FINDING: EPA's practice appears to be to allow departure from a default option in a specific case when it ascertains that there is a consensus among knowledgeable scientists that the available scientific evidence justifies departure from the default option. EPA, though, has not articulated criteria for allowing departures.
RECOMMENDATION: The agency should consider attempting to give greater formality to its criteria for a departure, to give greater guidance to the public and to lessen the possibility of ad hoc, undocumented departures from default options that would undercut the scientific credibility of the agency's risk assessments. At the same time, the agency should be aware of the undesirability of having its guidelines evolve into inflexible rules.
FINDING: EPA has relied on its Science Advisory Board and other expert bodies to determine when a consensus among knowledgeable scientists exists.
RECOMMENDATION: EPA should continue to use the Science Advisory Board and other expert bodies. In particular, the agency should continue to make the greatest possible use of peer review, workshops, and other devices to ensure broad peer and scientific participation to guarantee that its risk-assessment decisions will have access to the best science available through a process that allows full public discussion and peer participation by the scientific community,
FINDING: EPA has not stated all the default options in each step in the risk-assessment process, nor the steps used when there is no default. Chapters 7 and 10 elaborate on this matter and identify several possible "missing defaults."
RECOMMENDATION: EPA should explicitly identify each generic default option in the risk-assessment process.