UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

US EPA Region 5 

Air and Radiation Division

Chicago, IL 60604

DATE: April 25, 2005

SUBJECT: Residual Risk Test for the Ferroalloys Production Source Category

FROM: Jaime Julian, Margaret Sieffert, Rae Trine, George Bollweg

U.S. EPA Region 5 Air and Radiation Division (AT-18J)

TO: Dave Guinnup, Leader

Risk and Exposure Assessment Group (C404-01)

Emission Standards Division

Office of Air Quality Planning and Standards (OAQPS)

Research Triangle Park, NC 27711

Introduction

The purpose of this memorandum is to describe methods and results of the residual risk test for

the Ferroalloys Production source category (“Ferroalloys Production”).

The residual risk test is conducted by U.S. EPA at the beginning of the residual risk rule

development process. The purpose of the residual risk test is to determine whether the source

category can be shown at the outset not to require a residual risk rule on the basis of data already

in U.S. EPA’s possession and a relatively simple and health-protective analysis. Under the

requirements of the Clean Air Act of 1990, U.S. EPA will not promulgate additional emission

standards for a source category if existing maximum achievable control technology (MACT)

standards provide an “ample margin of safety” to protect public health and are sufficient to

prevent adverse environmental impacts (CAA section 112(f)(2)(A)).

The residual risk test is not intended to be an exhaustive assessment. Rather, it is an initial

attempt to determine if enough is known to eliminate the source category as one of ongoing

concern or to justify pursuing its continued evaluation. U.S. EPA’s failure to remove a source

category from the residual risk process at this stage in no way suggests that a residual risk rule is

inevitable, only that we lack sufficient data at this time to forego such a rule.

There are currently two known facilities in the Ferroalloys Production source category, both in

Washington County, Ohio. The present exercise evaluated only one pollutant (manganese; Mn)

released from what is believed to be the larger (i.e. greater Mn emissions) of these two facilities. 

Results below show noncancer hazard well above a hazard quotient (HQ) of 1 in this facility’s

geographic vicinity, supporting the idea that U.S. EPA does not currently have sufficient

information to remove Ferroalloys Production from consideration for a residual risk rule. 
2

Methods and Results

1. Scope and approach

This Ferroalloys Production residual risk test focuses on human health (it excludes “ecological”

or “environmental” effects) by estimating potential human health noncancer hazard associated

with air pollutant emissions. The Ferroalloys Production source category includes two known

sources subject to MACT, both in Washington County, Ohio: the Eramet Marietta facility

(“Eramet”) located near Marietta OH, and Globe Metallurgical, Inc. (“Globe”), near Beverly OH. 

The present assessment evaluated only Eramet based on information described below. Globe

(Beverly OH) is about 16 miles N/NW of Eramet (see Figure 1a) and started relevant production

in January 2005. It is not further evaluated here. We believe that if available evidence shows

potentially elevated risks or hazards associated with emissions from either facility, the risk test

memo can adequately demonstrate that U.S. EPA does not currently have sufficient information

to remove the Ferroalloys Production source category from consideration for a residual risk rule.

An Eramet facility schematic is included as Attachment 1. U.S. EPA’s 2002 Toxic Release

Inventory (TRI) indicates that Eramet remains the largest emitter of airborne Mn compounds in

the U.S.; substantial 2002 air emissions of ammonia (168,300 lbs), chromium (14,600 lbs), and

mercury (527 lbs) from Eramet are also listed in this TRI report. Ohio EPA air monitoring data

for Mn from 2000-2004 show average Mn air concentrations regularly exceeding U.S. EPA’s

inhalation Reference Concentration (RfC; 0.05 μg/m3) at a site less than 5 miles north-northeast

of the facility (Figure 8). 

Because available air monitoring data showed elevated Mn air concentrations, the residual risk

test air dispersion modeling exercise evaluates only Mn air emissions from Eramet. Not included

here are assessment of potential cancer risk from Eramet’s air emissions, pollutants other than

Mn, potential environmental (“ecological”) effects and, except for the brief mention of Globe,

other Marietta sources. These were not pursued for this residual risk test because results below

show that Mn-related human health noncancer hazard associated with Eramet’s emissions could

not be eliminated as a concern. We show that inhalation hazard for the “individual most

exposed” (i.e. a hypothetical individual living near the facility at the centroid of a populated

census block) exceeds the relevant reference criterion (i.e. a hazard quotient [HQ] greater than 1,

described more fully in section 4 below). We believe that the potential hazard associated with

Mn alone satisfies the risk test and supports moving to the next phase of the residual risk

assessment process. 

2. Air Dispersion Modeling of Eramet’s Mn air emissions

Air dispersion modeling of Mn air emissions from Eramet was done through a contract

administered by the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR

became involved separately from U.S. EPA after receiving a May 2000 petition from U.S.

Senator Mike DeWine to evaluate potential health effects of air pollution following complaints

from residents in the Marietta, OH vicinity. Among other issues, ATSDR was interested in

improving outdoor air pollutant monitoring that it found insufficient to address the petition from
3

Senator DeWine. This interest led ATSDR to enlist the support of Response, Engineering, and

Analytical Contract (REAC) and Environmental Response Team Center (ERTC) to conduct air

dispersion modeling for Marietta air pollution sources. Due in part to Eramet’s large ongoing

TRI-reported Mn air emissions, its involvement in a lengthy history of complaints, and local Mn

air monitoring data that frequently exceeded ATSDR’s chronic inhalation Minimal Risk Level

for Mn (0.04 μg/m3), air dispersion modeling of Eramet’s Mn releases to air seemed a reasonable

starting point. One purpose of the modeling was to inform the siting process for additional air

monitors should they become available. ATSDR and U.S. EPA also discussed U.S. EPA’s use of

ATSDR’s modeling for the Ferroalloys Production residual risk test. 

Attachment 2 (an April 5, 2004 memorandum from Howard Schmidt (REAC) to Sella Burchette

(ERTC); see below) describes the air dispersion modeling and its results. The CALPUFF air

dispersion model was used to predict annual average Mn air concentrations in a 20 km square

grid centered on Eramet. As described in the first paragraph of Attachment 2, CALPUFF was

used primarily for its ability to better address complex terrain than models relying on steady-state

straight-line transport assumptions (i.e. the Industrial Source Complex [ISC] models). This

CALPUFF modeling used site-specific emissions, source characteristics and facility layout

information that came primarily from Eramet through Clean Air Act Section 114 Information

Requests. A receptor modeling grid schematic for the facility vicinity is shown in Attachment 2,

Figure 5. Hourly meteorological data from 1999 were obtained from the AMP-Ohio tower

depicted in Figure 6, with a windrose for those data displayed in Figure 7.

Clarifying information on air dispersion modeling approach, input and results is provided in

Attachments 4A, 4B, 5A and 5B below. These Attachments address technical questions that

arose after completion of the modeling that was conducted under contract.

3. Air dispersion modeling results

The CALPUFF model predicts a long term Mn concentration of ~ 1 μg/m3 at locations more than

a mile north of Eramet (Figure 1), corresponding to HQ = 20 (section 4, Table 1 below). On a

November 2004 visit to Marietta, a small neighborhood was observed on Township Road 125

approximately 1-2 miles N/NE of Eramet, verifying that residents live very close to or within the

1 μg/m3 Mn isopleth. Residences may also be present in or near the area of still higher off-site

concentrations (2-3 μg/m3) shown just north of and ~1/4 mile off-site. Table 1 indicates that

most (42 of 44) individuals living where modeled Mn ≥1 μg/m3

 are actually in areas where

modeled Mn ≥2 μg/m3

. 

