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On May 22, 2000, the Agency for Toxic Substances and Disease Registry (ATSDR) was petitionedby United States Senator Mike DeWine (Ohio) to evaluate the health impacts from air pollution onresidents of Marietta, Washington County, Ohio [1]. However, at that time, data were insufficientto address the petition.

In March 2002, ATSDR staff met with concerned residents about their health concerns andexposure to emissions from a nearby industrial complex. Located several miles outside the Cityof Marietta, Ohio, a former Union Carbide facility complex is currently occupied by fourcompanies including: Eramet Marietta, Inc. (EMI), Eveready Battery, Solvay AdvancedPolymers, and Chevron-Phillips Chemical Company. American Municipal Power (AMP) Ohio,originally built to provide power to Union Carbide, is located across the street from the complex.There is a residential area to the north of the facility. The predominant wind direction in the areais to the northeast. The City of Marietta is located 4 miles northeast of the facility, or"downwind" (see Appendix A). The residents are most concerned about EMI because of the highvolume of metals it refines annually, some facility processes being exempt from more currentand more stringent environmental pollution control regulations, and the perception ofuncontrolled releases. Residents are also concerned that the other facilities are likely contributingto a "toxic soup" of contamination that impacts their community, but that EMI is the greatestcontributor of air emissions in the area [2].

Area residents are concerned about the impact of the complex on their air quality and their health.They have reported a variety of symptoms, including: headaches, burning eyes, nausea, difficultybreathing, fatigue, muscle aches, tremors, sinus problems, bloody noses, a metallic taste in theirmouths, a bitter metallic taste in their throats, an ammonia smell, and sore throats. Residents are alsoconcerned about emissions of hexavalent chromium released through the chromium refining process,emissions from the electro-chromium process, and releases of chlorine and sulfuric acid used in therefining process [2].

Recent information provided by EMI suggests that only small amounts of hexavalent chromium,chlorine, and sulfuric acid are used in its processes. For example, EMI only uses small amountsof chlorine to disinfect treated sanitary wastewater discharging from its sewage treatment plant.Also, sulfuric acid is used only in amounts needed to adjust the pH of recycled process fluidsused for leaching raw materials in the electrolytic chromium department. Additionally, EMI'selectrolytic chromium process solutions consist primarily of trivalent chromium, becausehexavalent chromium in EMI's anolyte solution is reduced to trivalent chromium (less toxic) [3].

Because of the level of community concern regarding EMI, ATSDR staff toured the facility inMarch 2002. This facility is located in an area that is primarily rural and the facility lies several milesoutside the City of Marietta. The ferroalloy portion of the complex, which EMI bought in 1999,occupies approximately 350 acres of land. The ferroalloy operation, which produces iron alloys forthe steel, aluminum, and super-alloys industries, began in 1951. The ferroalloy operation includesseveral different refining processes. The facility is separated into a north and south side by a set ofrailroad tracks. To the north of the tracks are the electrolytic and briquetting operations that producehigh-quality chromium metal, aluminum hardener briquettes and other specialty products. To thesouth of the railroad tracks are three submerged arc furnaces that produce a full range offerromanganese and silicomanganese products for the steel industry. This area includes a"manganese oxygen refining" operation, which produces ferromanganese that contains limitedamounts of carbon and silicon [4]. EMI is the only producer of manganese ferroalloys in the UnitedStates, and is one of the largest manufacturers of these products in the world. In the year 2001, theToxic Release Inventory (TRI) reported that EMI released 371,400 pounds of manganese to ambient air. Although a limited number of emission control systems are in place for the ferromanganeseoperation (such as venturi scrubbers and baghouses), over half of the manganese emissions werereleased as "fugitive" or uncontrolled emissions [5].

In March 2003, ATSDR Region 5 staff requested that the ATSDR "Strike Team" (headquartered inAtlanta) assist in evaluating whether exposure to ambient air concentrations of metals reported in2001 and 2002 are of health concern or warrant additional evaluation. Specifically, the Strike Teamwas asked: "Do levels of contaminants in air pose a health risk to area residents?"


The Ohio Environmental Protection Agency (Ohio EPA) has collected air samples from a TotalSuspended Particulate (TSP) monitor since November 2000 [4]. The monitor is locatedapproximately 4.5 miles to the north/northeast of the facility on the roof of the WashingtonCounty Career Center, in a suburban area. Ohio EPA staff reported that the monitor was sited inits current location in response to a citizen complaint, and not specifically to address exposures toemissions to the Union Carbide complex [6]. An integrated air dispersion model has not beencompleted to determine if this location is the most highly impacted area of concern (i.e., the areawith the maximum ambient air concentrations from facility emissions).

