individuals, subject to unique or idiosyncratic responses, could experience t he effects described at concentrations below the corresponding AEGL.”

Emergency Response Planning Guidelines (ERPGs). The American Industrial Hygiene Association (AIHA) has developed Emergency Response Planning Guidelines (ERPGs) 15 

### for acute exposures at three different levels of severity. These guidelines represent concentrations for exposure of the general population (but not particularly sensitive persons) for up to 1 hour associated with effects expected to be mild or transient (ERPG

- 1), irreversible or serious (ERPG

- 2), and potentially life

- threatening (ERPG

- 3).

ERPG values 16 

### are described in their supporting documentation as follows: “Emergency Response Planning Guidelines (ERPGs) were developed for emergency planning and are

intended as health base d guideline concentrations for single exposures to chemicals. These guidelines (i.e., the ERPG Documents and ERPG values) are intended for use as planning tools for assessing the adequacy of accident prevention and emergency response plans, including

tran sportation emergency planning and for developing community emergency response plans. The emphasis is on ERPGs as planning values: When an actual chemical emergency occurs

there is seldom time to measure airborne concentrations and then to take action.”

ERPG

- 1 and ERPG

- 2 values are defined by AIHA as follows:

“ERPG

- 1 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour without experiencing other than mild transient

adverse health effects or without perceiving a clearly defined, objectionable odor.”

“ERPG

- 2 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action.”

The acid gases, their quantitative inhalation acute dose

- response values, and the source of each

value are listed in Table 5

.

Table 5. Do se

- Response Values for Acute Inhalation Exposure to Acid Gases

Pollutant CAS Number AEGL

- 1 (1

- hr) (mg/m 3 ) AEGL

- 2 (1

- hr) (mg/m 3 ) ERPG

- 1 (mg/m 3 ) ERPG

- 2 (mg/m 3 ) REL
Hydrochloric acid 7647010 2.7 33 4.5 30 2.1
Hydrofluoric acid 7664393 0.82 20 1.6 16 0.24

15 American Industrial Hygiene Association, 2011. Current AIHA ERPG Values. http://www.aiha.org/insideaiha/GuidelineDevelopment/ERPG/Documents/2011erpgwe elhandbook_table

- only.pdf.

16 http://www.aiha.org/insideaiha/GuidelineDevelopment/ERPG/Pages/default.aspx

.

### 15

Pollutant CAS Number AEGL

- 1 (1

- hr) (mg/m 3 ) AEGL

- 2 (1

- hr) (mg/m 3 ) ERPG

- 1 (mg/m 3 ) ERPG

- 2 (mg/m 3 ) REL

Chlorine 7782505 1.5 5.8 2.9 8.7 0.21



### E cological Risk Benchmarks for Acid Gases The environmental screening analysis evaluated potential damage and reduced productivity of plants due to chronic direct exposure to HCl and HF in the air. The chronic 90

- day benchmarks used in the environmental risk screen for the acid gases are shown in Table 6 and discussed in the following section.

Table 6. Acid Gas Benchmarks Included in the Environmental Risk Screen

a

- Note that the human health RfC is 20 μg/m3, which is lower than the ecological ben chmark.



### Hydrogen Chloride

. For HCl, EPA identified chronic benchmark concentrations as

described in a 2009 EPA document on RTR risk assessment methodologies. 17 

### The chronic

benchmark for HCl was based on a LOEL from a short

- term exposure (20 minutes) that related

HCl concen tration to “changes” in the leaves of 7 out of 8 plant species as reported by Lerman et

al. 18 

### It was the lowest exposure concentration at which effects of any type were seen (visible injury to some proportion of leaves). Haber’s law was used to extrapolat e the 1.5 mg/m 3 

### LOEL

concentration ( 20

- minute exposure ) to a 0.5 mg/m 3 

### concentration expected to produce the same

effect after one hour. The 1

- hr estimated LOEL was extrapolated to a chronic benchmark by dividing by a factor of ten to yield 0.050 mg/m 3



### , or 50 μg/m 3



### .

Hydrogen Fluoride. For HF, EPA used two chronic benchmark concentrations for plants in the environmental screening analysis (Table 6)

. The value of 0.5 μg HF/m 3 

### is based on the Washington State criterion for gaseous HF

, and represents a LOEL . The value of 0.4 μg

HF/m 3 

### is based on the Environment Canada criteria and also represents a LOEL

.

To protect vegetation from adverse effects resulting from HF exposure, the Canadian

Council of Ministers of the Environment 19 

### recommends that HF concentrati ons not exceed 0.4

17 US EPA, 2009. Risk and Technology Review (RTR) Risk Assessment Methodologies: For Review by the EPA’s Science Advisory Board with Case Studies

– MA CT I Petroleum Refining Sources and Portland Cement Manufacturing. EPA

- 452/R

- 09

- 006. http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

18 Lerman, S., O.C. Taylor, and E.F. Darley, 1976. Phytotoxicity of Hydrogen Chloride Gas with a

Short

- Term Exposure. Atmosph eric Environment, Vol.10, pp. 873

- 878.

19 CCME. 1999b. Canadian National Ambient Air Quality Objectives: Process and Status. In: Canadian Environmental Quality Guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. Publication

No. 129 9, ISBN 1

- 896997

- 34

- 1. Available at http://ceqg

- rcqe.ccme.ca/download/en/133/

. Acid Gas Chronic 90

- day Benchmark in μg/m 3

Hydrochloric acid

- NEL 50 a

Hydrofluoric acid

– Plant Community LOEL 0.5
Hydrofluoric acid

– Plant Community LOEL 0.4

### 16

μg/m 3 

### over a 30

- to 90

- day period; HF concentrations can be higher for shorter exposures).

