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MDE classified the MAWP site as a public health hazard. This classification is applied by ATSDR to sites which pose a public health hazard as a result of long-term exposure to hazardous substances (ATSDR, 1992). MDE applies this classification to the MAWP site for the following reasons:

  1. Workers who breath dust from chromium-contaminated dust from on-site areas may experience a slightly elevated cancer risk;
  2. Young children (likely to exhibit pica behavior) who are in frequent contact with chromium-contaminated soil from off-site areas may possibly experience a small increased risk of developing liver and kidney disease following long-term exposure;
  3. Workers who breath and ingest arsenic-contaminated particulates from on-site soil may experience a small increase in cancer risk; and
  4. Children who very frequently play and ingest arsenic- contaminated soil near the off-site sewer outfall may be at small increased risk of developing cancer.

Initial remediation efforts taken at the site reduced the concentrations of on-site contaminants below an acutely hazardous level. The issues of concern about on-site workers (points 1 and 3 listed above) are no longer valid, except for remedial workers, who are expected to follow health and safety plans. Once remediation is complete, the site should no longer pose a public health concern.

Exposures of concern at the site are summarized as follows: current and past inhalation of fugitive dust and incidental ingestion of surface soil, and past ingestion of groundwater. On-site exposure to the soil pathways was reduced in 1990 by covering contaminated soils on site with clean gravel as an interim measure. Exposure to off-site contaminated soils is minimized by the heavy vegetation of the area, which limits the production of fugitive dust, and the site's relatively isolated location. After contamination was discovered in groundwater, wells used for drinking water were immediately replaced with service from the municipal water supply. Furthermore, the concentrations of the contaminants of concern have declined over time. Thus, past exposure to these media is the major focus of concern for human health at this site; however, contaminated soil continues to pose a slightly elevated health risk to on-site workers and nearby residents. Planning for the remedial work to reduce the exposures to on-site contaminated soils is entering the final phase of completion.

Specific health outcomes of concern are: lung cancer and respiratory disease from past and current inhalation of arsenic and chromium in fugitive dust and possible liver and kidney disease from chromium in off-site soil (for children only). It is important to note that the appearance of site-related liver and kidney disease is highly improbable since the opportunities for exposure are so restricted, and even if exposure should occur, the chromium in soil is likely to be in the trivalent form that does not produce such an adverse effect.


The MDE recommends that the cleanup strategy outlined in the Record of Decision be implemented as soon as possible and that further community health concerns be addressed as they develop. On-site levels of chromium and arsenic should be cleaned up to safe levels. Off-site contamination should be more completely characterized. Long-term monitoring of air and water at the site, as proposed in the remediation plan, should also be carried out. Air samples should be taken so that potential risk of cancer from arsenic and chromium through the inhalation route can be evaluated with real data rather than model estimates.

Long-term cancer surveillance of neighboring workers and residents is not recommended because it is unlikely to reveal any cases of cancer attributable to the site. This is because the potential excess cancer risk associated with the contamination levels at or near the site is relatively low as is the number of persons who could be exposed to these site-related contaminants. Furthermore, the opportunities for community exposure are limited by the characteristics of the site: a chain link fence surrounding the site, an isolated location, and heavy vegetation around the site. The maximum period of potential community exposure to hexavalent chromium in groundwater was limited to 4 years, from 1974 when the MAWP began operations until 1978 when the spill was discovered and residents were connected to a municipal water supply; however, because no samples were taken prior to 1978, it is not known whether or not exposure to hexavalent chromium before 1978 actually occurred. In contrast, MAWP employees, who have had higher exposures than the surrounding community, should be monitored for cancer.

Finally, as a precautionary measure, parents should be advised to prevent their children from playing daily in the vicinity of the sewer outfall, located northwest of the site.