The attached Ohio EPA data package (Appendix B) includes data from the monitoring locationfor 2001-2002. A TSP filter sample is collected every 6 days, and a composite of the samplescollected during a month is analyzed as a monthly average. The filters were analyzed for thefollowing metals: arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, and zinc.Historic air data from 1990 through early 1992 (located in a farmer's field outside Marietta) atanother location were also reviewed [7]. A comparison of air concentrations from 1990 to thepresent is limited by the fact that the 1990 monitor was in a different location than the currentmonitor (late 2000-present), and because it is not useful for assessing residential exposures (rurallocation). Interpreting recent data (since 2001) to infer exposures from the Union Carbidecomplex is complicated by the fact that the career center property contains a welding shop with astack, which likely emits detectable levels of metals.


In evaluating this site, ATSDR focused on the ability to assess health impacts based on the currentlyavailable air sampling data. ATSDR based its response on site conditions and information providedby Ohio EPA and the United States Environmental Protection Agency (USEPA). Two years and twomonths of recent data (Nov 2000 - Dec 2002) were reviewed for this evaluation. Approximately twoyears of historical data were also reviewed, but were not used to reach conclusions about current airconditions for the reasons mentioned in the previous section. In addition, volatile organic compound(VOC) data (1997, 2001-2002) and particulate matter data (1996-2000) of particles less than 10microns (PM10) were also monitored. PM10 and VOC levels detected at the locations and duringthe years sampled were not detected at levels of health concern. The Union Carbide complexfacilities emit other chemicals besides metals (e.g., ammonia, hydrochloric acid, chlorobenzene, etc.)in large quantities. For example, in 2001, EMI reportedly released 1,696,600 lbs of ammonia, AMPOhio released 1,200,100 lbs of hydrochloric acid, and Solvay Advanced Polymers released 106,000lbs of chlorobenzene [5]. However, there are very limited or no data for these other compoundsavailable for review at this time. Therefore, the focus of this document is the evaluation of ambientair concentrations of metals only.

To determine whether the level of contaminants could pose a health threat, ATSDR screens theconcentrations of contaminants against health based comparison values (CVs), and researchesscientific literature which may document health effects caused by exposure to contaminants. In thisevaluation, the ambient air metals data was compared to ATSDR chronic environmental mediaevaluation guides (EMEGs) and cancer risk evaluation guides (CREGs), and USEPA ReferenceConcentrations (RfCs) and inhalation unit risk factors. EMEGs are calculated from ATSDR minimalrisk levels (MRLs) for chronic or intermediate exposures (those occurring longer than 365 days orfrom between 14-365 days). CREGs are estimated contaminant concentrations expected to cause nomore than one excess cancer in a million persons exposed over a lifetime, and are calculated fromEPA's cancer slope factors (SFs) using default values for exposure rates. Both MRLs and RfCs areestimates of daily human exposure to a hazardous substance that is likely to be without appreciablerisk over a specified duration of exposure (based on scientific evidence).

Levels of arsenic, cadmium, chromium, and manganese exceeded the ATSDR and USEPA CVsduring both the 1990-1992 and 2001-2002 sampling periods. CVs are not available for lead or zincin ambient air. However, there were no exceedances of the USEPA National Ambient Air QualityStandard for lead of an average of 1.5 µg/m3 per quarter [9]. It should be noted that chromiumcomposition in the community's air is unknown (was not speciated, or broken down and measuredin its different forms, during lab analysis), and as a protective measure, ATSDR compared levels in Marietta to USEPA and ATSDR hexavalent chromium CVs.

Table 1. Metals above CVs: arsenic, cadmium, chromium, and manganese

Review of average concentrations and CVs, 2001-2002
Metal Average concentration 2001-2002 (µg/m3) Comparison Value (µg/m3) Agency Guideline
Arsenic 0.0016 0.00020 (Ca) ATSDR CREG
    0.00020 (Ca) USEPA
Cadmium 0.00070 0.00060 (Ca) ATSDR CREG
    0.00060 (Ca) USEPA
Chromium 0.00090 1.0 (N), 0.00008 (Ca) ATSDR MRL/CREG
    0.1 (N), 0.00008 (Ca) USEPA
Manganese 0.23 0.040 (N) ATSDR MRL
    0.051 (N) USEPA RfC

µg/m3= micrograms of metal per cubic meter of air

NOTE: ATSDR and USEPA health based comparison values are based on hypothetical risk analysis. Cancer riskcomparison value denotes an estimated 10-6 cancer risk (one excess cancer case per million exposed individuals).

