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### OPPT Proposed Draft Charge to External Peer Reviewers for the review of the TSCA Workplan Chemical Risk Assessment of DCM

December, 2012

Th is assessment focused on the use of DCM in paint stripping. T here are human health concerns

for both cancer and no n

- cancer effects with DCM use

- applicatio n

. This assessment of DCM paint stripping uses focus ed only on inhalation exposure to workers, consumers , and bystanders

.

General question on the risk assessment

Issue 1. General Question on the Risk Assessment of DCM

. The document describes the scope for the DCM human health risk assessment (Chapter 1); provides information on chemistry, environmental fate and transport, production, and uses (Chapter 2); and characterizes exposure, hazard, and risk (Chapter 3). Supporting information is provided in appendices. The risk assessment is intended to provide a clear and transparent summary of EPA’s analysis.

Question 1

- 1: Please comment on whether the assessment provide s a clear and logical summary of EPA’s analy sis

. P lease provide specific suggestions for improving the

document.

Question 1

- 2: Please comment on whether appropriate background information is provided and accurately characterized

. Please provide any other significant literature, reports, or dat a that would be useful to complete this assessment.

Questions on the exposure assessment of DCM

Issue 2

. EPA found l imited published data for DCM air concentrations in workplace settings during use of DCM

- based paint strippers. These data were used for estimating occupational inhalation exposures.

Question 2

- 1 : What other sources of data are available to estimate inhalation occupational

exposures. P lease provide specific citations.

Question 2

- 2 : Please specify other data that could be used to est imate occupational d ermal exposures during use of DCM

- based paint strippers

. Please specify sources of these data

.

Issue 3. Inhalation exposures for consumer uses of DCM in paint stripping were estimated using the EPA’s Multi

- Chamber Concentrations and Exposure Model (MCCEM). EPA conducted a sensitivity analysis of model parameters to identify critical parameters essential to the modeling approach used to estimate inhalation exposures. This analysis guided the selection of exposure scenarios and provi ded the most sensitive input parameters for generating upper end concentrations.Page 2 of 2 Question 3

- 1 : Please comment on the strengths and weaknesses of model evaluati o n of different exposure scenarios

.

Question 3

- 2 : Please comment on the choice of assumption s/ input parameters for generating upper end concentrations and provide specific suggestions for improving this approach. Please specify other sources of these data.

Questions for the assessment of human health and risks of DCM

Issue 4. EPA used inform ation from the Cal EPA reference exposure level to develop an

a cute exposure hazard for inhalation uses of DCM in paint stripping . This was based upon

deficits in c ognitive and sensory performance in humans following short term acute exposures to DCM. In addition

, for comparison

, EPA also included information on endpoints from acute exposure guideline levels (AEGLs) to illustrate “ context exposure

response levels for endpoints across a range of adversity ”

.

Question 4

- 1: Please comment on the assumption s and the strengths and weakness of this approach to provide “context exposure

- response levels for endpoints across a range of adversity”

. P rovide feedback on other critical endpoints that could be considered further

enhance the characterization of the ha zard of acute inhalation exposures

. P lease provide data or documentation and rationale for including other studies and endpoints to be considered.

Issue 5. The Chronic non

- cancer risks were assessed using liver damage in rats as the Point of Departure (POD)

.

Question 5

- 1: What other critical endpoints could be considered to further enhance the

characterization of the hazard of chronic inhalation exposures for DCM

- paint stripping applications ? P lease provide data or documentation and rationale for inc luding other studies and endpoints for consideration

.