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30 August 2004
File No. 10063-066
Massachusetts Department of Environmental Protection
One Winter Street
Boston, Massachusetts 02108
Attention: Mr. Jack Miano
Subject: Response to Comments on Phase II Asbestos Risk Characterization W.R.
Grace & Co-Conn.
62 Whittemore Avenue
Ladies and Gentlemen:
On behalf of W.R. Grace & Co.-Conn. (W.R. Grace) Haley & Aldrich is responding to your letter dated 13 July 2004 which provided comments on the Risk Characterization included in .the Phase II Comprehensive Site Assessment Report for Asbestos (Phase II CSA). The Phase II CSA was prepared by Haley & Aldrich and submitted to the Department on 8 January 2003. The Phase II CSA included a Method 3 Risk Characterization prepared by Cambridge Environmental, Inc. to assess the potential risks associated with the presence of asbestos fibers in soil and groundwater at the W.R. Grace property (the Site).
The risk characterization identified No Significant Risk to human health under current (nonexcavation) site conditions. For the foreseeable future use, which included evaluation of hypothetical construction, the risk characterization concludes that there is No Significant Risk to safety, public welfare, or environment. The risk characterization also concludes that there could be Significant Risk to the health of a construction worker during the assumed construction and there could be Significant Risk to the nearby resident if subsurface soils containing higher concentrations of asbestos fibers were placed at the surface of the Site in the future.
The following provides a brief summary of comments provided in your letter regarding the Risk Characterization-
I . The Department recommends the use of the 60 ug/m3 default level for PM10 dust as the initial site concentrations at the site boundaries during excavation activities rather than the site specific value derived by Cambridge Environmental. This default value should be used to evaluate exposures to onsite and offsite receptors during construction (Comments Nos. 1 and 2 in DEP letter).
2. Residential use was not evaluated as a potential future site use. Therefore, residential property use will need to be restricted through the use of an Activity & Use Limitation (AUL) (Comment No. 3).
3. The Department recommends the use of the Interim Superfund Method for the Determination of Releasable Asbestos in Soils and Bulk Materials (Berman & Kolk, 19995) to obtain data which can be used to model future asbestos concentrations in air (Comment No. 4).
4. The Department noted that they are not aware of information to support the concept presented by the Agency for Toxic Substances and Disease Registry (ATSDR) that background levels of asbestos in soil may possibly be attributable to vehicle brakes in urban areas. (Comment No. 5).
5. The Department presented some general guidelines for asbestos measurements including recommendations for the when to use of the EPA Region 1 Protocol and when to use the Interim Superfund Method and how to correlate data from the two different analyses (Comment No. 6).
We infer that the Department's continents are generally intended to address concerns that possible future exposures to asbestos fibers in the soil at the site (particularly under a hypothetical construction scenario) need to be re-evaluated using different analytical methods and revising a few assumptions in the models used in the risk characterization.
We believe that some additional information which was not available at the time Haley & Aldrich submitted the Phase II CSA may address the concerns presented in you letter. Haley & Aldrich is currently in the final stages of preparation of an Activity & Use Limitation (AUL) for the W.R. Grace Site. The AUL will be used to support a Class A-3 Response Action Outcome (RAO) for the Site. The draft AUL was not available to be presented in the Phase II CSA in January 2004. The following sections discuss the measures in the AUL which we believe to protective of public health, safety, welfare and the environment.
The AUL addresses the risks identified in the risk characterization (construction worker and future resident) as follows:
· Requiring the implementation of a soil management plan designed to control airborne particulates (dust and asbestos) during future excavations which might be completed at the Site. The plan will required the use of a combination of various soil management techniques, such as wetting and the use of barriers to cover the soil.
· Requiring construction workers to conduct work in accordance with a site and project specific health & safety plan for future excavations which might be completed at the Site.
· Controlling unauthorized access to the work area.
· Requiring that only clean backfill materials be placed at the surface of the site, should future excavation be conducted at the Site.
· Restricting the use of the site for future residential purposes.
· Complying with all other applicable local, state, and federal regulations governing the activities will also be required.
Additionally, due to the perceived imprecision in the Risk Characterization calculations and the sensitive nature of this site, the AUL also includes provisions to, control potential future exposures to asbestos fibers for nearby residents during potential future construction activities. The control measures required by the AUL include:
· Implementing an airborne dust and fiber management and monitoring plan during future excavations which might be completed at the Site to demonstrate that the controls are functioning as intended. The plan will include dust and fiber monitoring at the perimeter of the Site and establishes action levels which will trigger work stoppage and re-evaluation of the soil management control measures. .
These measures are intended to be further protective of public health, regardless of the conclusion in the risk characterization that there is no significant risk to human health to the nearby resident due to inhalation of asbestos fibers during a hypothetical construction scenario. Haley & Aldrich believes that these measures will be protective of public health, safety, welfare and the environment.
The approach used in the Phase 11 CSA risk characterization concluded that there was potential future risk under an uncontrolled, large-scale excavation scenario. An alternative method of analysis (such as the Interim Superfund Method) or revised modeling assumptions would either support the conclusion that there is potential future risk, or, it is possible that the alternative method of analysis would support the conclusion that there is No Significant Risk in the future. If it were concluded that there is no risk under future excavation scenarios, future construction would be allowed under the MCP, with no extraordinary risk management procedures. Therefore, we believe that the approach selected for the Phase II CSA, which concludes that there is potential ft=re risk and the implementation of the AUL outlining management procedures to control that risk, is the more appropriate approach for this property.
As mentioned above, the AUL and Class A-3 RAO for the Site are in the final stages of preparation. The risk characterization supporting the RAO will use the existing site data to address the concerns presented in your letter and the responses contained in this letter. A public comment draft of these document will be submitted to the Department, the PIP repositories, and interested parties for review and comment. Additionally, W.R. Grace and Haley & Aldrich will also host a public meeting to discuss the documents and address questions and concerns. We anticipate the public comment draft documents will be available for review by September 2004. A public meeting will be scheduled once the documents have been made available for review.
We hope that the information presented in this letter adequately addresses the concerns present in your letter. Please contact us if you have any questions or would like to discuss this matter further.
HALEY & ALDRICH, INC.
Melissa M McEwen
Senior Environmental Geologist
William W. Beck, Jr., LSP
Senior Vice President
c: Ms. Patricia Donahue; Department of Environmental Protecitons
Cambridge Main Library
North Cambridge Library
Mr. John Bolduc; City of Cambridge, Community Development Department
Mr. Kenneth Reaves; City of Cambridge, Office of the City Manager
Mr. Mike Nakagawa; Alewife Neighbors, Inc.
Representative Alice Wolf, Massachusetts State House
Representative James J. Marzilli; Massachusetts State House
Representative Anne M. Paulsen, Massachusetts State House
Contact the Alewife Study Group, North Cambridge Massachusetts, by email at email@example.com