(Ca) notates cancer endpoints, and (N) notates non-cancer endpoints.

There are naturally occurring levels of metals in outdoor air (called "background levels"). Generally,arsenic levels in outdoor air are between 0.001-0.003 µg/m3 in rural areas and 0.02-0.1 µg/m3 inurban areas. Concentrations of cadmium in ambient air are very low, generally less than 0.005 µg/m3;however, concentrations up to 0.5 µg/m3 have been detected in air near cadmium-emitting facilities.Chromium levels range from less than 0.01µg/m3 in rural areas to 0.01-0.03 µg/m3 in urban areas.Average manganese concentrations are approximately 0.005 µg/m3 in rural areas, and 0.033 µg/m3in urban areas in the United States. Although these numbers represent "typical" backgroundconcentration across the United States, it should be noted that levels of metals are often higher inindustrial areas [10-13].

The CVs used to evaluate these data address common human health inhalation exposurepathways. They do not consider all potential human health exposure pathways nor do theyaddress ecological concerns. The comparison of preliminary investigation data against risk-basedmedia concentrations provides for an initial evaluation for a set of environmental data. Thevalues are not regulatory, but are derived using equations from USEPA and ATSDR guidanceand commonly used defaults.

Arsenic and manganese consistently exceeded CVs between 2001 and 2002. Chromium exceededthese criteria several times, up to levels over 30 times the screening levels. Cadmium exceeded thislevel frequently during three months of the 26-month period. To better evaluate ambient contaminant concentrations in the future, additional metals should be included in future sampling.


It is difficult to infer the magnitude of the exposures or the potential health impacts from facilityemissions on the surrounding community from available monitoring. Current data demonstrate thatambient concentrations of arsenic, cadmium, chromium, and manganese have often exceededATSDR and USEPA health-based comparison values, used for evaluating chronic exposures.However, it should be noted that CVs are intended to be conservative, and are often orders ofmagnitude lower than levels where health effects have been observed. Therefore, when screeningvalues have been exceeded, it is often necessary to review scientific studies to further evaluatemeasured concentrations of contaminants in air. Levels of arsenic, cadmium, and chromium did notexceed levels of exposure that have been documented in scientific studies to cause adverse healtheffects in animals or humans [10-12].

Much of the scientific information that is used to evaluate the potential health effects of exposureto environmental contaminants is derived from animal research and studies of humanoccupational exposure. This is because information about the health impacts of community levelexposure to environmental contaminants is generally lacking. For manganese, the specificcriteria that both EPA and ATSDR use to evaluate inhalation exposure are based on occupationalstudies of workers exposed to relatively high concentrations of manganese, and who experiencesevere neurological effects [13]. However, community exposures tend to differ significantly fromoccupational studies in their frequency, duration, concentration, and exposure to sensitiveindividuals. Recent studies of community exposure to manganese in air suggest that there may behealth effects at relatively low levels [14-17].

It is possible that residents living closer to the facilities emitting these metals to air may have beenexposed to air concentrations higher than those seen in the available air monitoring data. Therefore,a more thorough characterization of ambient air in the areas most greatly impacted by facilityemissions is warranted. This may be accomplished by continued long-term sampling (1 year ormore) in locations identified as areas most greatly impacted by the Union Carbide complexemissions.


ATSDR recognizes that in communities faced with contamination of their air, water, soil, or food,the unique vulnerabilities of infants and children demand special emphasis. ATSDR is committedto evaluating the health impact of environmental contamination on children, and uses healthguidelines in its investigations that are protective of children. Further characterization of ambientlevels of metals is needed to evaluate the impact of facility emissions on children's health in this community.


No physical hazards were identified in this evaluation.


The ATSDR Strike Team was tasked with answering the question, "Do levels of contaminants in air pose a health risk to area residents?"