4. Computing the Mn hazard quotient (HQ)

We assume that the residual risk test is satisfied if emissions from a facility in the source

category can be reasonably expected to result in an individual noncancer hazard greater than the

target-organ-specific hazard index (TOSHI) of 1.0. A TOSHI is the sum of the HQs of all

pollutants of concern that affect the same target organ. The HQ is a measured or modeled

estimate of a pollutant exposure divided by an exposure that is believed to be without appreciable

risk of adverse health effects. Given available information, it seemed reasonable to focus on 

deriving an inhalation HQ for Mn using Eramet emissions information and air dispersion
4

modeling. In the present case, no “TOSHI” other than the single HQ was derived.

We evaluated noncancer hazard by calculating the inhalation HQ for Mn in inhabited census

blocks, using 2000 Census data. Here, the HQ is equal to the model predicted annual average

Mn air concentration divided by the U.S. EPA inhalation Reference Concentration (RfC) for Mn

(0.05 μg/m3):

HQ = model predicted Mn air concentration (μg/m3) / RfC (μg/m3)

The use of the HQ below assumes that model-predicted annual average Mn concentrations are

reasonable surrogates for long term inhalation exposure concentrations. The Mn RfC is available

on U.S. EPA’s Integrated Risk Information System (IRIS) database (see

http://www.epa.gov/iris/subst/0373.htm), where its derivation, assumptions and limitations are

presented. As described in section I.A.2 of the IRIS Mn file, risk assessment for Mn needs to

consider both its nutritional essentiality (as an enzymatic cofactor; section I.A.4) and toxicity that

varies with exposure route, including potential olfactory bulb uptake (section I.B.4). The critical

effect for the inhalation RfC is neurobehavioral functional impairment (section I.B.1), assessed in

the Roels et al. (1992) critical study as decrements in visual reaction time, eye-hand coordination

and hand steadiness in exposed vs. control workers (section 1.B.2). The lack of adequate

reproductive and developmental toxicity information is discussed in section 1.B.5 of the IRIS Mn

file. The Mn RfC comprises an uncertainty factor of 1000: 10 for sensitive individuals;10 for

use of a LOAEL; and 10 for database limitations (less-than-chronic periods of exposure; lack of

developmental data; potential but unquantified differences in toxicity of different forms of Mn).

Neal Fann (OAQPS) overlayed modeled Mn concentrations with census data to generate the

results in Table 1 below. The analysis is described in a 5/4/04 memorandum from Neal Fann to

Margaret Sieffert and George Bollweg (Attachment 3).

TABLE 1. Estimated number of individuals exposed at various Mn HQs

(A)

Modeled annual average Mn

concentration (μg/m

3

)

(B)

Hazard Quotient

(C)

Cumulative Number of

Individuals Whose Hazard

Quotient is equal to or greater

than value in (B)

≥0.05 1 78,200

≥0.1 2 39,546

≥0.2 4 11,205

≥0.4 8 1,739

≥0.6 12 323

≥0.8 16 266

≥1 20 44

≥1.5 30 44

≥2 40 42
5

5. Mn air monitoring data

Ohio EPA has a metals air monitor located about 4.5 miles north-northeast of Eramet (shown as

a small flag, Attachment 2, Figures 1-4) at the Washington County Career Center. Monthly Mn

average concentrations based on every-six-day samples for Nov. 2000-Dec. 2004 are shown in

Figure 8. The monitored average Mn concentration for all monthly data points as of December

2004 is 0.19 ± 0.27 μg/m3 (mean ± standard deviation [SD]; n=50). The figure indicates that

about 75% (38 of 50) of monthly averages exceed the Mn RfC (0.05 μg/m3

). Note that the long

term modeled annual average Mn concentration at the monitoring location is 0.29 μg/m3

(Attachment 2, Discussion) based on 1998-2002 emissions information, in rough agreement with

the long term monitored value.

A second air monitor ~1/4 mi W/NW of the facility began operating in late 2004. Its initial

monthly data (n=3) show Mn concentrations = 0.53 ± 0.44 μg/m3 (mean ± SD).

6. Assumptions, limitations and uncertainties

(1) the present exercise focused on evaluating potential Mn inhalation exposure attributable to

one of two known U.S. Ferroalloys Production facilities (i.e. Eramet) in the Washington County,

OH vicinity. It excluded other routes of exposure, other pollutants emitted by Eramet (e.g.

chromium; mercury), and the potential for additional Mn exposure from the second facility;

(2) air dispersion modeling of estimated Mn emissions from Eramet may underestimate actual

near-source Mn air concentrations because fugitive air emissions (nearly 2/3 of Eramet’s 2002

TRI emission estimates) were largely excluded from the air dispersion modeling exercise; 

(3) HQs described above were derived by “overlaying” two geographic information sets

(modeled Mn air concentration estimates and year 2000 census data) to estimate Mn inhalation

exposure. This relies on the simplifying assumption that long term Mn inhalation exposure

concentration is the same as modeled Mn concentration. This assumption seems reasonable

given available air monitoring, modeling and historic (TRI) emissions release information; 

(4) a November 2004 site visit indicated that occupied residences are present between the Eramet

facility and the monitor at the Washington County Career Center. Mn air concentration is likely

higher at such residences than at this monitor due to their proximity to the emission source. 

Initial results from a second, near-facility monitor support this likelihood; 

(5) industrial point source air pollutant emitters other than Eramet are located in the study area,

raising the likelihood of additional air pollutant inhalation exposures for near-source residents; 

(6) despite scientific uncertainty regarding Mn inhalation toxicity at environmentally relevant

concentrations, use of the Mn RfC to derive HQs as in the present exercise represents current

practice for residual risk evaluation and seems reasonable.

Most of these considerations suggest that quantitative metrics in the current exercise

underestimate rather than overestimate near-source human exposure and risk from air pollutant

releases in the vicinity of Eramet.
6

Conclusion

The present analysis used (1) reasonable Mn emissions and source location data; (2) results from

a relevant dispersion modeling exercise; (3) the U.S. EPA Mn RfC as a reference value for

deriving an HQ; (4) 2000 Census information; and (5) available Mn air monitoring data. This

analysis supports the likelihood of long term Mn inhalation HQs greater than 1.0 for many

residents near the Eramet Marietta facility, with HQ>10 likely for several hundred residents. We

therefore cannot recommend eliminating the Ferroalloys Production source category from

consideration for a residual risk rule. We recommend instead that U.S. EPA pursue additional

relevant data, assessment and other analysis to address the results described above and the

potential for residual hazard/risk associated with the Ferroalloys Production source category.

