The nature, extent, and focus of a risk assessment should be guided by the risk management goals. Risk assessment can be controversial, reflecting the important role that both science and judgment play in drawing conclusions about the likelihood of effects on human health and the environment. Often, the controversy arises from what we don't know and from what risk assessments can't tell us, because our knowledge of human vulnerability and of environmental impacts is incomplete, especially at the relatively low levels of chemical exposure commonly encountered in the general community. A good risk management decision is based on a careful analysis of the weight of scientific evidence that supports conclusions about a problem's potential risks to human health and the environment. Risk results from a combination of hazard and exposure.
Exposure means contact between the hazardous substance and a person, population, or ecosystem.
The more exposure, the greater the risk. When there is no current or potential exposure, there is no risk. Risk assessment is performed by considering intrinsic hazards, the extent of exposure to the hazards, and information about the relationship between exposures and responses. Unfortunately, we seldom have enough information to accurately determine hazards, exposures, or exposure-response relationships, so risk assessors must use a combination of scientific information and their best judgment to characterize risks. Appropriateness of the toxicity study methods.