  • Available data suggest that metals in air, particularly arsenic and manganese (and to a lesserdegree, chromium and cadmium) could potentially pose a threat to residents close to thefacilities of concern because they exceeded health-based screenings values. However, at thistime, exposure cannot be adequately assessed because the locations for the air sampling datamay not reflect the most highly exposed populations, the current sampling location may alsocontribute to airborne metals, and the data analysis has included a limited number of metals.As a result, the magnitude of exposures and the threat to public health is uncertain (anindeterminate hazard).
  • Levels of particulates and volatile organic compounds are not present at concentrations of health concern at the current monitoring locations. However, no data are available to assess levels of these contaminants in areas closer to the industrial complex.
  • Some contaminants that are likely to be present, given facility processes, have not been sampled for (such as hydrochloric acid).


To better define the health threats, specific recommendations for collecting additional air sampling data are provided below.

  1. ATSDR or USEPA should model emissions from EMI, Eveready, Solvay, Chevron, andAMP Ohio to determine what contaminants could be present in ambient air, and the locationswhere they are likely to most significantly impact human health. This information will aidin determining the most appropriate locations for additional air sampling.

  2. After modeling is completed, ATSDR, Ohio EPA, and USEPA should determine whatadditional ambient air data is necessary to adequately investigate the impact of facilityemissions on the health of residents.

  3. When contaminants of concern have been identified, additional, long-term sampling should be performed (for 1 year or more).

  4. ATSDR should evaluate the data collected from additional air monitoring and air modeling (e.g., wind roses) to better assess air pollutant exposure levels and the potential for health consequences in area residents.


Michelle A. Colledge
Environmental Health Scientist
Office of Regional Operations
Region 5

Jennifer A. Freed
Environmental Health Scientist
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation

Reviewed by
Gregory M. Zarus
Strike Team Leader/Atmospheric Scientist
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation

John Abraham
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultation

Tina Forrester
Deputy Director
Office of Regional Operations

Mark Johnson
Senior Environmental Health Scientist
Office of Regional Operations
Region 5


  1. Agency for Toxic Substances and Disease Registry. Letter from petitioner to Agency for Toxic Substances and Disease Registry. May 22, 2000.

  2. Agency for Toxic Substances and Disease Registry. Notes from meeting with concerned community. Marietta, Ohio; March 24, 2002.

  3. Rik Melvin, Environmental Manager, EMI; written comments submitted to ATSDR December 15, 2003.

  4. EMI. Profile of Facility in Marietta, Ohio. November, 2000.

  5. United Stated Environmental Protection Agency. Toxic Release Inventory Database., accessed May 2003.

  6. Ohio Environmental Protection Agency. Raw data package for metals in air: 1990, 1991, 2001, 2002. Columbus, Ohio. Received March 26, 2003.

  7. Paul Koval, Supervisor, Air Toxics Unit, Ohio Environmental Protection Agency; communicated during March 26, 2003 conference call with OEPA, USEPA- Region 5, Ohio Department of Health, and ATSDR.

  8. Paul Koval, Supervisor, Air Toxics Unit, Ohio Environmental Protection Agency; personal communication with Mark Johnson, ATSDR. March 2003.

  9. Ohio Environmental Protection Agency. Air standard for lead. Ohio Administrative Code, Chapter 3745-71. Division of Air Pollution Control. Accessed May 9, 2003.

  10. Agency for Toxic Substances and Disease Registry. 2000. Arsenic, Toxicological Profile. Department of Health and Human Services.

  11. Agency for Toxic Substances and Disease Registry. 2000. Cadmium, Toxicological Profile. Department of Health and Human Services.

  12. Agency for Toxic Substances and Disease Registry. 2000. Chromium, Toxicological Profile. Department of Health and Human Services.

  13. Agency for Toxic Substances and Disease Registry. 2000. Manganese, Toxicological Profile. Department of Health and Human Services.

  14. Mergler D., Bladwin M., and Belanger S., et al. 1999. Manganese neurotoxicity, acontinuum of dysfunction: Results from a community-based study. Neurotoxicology 20 (2-3): 327-342.

  15. Baldwin M., Mergler D., and Larribe F., et al. 1999. Bioindicator and exposure data for a population based study of manganese. Neurotoxicology 20 (2-3): 343-354.

  16. Beuter A., Edwards R., and DeGeoffrey A., et al. 1999. Quantification of neuromotorfunction for detection of the effects of manganese. Neurotoxicology 20 (2-3): 355-366.

  17. Hudnell K. 1999. Effects from environmental Mn exposure: A review of the evidence fromnon-occupational exposure studies. Neurotoxicology 20 (2-3): 379-398.