[see Attachments and Figures below]
7

ATTACHMENTS AND FIGURES

Residual Risk Test for the Ferroalloys Production Source Category

Attachment 1 - Eramet Marietta facility schematic

Attachment 2 - Air dispersion modeling description and Figures; April 5, 2004 memorandum to

Sella Burchette from Howard Schmidt

• Figure 1 (Modeled annual average Mn ground-level air concentration near Eramet facility)

• Figure 1a (Modeled annual average Mn ground-level air concentration, Marietta OH vicinity)

• Figure 2 (Modeled annual average Mn dry deposition near Eramet) 

• Figure 3 (Modeled annual average Mn ground-level air concentration and topography, Marietta OH vicinity)

• Figure 4 (Annual average Mn dry deposition and topograpy, Marietta OH vicinity)

• Figure 5 (Receptor modeling grids and plotting domains, Marietta OH vicinity)

Figure 6 - AMP-Ohio (R.H. Gorsuch) weather tower/meteorlogical station

Figure 7 - Windrose for Marietta meteorologic data used in Eramet/ATSDR air dispersion

modeling

Figure 8 - Mn air concentrations monitored at Washington County (OH) Career Center near

Eramet-Marietta, Nov. 2000-Dec. 2004

Attachment 3 - Methods for estimating Marietta OH population exposure to airborne Mn; 

May 4, 2004 memorandum to George Bollweg and Margaret Sieffert from Neil Fann

Attachment 4A - Region 5 (R5) response to U.S. EPA internal review comments on 

Attachment 2 (Air dispersion modeling description; 5 April 2004 Memorandum to Sella

Burchette from Howard Schmidt)

Attachment 4B - Miscellaneous U.S. EPA internal review comments and R5 responses

pertaining to the June 9, 2004 Draft Residual Risk Test Memo

Attachments 5A (first reply) and 5B (second reply) - R5 questions and contractor responses to

R5 request for clarification of air dispersion modeling algorithms
8

ATTACHMENT 1 - Eramet Marietta Facility Schematic
9

ATTACHMENT 2

Air dispersion modeling description

DATE: 05 April 2004

TO: Sella Burchette, ERTC Work Assignment Manager

FROM: Howard Schmidt, REAC Senior Atmospheric Modeler

THROUGH: Jeff Bradstreet, REAC Air Group Leader

SUBJECT: Dispersion Modeling for Eramet Marietta, Inc., Marietta, OH

 3rd Revision

Dispersion modeling was performed to estimate the locations of potential manganese air and

ground-level impacts from daily operations at the Eramet Marietta, Inc. facility (“the facility”) in

Marietta, OH. The facility is located adjacent to the Ohio River in an area of complex terrain

where the Ohio River valley influences the dispersion of pollutants from the facility. CALPUFF

was chosen as the model for this exercise for its ability to handle this type of topographical

situation. The United States Environmental Protection Agency’s (U.S. EPA) Guideline on Air

Quality Models provides for the use of CALPUFF on a case-by-case basis for air quality

estimates involving complex meteorological flow conditions where steady-state straight-line

transport assumptions are inappropriate. This U.S. EPA standard is noted in the Federal Register

Volume 68, Number 72 dated 15 April 2003. 

Meteorological Data 

Data for this project was acquired from a variety of sources in order to supply the CALPUFF

model with ample and accurate surface, upper air, and precipitation information. Properly

formatted and representative data aids in the functionality of the model and the eventual

generation of potential impacts from the facility. 

Two surface data stations were used in this study. Hourly data from 1999 recorded by the

American Municipal Power – Ohio (AMP-Ohio) weather tower in Marietta, OH was provided to

the Response, Engineering, and Analytical Contract (REAC) by representatives from the Agency

for Toxic Substances and Disease Registry (ATSDR). According to information in a modeling

protocol from AMP-Ohio provided by ATSDR, the weather tower was located approximately 2.5

kilometers (km) north-northwest of the facility. Universal Transverse Mercator (UTM)

coordinates of the meteorological tower used in the study are (414700, 4317900). Data provided

by this weather tower included wind speed, wind direction, and ambient air temperature. 

In order to complete a modeling study, additional weather data (total sky cover, ceiling height,

dew point temperature, wet bulb temperature, station atmospheric pressure, and relative
10

humidity) was needed to supplement the weather data from the AMP-Ohio weather tower. Wet

bulb temperature was calculated for each hour based on a set of physical meteorological

equations. The remaining data was acquired for Parkersburg, WV through the Northeast

Regional Climate Center at Cornell University. This location was considered the closest and

most representative data for Marietta, OH. The Parkersburg, WV data was necessary to complete

a dataset in CD-144 format; acceptable for weather data used as input for the CALPUFF model. 

CALPUFF has the ability to accept weather data from multiple locations to enhance the ability of

the model to more accurately calculate results. In addition to the AMP-Ohio data, surface

weather observations from Wheeling, WV were added to the model. Data was obtained from the

website of the National Climatic Data Center (NCDC) for the year 1999. Similar to the AMPOhio, some manipulation was needed to put the data in a format suitable for input to CALPUFF.

Any missing or suspicious surface or upper air data was replaced using criteria set forth in the

U.S. EPA’s Procedures for Substituting Values for Missing NWS Meteorological Data for Use in

Regulatory Air Quality Models. 

An attempt was made to estimate the potential ground-level impacts from the operation of the

facility. Due to the lack of complete set of 1999 nearby hourly precipitation data, wet deposition

flux was not obtainable. The nearest complete set of precipitation data was found in Columbus,

OH and this was not adequate for the study. 

The nearest representative upper air data for 1999 was acquired for Pittsburgh, PA from an

online data source provided by the National Oceanic and Atmospheric Administration’s (NOAA)

Forecast Systems Laboratory (FSL). The data was obtained in original FSL rawinsonde format

that can be used by CALPUFF without any user formatting. 

Geophysical Data

Several types of geophysical data are required as input to CALPUFF. In general, a 20 x 20

kilometer (km) grid was produced with receptors placed every one km. The grid was offset in a

northerly direction from the source to enable more receptors to be located on the Ohio side of the

Ohio River. At each receptor, elevation, land use, and land cover data was provided to the

model. A second grid was produced to provide a finer mesh grid nearer the source. This grid was

centered on the source with receptors spaced every 200 meters (m) a distance of eight kilometers

in all directions. In addition, a flag icon has been placed on all grids to note the location of the

nearest state manganese monitor.

Digital Elevation Model (DEM) data was acquired from the United States Geological Survey

(USGS) website. The 1-degree Clarksburg-W.DEM used in CALPUFF corresponds to the 3-arcsecond (1:250,000 scale) USGS topographic map series that are available for all of the

contiguous United States and most of Alaska. The DEMs are expressed in geographic

coordinates (latitude and longitude) and most are referenced to the World Geodetic Survey

system of 1972 (WGS72). However, some are referenced to the WGS system of 1984 (WGS84).

The Clarksburg 1:250,000 scale Land Use and Land Cover (LULC) map was obtained from the

GeoCommunity’s GIS Data Depot. This series was compiled to portray the Level II categories of 
11

the LULC classification system. The Level II categories of this LULC classification system

provide the user with a basic framework to which third and fourth level categories may be added.

Modeling results are plotted on aerial photographs of the region nearby the facility. The Digital

Orthophoto Quadrangle Quarters (DOQQs) used in the figures are as follows:

TABLE 1. DOQQs Used in Study

ATSDR – Eramet

February 2004

 

Quadrangle Name Quadrant Year

Photographed

Fleming, OH NW 1994

Fleming, OH NE 1994

Fleming, OH SW 1994

Fleming, OH SE 1994

Marietta, OH NW 1996

Marietta, OH SW 1996

Parkersburg, WV NW 1996

Parkersburg, WV NE 1996

Parkersburg, WV SW 1996

Parkersburg, WV SE 1996

Valley Mills, WV NW 1996

Valley Mills, WV SW 1996

A georeferenced aerial photograph was used to identify the UTM coordinates for point sources

with missing data and to confirm the UTM locations of point sources used in the study provided

by Eramet to ATSDR. REAC personnel found that all UTM coordinates provided by Eramet

were erroneous to some degree and were changed up to 100 m to represent a correct UTM pair.

