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Research Programs: Human Health Risk
Mechanistic Information
Human Health Risk
The assessment of health risks posed by exposure to pollutants has traditionally been performed differently depending upon whether or not cancer is the outcome induced. Scientists previously believed all cancer was caused by toxic substances altering a person's DNA and that substances which did not cause cancer induced their effects through a different mechanism. An implication of these beliefs was that different assumptions were made about the relationship between the dose and effects of carcinogens than for pollutants which caused effects other than cancer.
Scientific advances of the past several years suggest that these assumptions are not necessarily valid. It is now known that some carcinogens induce their effects in ways other than through direct damage to a person's DNA. Additionally, some toxic substances can cause effects that are both cancer and non-cancer. Consequently, it is important for scientists to understand how a substance causes an effect at the most basic chemical and biological levels regardless of whether the effect is cancer or a different type of illness. Advancing this type of knowledge is a major focus of EPA's human health research.
Recognizing the need to develop a less fragmented approach to assessing risks and dealing with uncertainty, EPA scientists are working to derive a consistent, flexible set of principles and guidelines for using and drawing inferences from scientific information when they conduct risk assessments.