Intro Map
Figure 1. Intro Map


Data Summary of Detected Ambient Metal Concentrations: 1990-91, 2001-02 (µg/m3)
Metal Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Health-Based Guideline
Arsenic No data collected 0.0015 0.00086 0.00066 0.0020 0.0016 ATSDR: 0.00020 µg/m3 (Ca)
USEPA: 0.0043 µg/m3 (Ca)
Beryllium 0.00006 0.00010 0.00010 0.00017 0.00003 ATSDR: 0.00040 µg/m3 (Ca)
USEPA: 0.020 µg/m3 (N)
Cadmium 0.00074 0.00051 0.00038 0.00060 0.00031 ATSDR: 0.0006 µg/m3 (Ca)
USEPA: 0.0018 µg/m3 (Ca)
Chromium 0.0051 0.0034 BDL BDL BDL ATSDR: 0.00008 µg/m3 (Ca)
ATSDR: 1 µg/m3 (N)
USEPA: 0.012 µg/m3 (Ca)
USEPA: 0.1 µg/m3 (N)
Lead BDL BDL BDL BDL BDL USEPA: 1.5 µg/m3 (N)
Nickel BDL BDL BDL BDL BDL ATSDR: 0.2 µg/m3 (N)
Zinc 0.044 0.037 0.031 0.036 0.029 No screening level
Arsenic 0.0012 0.0012 0.0014 0.0020 0.0058 0.0012 0.0076 0.010 0.0081 0.0037 0.0017 0.0052 See above
Cadmium 0.00029 0.00045 0.0010 0.00097 0.0013 0.00038 0.0057 0.0023 0.0010 0.0082 0.00067 0.0013 See above
Chromium BDL BDL BDL 0.0049 0.0061 0.0047 BDL 0.0062 0.0093 0.013 0.0072 BDL See above
Manganese NA NA NA NA 0.82 0.17 0.17 0.55 0.92 1100.0 0.37 0.43 ATSDR: 0.04 µg/m3 (N)
USEPA: 0.051 µg/m3 (N)
Zinc 0.027 0.036 0.029 0.086 0.054 0.048 0.064 0.22 0.16 0.33 0.20 0.19 No screening level
Arsenic 0.0014 0.00084 0.0011 0.0016 0.0012 0.0025 0.0018 0.0019 0.0013 0.0018 0.0024 0.0019 See above
Beryllium 0.00014 BDL BDL BDL 0.00006 0.00005 BDL BDL 0.00004 BDL BDL BDL See above
Cadmium 0.00055 0.00039 0.00023 0.00038 0.0026 0.00063 0.00026 0.00037 0.00028 0.00087 0.00071 0.0048 See above
Chromium 0.0048 BDL BDL BDL BDL BDL BDL BDL BDL BDL 0.0057 BDL See above
Lead 0.056 0.0066 BDL 0.0050 0.0050 0.0099 0.0082 BDL 0.0096 0.0090 0.011 0.011 See above
Manganese 0.096 0.13 0.16 0.19 0.12 0.33 0.10 0.094 0.027 0.73 1.4 0.42 See above
Zinc 0.11 0.025 0.022 0.026 0.033 0.044 0.024 0.043 0.033 0.054 0.062 0.040 No standard
Arsenic 0.0008 0.0022 0.00077 0.00027 0.0010 0.0018 0.0014 0.0062 0.00070 0.00070 0.00090 0.0010 See above
Cadmium 0.00077 0.00031 0.00016 0.00003 0.00024 0.0011 0.00064 0.00018 0.00020 0.00030 0.0003 0.0010 See above
Lead 0.0098 BDL BDL 0.00040 BDL BDL 0.0086 BDL 0.0010 0.0050 0.0090 BDL See above
Manganese 1.2 0.10 0.10 0.0070 0.020 0.089 0.11 0.083 0.010 0.010 0.070 0.010 See above
Zinc 0.068 0.033 0.031 0.0025 0.026 0.033 0.027 0.016 0.020 0.020 0.020 0.020 No standard

µg/m3= micrograms of metal per cubic meter of air

BDL: the metal was present at a concentration below the detection limit of the sampling analysis method.

Highlighted, bolded cells are concentrations which exceeded the ATSDR and USEPA health-based screening levels

NOTE: ATSDR and USEPA health based screening levels are based on hypothetical risk analysis.

(Ca) notates cancer endpoints, and (N) notates non-cancer endpoints.

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