Source Characterization

Information used to characterize the numerous potential sources of manganese at the Eramet

facility was provided to REAC by ATSDR. Key documents include:

1. Response to Fourth Request to Provide Information Pursuant to the Clean Air Act,

Appendix B, Emission Inventory for Fee Emission Reporting, Eramet Marietta, Inc., date

13 July 2001

2. Response to Fifth Request to Provide Information Pursuant to the Clean Air Act,

Attachment A.1.a, Emissions Information; Attachment A.1.b, Stack Geographic

Coordinates; and Attachment C, Toxic Release Inventory Information, Eramet Marietta,

Inc., dated 11 June 2003

3. Response to Fifth Request to Provide Information Pursuant to the Clean Air Act,

Attachment C, Toxic Release Inventory Information, Eramet Marietta, Inc., 27 June 2003
12

A total of 65 processes are identified in key document 1 listed above. These processes were

narrowed down to those directly related to manganese and further narrowed down to those

having the greatest potential impact on the area nearby the facility. Subsequent to numerous

conversations with REAC Air Group Leader Jeffrey Bradstreet, Ph.D., twelve point sources were

eventually identified as having the greatest potential impact. The point sources were selected due

to the likelihood of the highest potential impact, while area sources were omitted due to their

very low emission rates and likelihood that any impacts would be within the boundaries of the

facility or very close to the fenceline. The point source processes chosen include:

· SP020BAG1 – Mn Metal Processing - Packing Dust Collector (including Ohio

EPA processes 158 through 162)

· SP020BAG2 – Mn Metal Processing - Ball Mill Dust Collector (includes Ohio

EPA processes 78 and 79)

· P025 – EM Briquetting System

· P026 – Mn Milling System – Ball Mill (includes Ohio EPA process 114)

· P901SCR – Furnace #1 (SiMn) Melting - Wet Scrubber

· P901BAG – Furnace #1 (SiMn) Melting – Taphole Baghouse

· P908 – Furnace #12 (FeMn)

· P909 – Furnace #18 (FeMn)

· P909 – Furnace #18 (four draft stacks)

Emission rate calculations are derived from five years of data covering 1998 through 2002

provided to REAC from ATSDR. Table 2, Average PM10 Emission Rate Calculations, is

presented as the initial step in arriving at a manganese emission rate for each point source

process. The calculation of average manganese emission rates and all source parameters for each

point source process is presented in Table 3, Eramet Manganese Point Source Emission Data.
13

TABLE 2. Average PM10 Emission Rate Calculations

ATSDR – Eramet

February 2004

 Emission Rate (ton/yr)

Point Source Name 1998 1999 2000 2001 2002 Avg 98-02

P020 Mn Metal Processinga 0.34 0.42 0.33 0 0 0.36

 SP020TOTAL - Packing and Ball Mill

b 0.13 0.16 0.13 0 0 0.14

 SP020BAG1 - Packing Dust Collectorc 0.08 0.10 0.08 0 0 0.09

 SP020BAG2 - Ball Mill Dust Collectorc 0.05 0.06 0.05 0 0 0.05

P025 "EM" Briquetting System 0.13 0.12 0.09 0.12 0.12 0.12

P026 Mn Milling system 0.203 0.146 0.122 0.129 0.134 0.15

P901 Furnace #1 (SiMn) 158.34 286.76 256.95 218.76 199.36 224.03

 P901SCR Furnace #1Wet Scrubberd 109.57 198.44 177.81 151.38 137.96 155.03

 P901BAG Furnace #1Taphole Baghoused 48.77 88.32 79.14 67.38 61.40 69.00

P908 Furnace #12 (FeMn) 35.49 82.91 95.64 82.95 65.41 72.48

P909 Furnace #18 (FeMn) 108.77 111.31 103.73 114.06 102.09 107.99

a: Process ceased 10/00, averages based on 1998 - 2000 data

b: PM from P020 attributed to packing dust collector and ball mill collector - ratio based on emission report from 2000

c: PM from SP020TOTAL attributed to individual process - ratio based on emission inventory report from 2000

d: PM from P901 attributed to individual process - ratio based on emission inventory report from 2000
14

TABLE 3. Eramet Manganese Point Source Emission Data

ATSDR – Eramet

February 2004

Avg PM10 Avg PM10 Avg Mn 

Emis Rate Emis Rate Emis Rate Flow Exit Stack Stack Stack Stack Gas Gas

Point Source Name x y 1998-2002i 1998-2002 1998-2002b Rate Vel Dia Dia Ht Ht Temp Temp

utmc utmc

ton/yr g/s g/s acfm m/s ft

f,g m ft m Deg F Deg K

P020 Mn Metal Processinga

 SP020BAG1 - Packing Dust Collectord 455196 4358382 0.09 0.003 0.001 6,500 10.51 2.00 0.61 50 15.24 77 354

 SP020BAG2 - Ball Mill Dust Collectore 455141 4358364 0.05 0.001 0.001 15,000 20.23 2.19 0.67 54 16.46 165 512.4

P025 "EM" Briquetting System 454680 4358258 0.12 0.003 0.002 9,825 11.13 2.39 0.73 38 11.58 77 354

P026 Mn Milling system 454746 4358313 0.15 0.004 0.002 25 0.03 2.19 0.67 6 1.83 77 354.0

P901 Furnace #1 (SiMn)

 P901SCR Furnace #1Wet Scrubber 455178 4358022 155.03 4.496 2.023 137,000 13.85 8.00 2.44 123 37.49 140 467.4

 P901BAG Furnace #1Taphole Baghouse 455112 4358000 69.00 2.001 0.900 75,000 21.77 4.72 1.44 96 29.26 120 431.4

P908 Furnace #12 (FeMn) 454726 4357895 72.48 2.102 0.946 169,500 17.13 8.00 2.44 123 37.49 140 467.4

P909 Furnace #18 (FeMn)h 454446 4357749 107.99 3.132 1.409 10,500 25.56 1.63 0.50 110 33.53 105 404.4

 P909NEDR Furnace #18 NE draft stackh 454483 4357759 71.2 2.065 0.929 29,568 8.37 4.78 1.46 110 33.53 85 368.4

 P909NWDR Furnace #18 NW draft stackh 454441 4357750 71.2 2.065 0.929 33,104 9.37 4.78 1.46 110 33.53 85 368.4

 P909SEDR Furnace #18 SE draft stackh 454486 4357747 71.2 2.065 0.929 36,893 11.28 4.60 1.40 110 33.53 85 368.4

 P909SWDR Furnace #18 SW draft stackh 454455 4357738 71.2 2.065 0.929 39,070 11.94 4.60 1.40 110 33.53 85 368.4

a: Process ceased 10/00, averages based on 1998 - 2000 data

b: Mn emissiom rate based on 45% grade ore

c: Inaccurate UTMs provided by Eramet; estimated locations based on Eramet autocad drawing and ArcView georeferenced map

d: Includes OEPA subprocesses 158 through 162

e: Includes OEPA subprocesses 78 & 79

f: Release characteristic given as 4.5 ft2 - converted to an equivalent circular diameter via d=2*(4.5/pi)1/2

g: No stack diameter provided, ball mill dust collector diameter from SP020BAG used

h: Corrected information for draft stack flow rates from 2003 testing provided separately to REAC from ATSDR