Health Activities Recommendation Panel (HARP) Recommendations

The data and information developed in the Mid-Atlantic Wood Preservers Public Health Assessment have been evaluated for appropriate follow-up health actions. The ATSDR Health Activities Recommendation Panel (HARP) determined:

  1. To protect MAWP workers from the potential toxic effects of exposure to chromated copper arsenate, MDE needs to notify the appropriate Maryland agency about site conditions so that MAWP managers and workers are informed of the regulations that should be followed to protect worker health.
  2. The community needs to be notified that the Public Health Assessment for this site is available for public comment. The notification should mention that, to minimize possible exposure to arsenic in soil, small children should not be allowed to play on a regular basis in the immediate vicinity of the sewer outfall. The outfall is located northwest of the site.
  3. HARP agrees with MDE's conclusion that additional health studies of nearby residents should not be done because they are unlikely to reveal cancers or birth defects that could be attributed to the site. However, MAWP workers potentially receive much higher exposures to chromium and arsenic than neighboring residents. Therefore, MAWP workers should notify their physicians about their potential exposures and about the increased risk of developing cancer as a result of those exposures.

ATSDR will reevaluate this site for additional follow-up public health actions if new data become available that indicate a need to do so.

Public Health Actions

The public health action plan (PHAP) for the Mid-Atlantic Wood Preservers site contains a description of actions to be taken by ATSDR and/or other governmental agencies at and in the vicinity of the site subsequent to the completion of this public health assessment. The purpose of the PHAP is to ensure that this public health assessment not only identifies public health hazards, but provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. Included is a commitment on the part of MDE and ATSDR to follow up on this plan to ensure that it is implemented. Based on the recommendations made in this Public Health Assessment, the following public health actions have been or will be undertaken.

Actions Undertaken

To explore whether the MAWP was in compliance with regulations to protect workers from potentially harmful chemical exposures, MDE contacted the Maryland Occupational Safety and Health (MOSH) division of the Maryland Department of Licensing and Regulation. MOSH indicated that the MAWP premises were most recently inspected by MOSH staff as part of a routine, planned investigation on July 24, 1992. MOSH inspectors certified that the MAWP was in compliance with health and safety, and worker right-to-know regulations. Therefore, MDE is satisfied that workers were adequately protected from potentially toxic exposures to chromated copper arsenate. No further actions by MDE are necessary to fulfill the first HARP recommendation above because the facility is now closed.

To insure that samples were obtained from the highest zone of arsenic contamination, additional samples from shallow on-site soils and fill were taken by MDE's CERCLA's Response Division in April 1992 and by MAWP's contractor in June 1992. This sampling revealed that a wider area of shallow soils than previously thought had elevated arsenic levels. As a result, a greater proportion of the MAWP surface will be paved in accordance with the criteria established in the Record of Decision to reduce any potential human health risks from arsenic.

The public was notified of the availability of the public health assessment. Comments were received, and those comments, with a response to those comments, appears in the Attachment of this document.

Actions Planned

Because the facility is closed and plans for remediation of the site are sufficient to prevent human exposure, no further actions are warranted on this site.


Carolyn A. Nunley, M.P.H.
Environmental Toxicologist
Environmental Toxicology and Risk Assessment Division
Maryland Department of the Environment

Robin M. Wagner, M.S.
Environmental Toxicologist
Environmental Toxicology and Risk Assessment Division
Maryland Department of the Environment

Principal Reviewers:

Peter Ashley, M.P.H.
Environmental Toxicologist
Environmental Toxicology and Risk Assessment Division
Maryland Department of the Environment

Shirin De Silva, M.D., M.P.H.
Environmental Epidemiology Division
Maryland Department of the Environment

Data and Technical Reviewer:

George Herold
CERCLA Response Division
Hazardous and Solid Waste Management Administration
Maryland Department of the Environment


Regional Representative:

Charles Walters
Public Health Advisor
Field Operations Branch

Project Officer:

Gail Godfrey
State Programs Section
Remedial Programs Branch


The Mid-Atlantic Wood Preservers Site Public Health Assessment has been prepared by the California Department of Health Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was initiated.

