The committee was asked to conduct a two-part study to assess and advance current approaches to toxicity testing and assessment undertaken to meet regulatory data needs. For the first part of the study, the committee was asked to review relevant aspects of several reports by EPA and others on the topic of toxicity testing and assessment. For the second part, the committee was asked to develop a long-range vision and strategic plan to advance the practices of toxicity testing and human health risk assessment of environmental contaminants. The present report fulfills the first part of the two-part study. The second report is expected to be completed by fall 2006. The committee was asked to focus on human toxicology and was not charged with reviewing toxicity testing and strategies designed to evaluate ecologic effects of environmental agents.
The committee heard presentations from representatives of several EPA offices, other federal agencies, and a number of organizations at public sessions, and it considered numerous documents and resources. The committee structured its review by first considering current toxicity-testing protocols. Recognizing that human data can be the most relevant for human health risk assessment, the committee considered the various types of human data available and the impediments that often prevent the use of epidemiologic data in regulatory risk assessment. Testing strategies used to rank, screen, or characterize substances were reviewed next. Various guidance documents that discuss the use of toxicity data for human health risk assessment were then considered. Finally, the committee reviewed some near-term improvements in toxicity-testing approaches proposed by others and some emerging technologies that may advance the field of toxicity testing.
Most of the documents reviewed by this committee describe initiatives or proposals that are still under development. Some have few details, and some were available to the committee only as drafts. Therefore, the committee focused on major themes rather than details, and it reviewed the documents primarily to compare various overall testing strategies and to evaluate the potential for the strategies to improve testing of environmental agents. The committee primarily examined toxicity-testing strategies rather than protocols for individual assays. Regarding documents that included an array of issues, the committee focused on the sections that dealt directly with toxicity testing and strategies and did not review sections that discussed risk-assessment approaches and policy issues, which were considered outside the scope of the committee’s task.