I: Emission rate for P909 draft stacks taken from 2000 Ohio EPA Emission Inventory for Fee Emission Reporting

Discussion

Figure 1 presents average annual manganese ground-level air concentrations nearby the Eramet

facility. Maximum values in excess of 6.00 μg/m3are located with the 3.00 μg/m3isopleth

located on the facility with an axis of higher concentrations extending almost due north of the

site. Figure 1a utilizes the same data as Figure 1, but is represented on a different scale to

include the critical 0.05 μg/m3value that represents the Reference Concentration (RfC) for

manganese. Figure 2 presents annual average manganese dry deposition values nearby the

Eramet facility. Maximum values in excess of 40,000 μg/m2/yr are noted on the facility with

isopleths extending northeast of the facility. A sharper gradient and decrease in values is noted

south and west of the facility. Figures 3 and 4 demonstrate the effect of topography on the release
15

of contaminants from the Eramet facility. Brighter shades of white represent relatively higher

elevations and darker colors represent relatively lower elevations. In both the air concentration

and deposition cases, contours extend almost due north through an area of relatively lower

elevation with higher points both to the east and west. Figure 5 is a visual of the two plotting

domains used in the study. The rectangular grid extends 20 km in each direction from its center

with each gridpoint represented by a flag on the figure. The tight cluster of flags represents the

finer grid employed around the source to better represent the effects of topography.

A red flag on each figure represents the location of an air monitor on State Route 676 with a

UTM pair of (456755, 4365021). A request was made by ATSDR to provide the average

manganese air concentration and deposition at this location. Average manganese air

concentration at the monitor is 0.29 μg/m3and deposition at the monitor is 2567 μg/m2/yr.
16

Figure 1
17

Figure 1a
18

Figure 2
19

Figure 3
20

Figure 4
21

Figure 5
22

Figure 6

Location of AMP-Ohio (R.H. Gorsuch) meteorological station/weather tower (red flag

 ~2.5 km north-northwest of Eramet Marietta facility), near Marietta OH
23

Figure 7

Windrose for Marietta meteorologic data used in Eramet/ATSDR air dispersion modeling
24

Figure 8

Mn air concentrations monitored at Washington County (OH) Career Center,

November 2000 - December 2004
25

ATTACHMENT 3

Date: May 4, 2004

To: George Bollweg, Margaret Sieffert

From: Neal Fann

Re: Methods for estimating Marietta OH population exposure to airborne Mn

Overview

To estimate the cumulative number of individuals exposed at each level of risk, I used a Geographical Information

System (GIS) to estimate the concentrations of manganese at the census block centroids within the 20x20 kilometer

modeling area of the Eramet facility. The receptor grid did not match the centroids of the census blocks; this made it

necessary to estimate block concentration by associating each block centroid with the nearest modeling receptor.

Methodology

EPA typically uses census block centroids (that is, the geographic center of the census block) as modeling receptors to

estimate population exposure; the centroids represent the finest resolution of population distribution in the modeling

radius. However, the Eramet CalPuff modeling grid did not match the location of the block centroids, making it necessary

to estimate block concentrations. To do this, I used ArcGIS 8 to “spatially join” each census block centroid with the

nearest receptor point.

My specific steps were as follows:

1. Calculate the locations of the census block centroids within the modeling area. The US census bureau does

not provide the geographic centroids of census blocks and users must use a GIS to calculate these coordinates.

2. Create a “spatial join” between the block centroids and the modeling grid. This procedure joins each block

centroid (and its corresponding population data) with the closest receptor (and its modeled estimate of

manganese for that receptor location).

3. Eliminate block centroids that are further than 100 meters from the modeling radius. The spatial join

procedure joins each block centroid in the GIS with a receptor, irrespective of distance. Eliminating blocks

that are further than 100 meters from the nearest receptor point ensures that the GIS only provides ambient

concentrations of manganese at census blocks within the modeling domain (approximately 40km).

4. Calculate population exposure. Using a spreadsheet, I calculated the cumulative number of individuals

exposed at each level of risk. Specifically, I used the “SUMIF” function in MS Excel to calculate the

cumulative number of individuals exposed at varying levels of manganese concentration.

1

In the absence of a modeling grid that exactly matches the locations of the census block centroids, this method is the most

accurate method that is readily available.

Sources of Input Data

· Model Receptors. The ATSDR contractor supplied me with the modeling receptors from the CalPuff

modeling runs.

· Census Data. I downloaded this data from the census bureau (www.census.gov) and calculated the

locations of the census block centroids in ArcGIS.

· Software. I used ArcGIS 8.3 for all GIS work and MS Excel 2002 for all calculations.

1

See attached spreadsheet in file Mn Ambient Data.xls for calculations.
26

ATTACHMENT 4A

Region 5 (R5) response to U.S. EPAinternal review comments on Attachment 2 (Air dispersion

modeling description; 5 April 2004 Memorandum from Howard Schmidt to Sella Burchette)

Purpose of this Attachment

U.S. EPA’s internal review of the June 9, 2004 Draft Residual Risk Test for the Ferroalloys

Production Source Category (“risk test memo”) suggested the need for elaboration and clarification

of several aspects of the air dispersion modeling description (Attachment 2). Because Attachment

2 is part of a completed contract entered into by the Agency for Toxic Substances and Disease

Registry(ATSDR), its technical analysis is also complete and not open to modification. The purpose

of Attachment 4A is to respond to U.S. EPA’s internal review comments (numbered below) and

provide the needed elaboration/clarification to support Attachment 2's usabilityin the risk test memo.

1. Reasons for and advantages of using CALPUFF rather than some other model for air

dispersion modeling of Eramet Marietta’s Mn air emissions

R5 response: the first paragraph of Attachment 2 (quoted below) provides rationale for CALPUFF

use for purposes of the risk test memo. Themention of “straight-line transport assumptions” is likely

to refer to assumptions in the Industrial Source Complex (ISC) model that seem inconsistent with

the terrain in the vicinity of Eramet and support the use of CALPUFF as an alternative:

“Dispersion modeling was performed to estimate the locations of potential manganese air and

ground-level impacts from daily operations at the Eramet Marietta, Inc. facility (“the facility”) in

Marietta, OH. The facility is located adjacent to the Ohio River in an area of complex terrain where

the Ohio River valley influences the dispersion of pollutants from the facility. CALPUFF was

chosen as the model for this exercise for its ability to handle this type of topographical situation. The

United States Environmental Protection Agency’s (U.S. EPA) Guideline on Air Quality Models

provides for the use of CALPUFF on a case-by-case basis for air quality estimates involving

complex meteorological flow conditions where steady-state straight-line transport assumptions are

inappropriate. This U.S. EPA standard is noted in the Federal Register Volume 68, Number 72

dated 15 April 2003.”

2. Response to U.S. EPA internal review questions:

• Why were only 1999 met data used? 

• Isn’t it preferable to use met data averaged over the same time period as the emissions

data? 