Environment Canada 20 

### defined the effect represented by the level of 0.4 μg HF/m 3 

### as :

"The level above which there are demonstrated effects on human health and/or the environment. It is scientifically based and defines the boundary between the LOAEL and the NOAEL. It is considered to be the level of exposure just below that most likely to

result in a defined and identifiable but minimal effect. T he reference levels have no safety factors applied to them, as they are related directly to the LOAEL, and are the most

conservative estimates of the effect level."

H igh concentrations of HF in the air have also been linked to fluorosis in livestock.

Howe ver, the HF concentrations at which fluorosis in livestock occur are higher than those at which plant damage begins. Therefore, the benchmarks for plants are protective of both plants

and livestock.

Results and Risk Characterization Because the 250 tpy le vel of HCl

- equivalent emissions was determined such that no facility would exceed a TOSHI of one

, no facility in the individual acid gas model runs exceed ed

this level . Therefore, adverse chronic health effects are not likely to occur. However, because

t he emissions equivalency was based on chronic dose

- response values, the 250 tpy level does not necessarily ensure that acute reference levels will not be exceed ed

. For the HCl and Cl 2 

### model runs, there were no facilities with acute screening HQ values exceeding one. For the HF model

run (175 tpy) , there were multiple facilities with screening HQ values (based on the REL) exceeding one, with the highest being an HQ of five

. There was only one facility with an acute screening HQ value based on the AEGL

- 1 that exceeded one, and that value was two . We reviewed these cases by examining aerial imagery of the facilities to determine the maximum offsite HQ values. Table 8 gives the facilities with screening HQ (REL) values exceeding one, along with their scr eening HQ values and maximum offsite HQ values. For the single facility with an HQ (AEGL

- 1) value exceeding one , the maximum offsite HQ value is less than one

.

Table 8. Maximum Acute Screening and Offsite HQ (REL) Values for BSCP Facilities (based on 175 tons per year of HF).

Facility Maximum Acute Screening
HQ (REL) Value Maximum Offsite Acute HQ (REL) Value

48021NEITXRBSCP15 5 2

45067NEISCRBSCP50 5 1

20009NEIKSRBSCP17 5 2

39127NEIROHSCP181 5 2

39157NEIOHRBSCP11 4 1

37045NEI44906 4 2 42097NEIPAT$1908 4 <1

29031NEIMO0006 4 1

20 EC. (Environment Canada). 1996. National Ambient Air Quality Objectives for Hydrogen Fluoride (HF). Science Assessment Document. A Report by the CEPA/FPAC Working Group on Air Quality Objectives and Guidelines. July. ISBN 0

- 662

- 25641

- 7, Catalogue En42

- 17/6

- 1997. Available online at: http://www.bape.gouv.qc.ca/sections/mandats/ap50_rio_tinto_alcan/documents/DQ3.1.1.pdf

### 17

Facility Maximum Acute Screening
HQ (REL) Value Maximum Offsite Acute HQ (REL) Value

35013NEINMRBSCP2 4 <1

42005NEIPARBSCP17 4 2

06071NEICARBSCP63 3 2

01115NEIALRBSCP15 3 1

21091NEIKY091231 3 2

06065NEI22439 2 <1

51775NEIVA7750000 2 1

51683NEIVA6830000 2 1

40133NEIOKRBSCP13 2 <1

37097NEI43753 2 <1

49057NEIUTRBSCP71 2 1

51173NEIVA00011 2 <1 39151NEIOHT$6289 2 1

42029NEIPA23

- 0852 2 <1

53063NEIWA0122 2 <1



### Although the maximum offsite acute HQ (REL) values for several facilities exceed one, we conclude that there is low p otential for acute health effects for several reasons. First, the maximum offsite HQ (REL) value is only two

, and the maximum offsite HQ based on the

AEGL

- 1 is less than one . Also, the acute scenario is conservative in that it assume s t here is a

person p resent at the location and time where the maximum HQ value occurs. Finally, it is unlikely that a facility would emit only HF, and emissions of the other acid gases did not result in HQ values exceeding one.

For HCl, t he environmental risk screen indicated that the area

- weighted average modeled

concentration of HCl around each facility (i.e., the area

- weighted average concentration of all offsite data points in the modeling domain) did not exceed the ecological benchmark. In addition, there was only one facility with a modeled concentration of HCl at an offsite receptor

location that exceeded the ecological benchmark , and that was at a single receptor. For HF, the

environmental risk screen indicated that the area

- weighted average mode led concentration of HF around each facility did not exceed the ecological benchmark. There were multiple facilities

with modeled concentration s of H F at offsite receptor location s that exceeded the ecological

benchmark , but the area over which the value was exceeded was less than one percent of the offsite modeling domain for each facility, indicating that there would not be any significant or widespread environmental effects.

In summary, we conclude that 250 tpy of HCl

- equivalent emissions per BSCP faci lity is unlikely to result in adverse chronic or acute human health effects at any facility in the source

category . The emissions level is s uch that the chronic health reference values are not exceeded at any facility. A lthough the acute screening assessm ent indicates there are small exceedances of the acute REL values at some facilities, we conclude that there is low potential for acute health effects because the maximum offsite HQ (REL) value is only two and the acute exposure

scenario is conservative in that it assumes there is a person present at the location and time where the maximum HQ value occurs . We also conclude that there is low potential for significant and

### 18

widespread environmental effects. For HCl and HF, the environmental risk screen indicated that

the area

- weighted average modeled concentrations around each facility (i.e., the area

- weighted average concentration of all offsite data points in the modeling domain) did not exceed the ecological benchmark s

. In addition, the area over which t he HCl or HF benchmarks w ere exceeded w as less than one percent of the offsite modeling domain for each facility in the

category.