Study in Progress

Assessing Toxicologic Risks to Human Subjects Used in Controlled Exposure Studies of Environmental Pollutants

Statement of Task

An ad hoc committee will address scientific issues and provide guidance on the conduct of controlled human-exposure studies designed to inform policy decisions and set air-pollutant standards to protect public health. The committee will consider EPA's Office of Inspector General report titled Improvements to EPA Policies and Guidance Could Enhance Protection of Human Study Subjects, which recommends improvements to EPA's conduct of studies and outlines how the agency intends to address the recommendations. Relevant issues and questions for the committee to address include the following:

-- EPA has performed controlled human-exposure studies to help understand exposure to and potential health effects of common air pollutants, such as particulate matter. To what extent have such studies been valuable to inform and reduce uncertainties in setting pollutant standards? Is it warranted to continue to conduct controlled human-exposure studies as part of EPA's larger research agenda for air pollutants?

-- The committee will assess the potential health risks to test subjects who participated in recent studies of air pollutants at EPA's clinical research facility and comment on the degree of actual risk imposed by the exposures in those studies.

-- If the committee supports continued conduct of human exposure studies, it will provide further guidance in the following areas:
* Methods for estimating levels of risk in controlled human-exposure studies, drawing from relevant approaches used in Phase I clinical drug trials.
* A template to characterize reasonably foreseeable risks, in terms of the nature, frequency, and magnitude of possible risks, which could be used in obtaining informed consent from potential study participants. The literature on "challenge studies" should be considered in the design of the template, if applicable.