R5 response: currently, the standard procedure as detailed in the Guideline on Air Quality Models

is to use either a) the most recent five years of data from the most representative/closest National

Weather Service station (generally at an airport) or b) one year of onsite meteorological data. The

latter option is preferable if onsite data is available, as it would be the most representative of the
27

actual conditions at the site. This approach assumes that in any 5 year period at a representative site,

or any one-year period onsite, one is likely to see most every possible type of meteorological

condition that could reasonably be expected at the location in question; thus, the year of the data is

of little consequence unless there is certain knowledge a substantial meteorological anomaly

occurred during the one-year or five-year measurement period. While this has been the stance taken

most often in the recent past, there are currently ongoing discussions regarding the use of mesoscale

meteorological data for complex wind and/or long-range transport issues. However, one year of site

specific meteorological data is adequate for this type of modeling, based on currently accepted

procedures. 

3. ORD-6/22/04 comment (from Katie Warwick) on June 9, 2004 draft risk test memo,

Attachment 2: Attachment 2 - Geophysical Data - Please refer to the predominant wind direction

as to the reason why there are more receptors in Ohio.

R5 response: Jennifer Freed (ATSDR) addressed this during the June 23, 2004 Workgroup call. The

receptor grid surrounding the facilitywas offset to include the maximum impact area and thus ensure

that the modeling results include the areas of highest concentration. For stack emissions, the

maximum impact area is often most influenced by the predominant wind direction, which for this

location is from the south. Additionally, it was done to ensure that the receptor grid include the

location of the monitor site, which is located to the north of the facility. Thus, the receptor

distribution that was used was chosen to address the predominant wind direction (from the south);

to include the area of highest likely Mn air concentrations and deposition; and to include the

monitoring site location. 

4. Provide algorithms used to derive emission rates in Tables 2 and 3 in Attachment 2

R5 response: the algorithms are available in the Excel spreadsheet “Eramet Mn Source Data”

(attached separately): the “Avg Emis Rate” tab contains Table 2; the “Point Source Data” tab

contains Table 3. Because ATSDR’s contract with their modeler was complete, we were unable to

comprehensively question all input to the algorithms. Within the constraints of our limited access

to the modeler, we did ask several questions regarding the basis for these estimates (see

Attachments 5A and 5B) and we did receive responses. Although a few of the modelers’ responses

are unclear and/or inaccurate (e.g. the 1/24/05 reply that begins “A second request was submitted by

EPA Ohio...” [this is incorrect; the request was submitted by R5]), many assumptions may follow

from the overall modeling objectives (assessing ground level air concentrations downwind from the

facility, not necessarily close to the facility boundary; e.g. fugitive emissions exclusion) and

ATSDR’sinterest in siting air monitors. Although U.S. EPA’s interest includes nearby residents as

well as those further downwind, the modeling showssubstantial potential hazard in inhabited areas.

5. Comment from 6/22/04 ORD/Katie Warwick written comments:

p. 4 - Monitoring Data - We are unclear about what the modeled concentration represents -- a five

year average, corresponding to the monitor period? Or something else? We suggest providing a plot

which shows the Mn monitor concentration over time. This would convey the variability of

concentration relative to the long-term average.
28

R5 response: the comment addresses air monitoring data and its presentation, and air dispersion

modeling estimates. The air monitoring data have been plotted assuggested and are now presented

as Figure 8 (replacing the concentration table in Section 4, Results and discussion).

The modeling data represents the annual average concentrations based on one year of on-site

meteorological data for calendar year 1999 and an averaged emission rate from the five year period

spanning 1998-2002. The period of the meteorological data falls within the period of the emissions

data; however, this is not required for a modeling study. Without explicitly asking the modeling

contractor why the meteorological data was chosen, one can assume that the 1999 was the only year,

or the most recent year, that onsite data was available. The 1998-2002 emissions data is what was

reported by the Eramet in response to a request for information from U.S. EPA. The average was

used (rather than the worst-case emissions year, or the most recent year, etc.) because of the interest

in the chronic nature of the exposure in question. An average is a better representation of the type

of exposure expected over a longer time frame than a single year.

The monitoring data currently represent 50 months (November 2000 - December 2004) of everysix-day sampling. Although there is not exact correspondence between the time period of the

emissions data used for air dispersion modeling and the time period of the air monitoring data, there

is overlap (2000-2002). For purposes of residual risk assessment, both air dispersion modeling

estimates and air monitoring measurements are used here to inform the issue of potential human

exposure to industrial air pollution - in the present case, to Eramet’s air releases of Mn. As requested

in the comment, we replaced the tabular presentation of Mn air concentrations with Figure 8.
29

ATTACHMENT 4B

Miscellaneous U.S. EPA internal review comments and R5 responses regarding June 9, 2004

Draft Residual Risk Test Memo

1. Ann Johnson (OPEI) 7/8/04 written comments: “...it would be nice to get a table of the 65

processes, the emissions from those processes, and their distances from the fenceline...” Ann also

asked during the 6/23/04 call if we have Mn emissions estimates for all 65 processes. [note: 65

processes arementioned in Attachment 2, Source Characterization, item 3, as the overall group from

which a subset of 12 were chosen for Mn air dispersion modeling.]

R5 response: All of the 65 processes are listed at the end of this attachment, 45 of which are called

“insignificant”. USEPA Region 5 does not have emissions and distance-to-fenceline information

for all these sources, and obtaining this information would involve substantial additional work. 

ATSDR’s modeling contractor asserted that “those [emission sources] having the greatest potential

impact on the area nearby the facility” were considered in their modeling exercise. Although a

comprehensive emissions evaluation seems appropriate for a refined assessment, the HQ=1 was

convincingly exceeded based on ATSDR’s analysis that focused on the selected subset of Mn

emission sources. Including more sources could lead to a bigger HQ but wouldn’t change the

conclusion of the risk test memo, reducing the need for comprehensive emissions characterization

for present purposes.

2. Provide algorithms used to derive emission rates in Tables 2 and 3 in Attachment 2
30

R5 response: The algorithms are available in the Excel spreadsheet “Eramet Mn Source Data”

(attached separately): the “Avg Emis Rate” tab contains Table 2; the “Point Source Data” tab

contains Table 3. 
31

In reviewing the emission estimates of Attachment 2, Tables 2 and 3, R5 directed several questions

to ATSDR’s modeling contractor (see Attachments 5A and 5B). Our review of these responses

indicates that values in Tables 2 and 3 are reasonable if one accepts the modeling objectives and

judgments of the modeler. Emission reports cited in Table 2 footnotes were reviewed and extracted

values were verified. However, ATSDR’s modeling objectives led the modelers to exclude

processes that might be relevant for estimation of near-source concentrations. 

For example, the first row of Table 2 (“P020 Mn Metal Processing”) lists an average 1998-2002

estimate of 0.36 tons/year from this overall process. The second row of Table 2 (“SP020 TOTAL -

Packing and Ball Mill”) gives a 0.14 tons/year average for 1998-2002, comprised of two

subprocesses(0.09 and 0.05 tons/year) that were actually carried forward into Table 3 and modeled.

Thus, of the 0.36 tons/year emitted from the overall process only 0.14/0.36 or about 39% was

included in the dispersion model. Other exclusions resulting from the modeling objectives and

modeler’sjudgments could lead to potential underestimates of long term concentrations closer in to

the facility.

3. ORD-6/22/04 Katie Warwick written comments: “...Below are some comments from the ORD staff on the

draft Residual Risk Test for the Ferroalloys Production Source Category, dated June 9, 2004. We appreciate having

the opportunity to review this draft document. In general, the memorandum is well written, concise, and clear. However,

we recommend that the memo provide more detail about your next steps, i.e., what type of data will you pursue, what

sources will you look at, what pollutants will you examine, etc.

