Output Explorer

John Cowden, Ph.D.
Janice Lee, Ph.D.
January 28, 2013
Page 2
Additionally, it would be helpful to give the public sufficient advance notice of upcoming
stakeholder meetings to provide all stakeholders with an opportunity to suggest panelists for the
workshops. Unfortunately, scientific experts with industry experience and perspectives were not
sufficiently represented at the stakeholder workshop. To the extent possible, the panels should be
balanced to represent as many scientific perspectives as possible. Going forward, if the IRIS
Program needs assistance in identifying experts with industry experience, ACC would be glad to
provide suggestions.
As was discussed at the workshop, it is clear that there is already a great deal of scientific
information, as well as consensus, regarding the effects of inorganic arsenic at high doses which are
not relevant to today's environmental exposures in the U.S. However, there did not appear to be
agreement regarding human health risks at low dose exposures. We were thus disappointed that the
draft Scope does not specifically focus on evaluating cancer and non-cancer health effects in the
exposure range relevant to U.S. citizens. As part of scoping and planning, EPA could conduct
surveys, review literature, and take public comment on what the appropriate range of exposures
should be to conduct a focused and targeted assessment.
In addition, we suggest that mode of action be considered as a central organizing principle of the
assessment. In this manner, data from laboratory experiments, epidemiological investigations, and
cutting-edge mechanistic research from all relevant studies and from all investigators, regardless of
affiliation or funding source, can be comprehensively reviewed, given appropriate weight, and
integrated in a manner that provides a robust, biologically plausible understanding of the potential
hazards and risks that environmentally relevant exposures could pose. The extent to which the data
do or do not support specific hypothesized modes of action can then be compared.
The draft Scope should also describe the approaches that will be used for developing the dose
response relationships for evaluating potential risks to humans at environmentally relevant levels of
exposure. ACC encourages EPA to evaluate and include alternative extrapolation models,
including scientifically plausible threshold models for the analysis of cancer data in addition to a
default linear model to account for the uncertainties associated with the dose response extrapolation.
Such an approach would be consistent with the EPA 2005 Guidelines for Carcinogen Risk
Assessment as well as the recommendations provided to EPA in the 2011 National Academies
Review of the EPA's Draft IRIS Assessment of Formaldehyde. Furthermore, to ensure appropriate
context for risk managers and policymakers and to promote a more complete characterization of
potential hazards and risks, the scoping document should contain plans for including in the
assessment 1) central tendency estimates of dose-response curves in addition to upper bound
estimates and 2) a plausibility check to compare the resulting reference values and cancer risk value
estimates with data on the actual health outcomes at environmentally relevant levels of exposures.
It would also be useful for the draft scope to describe the qualitative and quantitative approaches
that will be used to evaluate uncertainties associated with the risk values that will be derived.
In conclusion, we believe sharpening the focus of the scope of the hazard identification and dose-
response analyses to the most relevant range of exposures and on the key scientific issues such as
Source: https://www.industrydocuments.ucsf.edu/docs/ngcn0226

Answer the question using only the OCR text from a single document page. Return only the answer, with no explanation. Preserve the answer wording from the OCR text when possible.