OU-1 & OU-2 Summary
Report Summary of LATAG”s commentary on EPA’s proposed plans for remediation of Operable Units 1 & 2. (OU-1 & OU-2)
Submitted on January 4, 2010
The Libby Area Technical Advisory Group (LATAG) operates with a Technical Assistance Grant from the EPA. The Group’s chief role is to help the community participate in decision making at the Libby Asbestos Superfund Site. Congress made public involvement in decision making an important part of the Superfund process, insuring that those whose lives are affected by hazardous material contamination should have a say in actions to clean it up.
LATAG provides the following summary of its comments on EPA’s proposed plans for clean-up of Operable Units 1 (former export plant) and 2 (former screening plant). The complete commentary document is available on request and will be available on the LATAG Website at:
Questions and comments are welcome and can be addressed at a regular LATAG meeting.
The next meeting will be 7 pm, January 12th, 2010 atFlathead Valley Community College.
The Libby Area Technical Advisory Group requested Terry Spear, PhD, the group’s technical advisor, to provide commentary on EPA’s proposed plans for remediation of Operable Units 1 and 2. The LATAG Board has been working with Dr. Spear under contract this past year, bringing his expertise to assist the group in review of clean-up activities and make recommendations.
Dr. Spear is a professor of industrial hygiene at the
University of Montana / Montana Tech., Butte, MT.
The LATAG Board has participated in the development of this document, and has reviewed and approved this final document generated by Dr. Spear for submission to the EPA in response to the request for commentary on proposed remedial plans for OU 1 and 2.
- The health risks associated with the inhalation of LA are uncertain. These uncertainties are outlined in my report, but they can be summarized by saying that the risks of developing cancer or non-cancerous health effects are uncertain, particularly at low exposure levels and when that exposure occurs in children or other susceptible people.
- The risk of non-cancer effects such as plural disease are not even addressed in current risk models. In Libby, plural disease maybe be more significant than the cancerous effects.
- It is my opinion that the uncertainties outlined above must be reduced, and that the cancer and non-cancer health effects, including health effects in children and other susceptible populations, at low dose exposure must be better understood before any record of decision is finalized in Libby.
- This better understanding of health effects must come from toxicological studies of LA, and epidemiological studies which will improve our understanding of the health effects of LA resulting from low dose exposure to susceptible populations.
- The methods used to quantify the levels of LA in air, soil, and dust, must be improved.
- Studies have implicated short, thin fibers (<5 um length and 0.25 um width) in non-cancer pulmonary effects. Given the significance of non-cancer adverse health effects in Libby, meaning that there is a high rate of plural disease, and given the fact that at least 50% of airborne fibers are short fibers (<5 um), analysis of air samples should be by TEM and short fibers must be taken into consideration when performing risk assessments.
- There has been limited activity-based sampling at OU1 and OU2, and this limited sampling makes the proposed Records of Decision highly uncertain. Extensive activity-based sampling, using TEM analysis to characterize the entire spectrum of exposures generated (size and type of amphibole), should be performed throughout the Libby Asbestos Site and within all Operable Units to determine potential cumulative exposure of residents to Libby amphibole.
- TEM analysis should be used to quantify LA concentrations in soil. This would allow the quantification of low levels of asbestos fibers in soil, including short, thin fibers. Given the relatively high levels (30%) of short fibers in Libby soil, use of the PLM method for final clearance is not appropriate. Given the limitations of the analytical methods used for identifying and quantifying LA in soils at OU1 and OU2, it is impossible to say that the pathways of exposure have been eliminated.
- The impacts of disturbing contaminated soil and dust on potential exposures at OU 1 & 2, and throughout Libby, must be better understood. This understanding would be improved by the use of better analytical methods and activity based sampling.
- In conclusion, it is clear that we still do not have enough information to estimate cancer and non-cancer risks from community exposures to LA associated with OU1 and OU2. Because of the complex multiple pathways of exposure to LA in the Libby area, uncertainties in exposure and risk of adverse health effects associated with OU1 and OU2 could result in an underestimate of cumulative cancer and non-cancer risks