R5 response: We believe the “next steps” discussion is outside the scope of the risk test memo, the

purpose of which is to determine whether the source category can be shown at the outset not to

require a residual risk rule on the basis of data already in U.S. EPA’s possession and a relatively

simple and health-protective analysis. We agree that a “brainstorming” session regarding next steps

should occur after the risk test memo is completed.

4. p. 9 - Attachment 2 - Table 1 -- How has the vicinity changed since those dates [1994; 1996] - e.g., major

development, residences, etc.?

R5 response: census data (2000) are the most recent available and were used for risk test memo

purposes. A November 2004 visit to Marietta OH verified that homes/residences are present within

a mile or two N and NE of Eramet although the immediate area appears sparsely populated. During

our November 2004 visit we heard anecdotal discussion of the potential for increasing development

along State Route 7 near Eramet that may accompany recent improvements to that highway.

5. p. 19 - Attachment 3 -- Overview - last sentence -- Why was the concentration assigned to nearest receptor rather than

interpolating to the centroid?...”

R5 Response: Neal Fann OAQPS-REAG) response: “I assigned concentrations from the receptor

grid to the nearest census block centroid because the distance between the two was uniformly

minuscule (on the order of a few meters, at most).”

6. Scott Jenkins (OAQPS-REAG): risk test memo needs more detail in its description of the Mn

emission rates. Show calculations, provide more info on dry deposition (is this information is

available from model input files?).
32

R5 Response: More detail on emission rate issues is provided in Attachments 4A, 5A and 5B. With

regard to dry deposition: even the present restricted scope (potential inhalation exposure only)

showed HQs substantially greater than 1.0, reducing (we believe) the need for either a broader or

more in-depth scope in the residual risk test memo. The deposition information was included for

completeness and without comment as part of the April 5, 2004 air dispersion modeling

memorandum (Attachment 2). We agree that wet and dry deposition are relevant concerns for a

refined risk assessment.
33

65 processes list requested in Attachment 4B, Comment 1

The following processes are listed in Eramet’s permit (from OhioEPA Final Title V Permit, issue

date 12/18/02; effective date 1/08/02; expiration date 12/18/07). This information was requested in

comments of the Ferroalloys Production workgroup (“...it would be nice to get a table of the 65

processes, the emissions from those processes, and their distances from the fenceline...”). 

“Emissions Unit ID (Company ID)/Emissions Unit Activity Description

1. B005 (Grizzly Generator) - Diesel generator for grizzly sizing operation

2. F001 (Roads & Parking Areas) - Plant wide roadways and parking areas

3. F002 (Storage Piles) - Plant wide storage piles

4. F007 (Furnace 1 Casting) - Furnace #1 casting

5. F008 (Furnace 12 Casting) - Furnace #12 casting

6. F009 (Furnace 18 Casting) - Furnace #18 casting

7. F010 (Grizzly Sizing) - Grizzly sizing operation

8. F012 (Met Oxy Red Process) - Metal Oxygen Reduction process

9. F013 (Raw Mat - Bldg. 52) - Building 52 crusher

10. F014 (C7P Crush Sys 3 & 4) - C7P Systems #3 & #4. Crushing, sizing and packing of material

11. F016 (Metal Powders) - Fine sizing and impactor (systems #5 & #6) for metal powders

12. F017 (Simplex Systems) - Simplex mix, milling, furnace and packing system

13. P018 (Vacuum Furnace 50) - Vacuum Furnace #50

14. P020 (Mang Metal Process) - Elect[r]olytic manganese production

15. P022 (Chrome Metal Process) - Elect[r]olytic chrommium production

16. P025 (EM Briquetting) - EM briquetting system

17. P901 (#1 Furnace) - Submerged Arc Furnace

18. P908 (#12 Furnace) - Submerged Arc Furnace

19. P909 (#18 Furnace) - Submerged Arc Fur[na]ce

20. Z911 (C2PAlloy Crushing and Sizing) - C2P alloy crushing”

From p. 11, Title V Final Permit, Specific Facility Terms and Conditions; State Only Enforceable Section:

“The following insignificant emissions units are located at this facility:

1. F003 - barge unloading;

2. F015 - acid waste treatment;

3. P026 - manganese milling;

4. P912 - C7P bagger;

5. P913 - MOR pelletizer;

6. P914 - electrolytic manganese flake packaging;

7. Z001 - chill spray prep;

8. Z504 - furnace 1 hot metal;

9. Z517 - lab equipment and hoods;

10. Z518 - refrigerant reclaim & recycle;

11. Z519 - 15,000-gallon diesel tank;

12. Z520 - 6,000-gallon diesel tank;

13. Z521 - refractory mix & apply;

14. Z522 - used ladle repair;

15. Z523 - new ladle prep;

16. Z524 - gunite mix & application;

17. Z525 - pigging conveyor;

18. Z526 - ladle preheat operation;

19. Z527 - simplex parts cleaner 1;

20. Z528 - electrolytic chrome parts cleaner 1;
34

21. Z529 - locomotive shop hydraulic parts cleaner;

22. Z530 - electric shop parts cleaner;

23. Z531 - locomotive shop parts cleaner 1;

24. Z532 - locomotive shop parts cleaner 2;

25. Z533 - machine shop parts cleaner;

26. Z534 - C3F shop parts cleaner;

27. Z535 - electrolytic chromium shop parts cleaner 2;

28. Z536 - electrolytic manganese shop parts cleaner;

29. Z537 - C1F shop parts cleaner;

30. Z538 - south side shop parts cleaner;

31. Z539 - simplex shop parts cleaner 2;

32. Z540 - locomotive shop parts cleaner 3;

33. Z904 - raw materials mix house;

34. Z905 - C7P crush/size system 1;

35. Z906 - C7P crush/size system 2;

36. Z910 - sulfur burning;

37. Z912 - furnace 1 slag handling;

38. Z913 - furnace 1 feed system;

39. Z914 - furnace 12 hot metal;

40. Z915 - furnace 12 slag handling;

41. Z916 - furnace 12 feed system;

42. Z917 - furnace 18 hot metal;

43. Z918 - furnace 18 slag handling;

44. Z919 - furnace 18 feed system; and

45. Z921 - C2P picking conveyor.”
35

ATTACHMENT 5A

R5 questions and contractor response to R5 request for clarification of air dispersion modeling

algorithms

First reply 

To: Michelle Colledge, ATSDR Region V

From: Howard Schmidt, Lockheed Martin/REAC Senior Atmospheric Modeler

Through: Sella Burchette, EPA/ERT Work Assignment Manager

Subject: Response to EPA questions on Final Atmospheric Modeling Report

Eramet Marietta, Marietta, OH

1. How were 65 processes identified in “key document 1” narrowed to 12 (nine of which are listed in bullet

points under “Source Characterization”)? Although “numerous conversations” in this narrowing process are

described, few details are given, reducing transparency of a central part of the quantitative estimates.

The understood objective of the modeling exercise was to assess the potential ground level

ambient air quality impact of manganese related emissions off site. Therefore the approach

taken was to evaluate the processesfor 1) emissions, 2) emissions of manganese compounds and

3) emissions that would impact off site. 

