This week's Topic In Depth focuses on the controversial subject of the effects of synthetic chemicals on hormonal systems and their potential impact on many aspects of human health. The first site (1) is a Why Files introduction to the endocrine system, the problem of endocrine disrupters, and what is being done to evaluate chemicals for endocrine disruption potential. Next is a Web site(2)...

The Exposure Factors Handbook provides summaries of available statistical data on several factors used in assessing human exposure to toxic chemicals.

The Environmental Protection Agency (EPA) has released a series of Parametric Probability Distributions to be used in conjunction with the previously released Exposure Factors Handbook. Whereas the Exposure Factors Handbook provides summaries of available statistical data on several factors used in assessing human exposure to toxic chemicals, the Parametric Probability Distributions document...

The US Department of Health and Human Services has recently made available its Report on Carcinogens (RoC), as prepared by the National Toxicology Program located at the National Institute of Environmental Health Sciences (NIEHS). Users may view the entire report on this Web site provided by Environmental Health Perspectives, a peer-reviewed journal published by NIEHS. The RoC is an authoritative...

The Agency for Toxic Substances and Disease Registry (ATSDR) is continually assembling toxicological profiles for hazardous substances. This site contains 256 online profiles listed alphabetically by chemical name. Each profile begins with a non-technical public health statement discussing the chemical, its environmental and health effects, and risk of human exposure. A more technical version of...