Gail D. Godfrey
Technical Project Officer, SPS, RPB, DHAC

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment and concurs with its findings.

Robert C. Williams, P. E., DEE
Director, DHAC, ATSDR


Agency for Toxic Substances and Disease Registry (ATSDR), Public Health Service, U.S. Department of Health and Human Services, Public Health Assessment Guidance Manual, Atlanta, March 1992

Agency for Toxic Substances and Disease Registry (ATSDR), Public Health Service, U.S. Department of Health and Human Services, Toxicological Profile for Arsenic, Draft, October 1991a.

Agency for Toxic Substances and Disease Registry (ATSDR), Public Health Service, U.S. Department of Health and Human Services, Toxicological Profile for Chromium, Draft, October 1991b.

Anne Arundel County Office of Planning and Zoning (AACOPZ), "Anne Arundel County 1990 Census Data," Annapolis, MD, May 1991.

Bionetics Research Labs (BRL), "Evaluation of Carcinogenic, Teratogenic and Mutagenic Activities of Selected Pesticides and Industrial Chemicals. Vol. I. Carcinogenic Study Prepared for the National Cancer Institute," NCI-DCCP-CG-1973-1-1, 1968. (Cited in ATSDR, 1990).

Dames and Moore, "Draft Feasibility Study Report, Mid-Atlantic Wood Preservers Site, Harmans, Maryland," Bethesda, MD, July 20, 1990a.

Dames and Moore, "Remedial Investigation (RI) Report, Mid-Atlantic Wood Preservers Site, Harmans, Maryland," Bethesda, MD, January 15, 1990b.

Demerec, M., Bertani, G., Flint, J., "A Survey of Chemicals for Mutagenic Action on E.Coli, American Nature, 81, 1951, p. 119. (Cited in ATSDR, 1990).

Mancuso, T.F., "Consideration of chromium as an industrial carcinogen," In Hutchinson, T.C., ed. Proceedings of the International Conference on Heavy Metals in the Environment, Toronto: Toronto Institute for Environmental Studies, 1975, p. 358-363. (Cited in ATSDR, 1988).

Nordstrom, S., Beckman L., and Nordenson, I., "Occupational and Environmental Risks in and around a Smelter in Northern Sweden. I. Variations in Birthweight," Hereditas, 88, 1978a, p. 43-46. (Cited in ATSDR, 1989).

Nordstrom, S., Beckman L., and Nordenson, I., "Occupational and Environmental Risks in and around a Smelter in Northern Sweden. III. Frequencies of Spontaneous Abortions," Hereditas, 88, 1978b, p. 51-54. (Cited in ATSDR, 1989).

Nordstrom, S., Beckman L., and Nordenson, I., "Occupational and Environmental Risks in and around a Smelter in Northern Sweden. V. Spontaneous Abortions Among Female Employees and Decreased Birth Weight in Their Offspring," Hereditas, 90, 1978c, p. 291-296. (Cited in ATSDR, 1989).

Telecon between David Kindig and Rich Sappington, Anne Arundel County Water Department, of May 23, 1984 in: NUS Corporation (NUS), "A Hazard Ranking System for Mid-Atlantic Wood Preserves", Prepared under TDD No. F3-8212-50, EPA No. 70, Contract No. 68-01-6699 for the Hazardous Site Control Division, U.S. Environmental Protection Agency, June 6, 1984.

Tseng, W.P., Chu, H.M., How, S.W., Fong, J.M., Lin, C.S. and Yeh, S., "Prevalence of Skin Cancer in an Endemic Area of Arsenism in Taiwan," J. National Cancer Institute, 40, 1968, p. 453-463. (Cited in ATSDR, 1989).

U.S. Environmental Protection Agency (USEPA), Record of Decision Mid-Atlantic Wood Preservers Site, Harmans, Anne Arundel County, Maryland, December 31, 1990.

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