The first step was to eliminate those processes for which no or negligible emissions were

reported. As noted in the April 5, 2004 memorandum describing the modeling exercise, the

potentialsources were next reviewed for manganese in the process. If a process did not involve

manganese, such as the Cummins Diesel Generator (B005), it was eliminated from further

consideration. At this point the field of possible sources was now narrowed to 28. 

Experience has shown that low level emissions, fugitive and those emitted from ground level to

roof vent level, would not have significant impacts off site. Therefore the low level releases

were eliminated fromfurther consideration. Thisstep reduced the field of sources to be modeled

to 12. (REPLY FROM JEFF BRADSTREET, Lockheed Martin/REAC Air Response

Section Leader)

2. Table 2: how were ratios 0.382, 0.631, and 0.369 derived for rows 6-8, e.g. for the year 2000 (Column

D)? Same question, P901 Furnace#1 – how were ratios 0.692 and 0.308 derived for rows 15 and 16?

The Mn Metal Processing (P020) is a complex process. Only particular portions of that process

were assessed to be potentially contributory to Mn emissions outside the fenceline of Eramet. 

The Packing and Ball Mill process was identified as the portion of P020 that would fit the

criteria for being included as a Mn source. Additionally, as the Packing and Ball Mill portions

of P020 have different source characteristics, they were modeled separately and their

contribution to the overall P020 processratioed. Thisis spelled out in the spreadsheet and noted

in footnote b.
36

Similarly, P901 was broken down into Wet Scrubber and Taphole Baghouse and their individual

contributions were proportionally identified. 

The MS Excel worksheet Point Source Data shows that the main process themselves were not

modeled (P020, P901 Furnace #1), but only portions that met the modeling criteria were

identified and included. (REPLY FROM HOWARD SCHMIDT, Lockheed Martin/REAC

Senior Atmospheric Modeler)

3. Why were air emissionsfor P020 Mn Metal Processing (ceased operation in 2000) included for dispersion

modeling, while those for the operating manganese oxygen refining process (MOR) were not? Also,

knowing that the tapping emissions from the #18 furnace are ducted to the same baghouse as the MOR

emissions, how were the #18 furnace tapping emissions accounted for in the modeling.

The P020 Mn Metal processing was included because the information provided showed that it

had manganese related emissions for two of the five meteorological years modeled. Emissions

from this source were only included for those years that it did operate. 

The information provided on the P010 MOR process indicated that it was primarily a fugitive

source, emission were release from essentially ground level. These fugitive emissions would

not significantly impact off site, as stated above, and were therefore not included. The bag

house emissions were evidently emitted from a roof top vent as no stack information was

provided for this source. Roof top vent emissions would also not significantly impact off the

site and therefore were not included. (REPLY FROM JEFF BRADSTREET, Lockheed

Martin/REAC Air Response Section Leader)

4. How was the particle size information and reactivity for the dispersion modeling chosen? Were these

numbers source specific or some kind of default value? If default, isthere any indication that these numbers

are in any way representative of the particles emitted by Eramet?

The values for particle size and reactivity were defaults found in CALPUFF. There was no

evidence in the documentation that any previous engineering study had been completed to

provide this information and the budget to complete this project would not have allowed forsuch

a study to be completed. For the same reason, a sensitivity analysis with varying particle sizes

and reactivity values to assess possible differences in location and magnitude of impact was not

completed. (REPLY FROM HOWARD SCHMIDT, Lockheed Martin/REAC Senior

Atmospheric Modeler)

5. Why was the average emission rate from 1998 – 2002 used in the modeling rather than the highest of the

five years? Was this to represent the long-term chronic average rather than the highest worst-case year, or

for some other reason?

Average emission rates for the period 1998 – 2002 were chosen to represent long-term chronic

effects. (REPLY FROM JENNIFER FREED, ATSDR LT/US Public Health Service and

HOWARD SCHMIDT, Lockheed Martin/REAC Senior Atmospheric Modeler)
37

ATTACHMENT 5B

R5 questions and contractor response to R5 request for clarification of air dispersion modeling

algorithms

Second reply

DATE: January 24, 2005

TO: Michelle Colledge, ATSDR Region V

THROUGH: Sella Burchette, ERT Work Assignment Manager

FROM: Howard Schmidt, Lockheed Martin/REAC Atmospheric Modeling Team Leader

SUBJECT: Clarification of Certain Calculations for Modeling from Eramet Marietta

A second request was submitted by EPA Ohio through U.S. EPA Region V and EPA/ERT to provide a

clarification in the arrival of particular calculations used in the atmospheric modeling study for Eramet

Marietta. EPA Ohio questions the use of “ratios” in the spreadsheets detailing the emission rates for

processes P020, Mn Metal Processing and P901, Furnace #1. Looking back, I probably should not have

included the second worksheet within the Microsoft Excel spreadsheet titled AVG EMIS RATE as it has

caused confusion. My original intention was for that spreadsheet to provide clarity, which apparently it has

not. I will address the specific question forward to me in an email dated January 14, 2005.

In general terms, the number used in row 6 of the table in question (0.382) is not a ratio, but simply shows

the percentage that Packing & Ball Mill processes contribute to the overall P020 process. Similarly, the

numbers shown in rows 7 & 8 are the percentages that the Packing Process and Ball Mill Process contribute

to the overall Packing/Ball Mill processes. 

I will explain the complete process in detail.

1. Emission rates in ton/yr for process P020 were obtained for the years 1998 through 2000 from the 5th

CAA Information Request, Attachment B, Emission Rates. The average for the three years was 0.36 tons/yr.

2. Through decisions made by AirResponse Section LeaderJeffrey Bradstreet, theBall Mill DustCollector

& Packing Dust Collector was deemed as significant contributors to process P020. Subprocesses 078 & 079

were chosen for the Ball Mill Dust Collector and subprocesses 158 through 162 were chosen for the Packing

Dust Collector. The previous decision was taken from information provided in the 5th CAA Information

Request, Attachment B, 2000 Emission Fee Reporting.

3. The emission subprocesses are only provided for the year 2000 from the above mentioned document. 

However, this information is vital in determining the portions of each main process responsible for PM10

emissions. The documentation shows that Subprocesses 078 & 079 totaled .05 tons for the year 2000 and

Subprocesses 158 through 162 totaled .08 tons for the year 2000 for a total of 0.13 tons – or – 38.2% of the

total emissions from P020 for the year 2000. Individually, the subprocesses represent 36.9% and 63.1%.
38

4. These percentages were then assumed to apply for the years 1998 and 1999, where only the total PM10

emission rate for P020 was available. Without this assumption and breaking down of the processes,

modeling would not have been possible. 

5. The final step was to calculate the amount of Mn within the PM10 emissions. This information was not

provided in the documentation. Therefore, industry documentation was obtained from the internet that

showed manganese ore to be approximately 45% Mn http://www.orissamining.com/mangan.htm

6. Multiplying the PM10 emissions by 0.45 provided actual Mn emissions that were used as input for the

model.

I hope this detailed explanation will suffice in providing evidence as to how emission rates were calculated

for several processes modeled for Eramet Marietta.

There is also brief mention in the email of January 14, 2005 about question #3 from the document sent from

Lockheed Martin/REAC on December 29, 2004 pertaining to the choice of processes used in the modeling

study and those not included. All I can add is that this was not an objective exercise, but rather subjective. 

In the expert opinion of our environmental engineer the processes felt to have the greatest potential impact

to off-site receptors were included in the modeling study; those which were negligible or deemed to pose

only a potential threat to on-site interests were omitted.