Rick Cooper/CASO/CAIBLM/DOl
To Arnold Den/R9/USEPAJUS@EPA, Jere Johnson
cc Karl Ford/NOC/BLM/DOl@BLM
04/11/2008 01:42 PM
bcc Janet BedrosianfCASO/CNBLM/DOl
Subject Uncertainty in model
Jere and Arnold,
Just reading through the executive summary. The last paragraph places some doubt as to the adequacyof the model used. The risks could be lower or 0. I am aware that EPA has been consistent in mentioning this and it was in the previous draft.
Uncertainty related to the toxicity parameters of the risk assessment includes the application of the IRIS and OEHHA asbestos toxicity models, which were developed from epidemiological studies of occupational exposures, to infrequent and episodic recreational exposures. This uncertainty could mean that the actual risks could be much lower than those estimated in the CCMA assessment and perhaps zero. Another uncertainty, adjustments for early-lifetime childhood exposures, could mean that the actual risks are higher than those estimated in the report.
I am sure BLM will be asked “why make an emergency decision on a model that may not accurately portray the risks to the public?” The basis for the decision is the model’s depiction that most of the activities exceed the acceptable risk range of 1 in 10,000.
Any thoughts on a reponse
Rick Cooper
Field Manager
Hollister Field Office
20 Hamilton Court
Hollister, CA 95023
phone: (831) 630-5010
I guess the EPA's reponse was something like: Oh, no big deal, we'll just take out those words to make your job easier, or something to that effect. What the hell, you're going to cloes it any way.
Here is the same paragraph from the EPA's final report:
Uncertainty related to the toxicity parameters of the risk characterization includes the application of the IRIS and OEHHA asbestos toxicity values, which were developed from epidemiological studies of occupational exposures, to infrequent and episodic recreational exposures. This uncertainty could mean that the actual risks could be much lower than those estimated in the CCMA assessment.