CHEMICAL PROFILES|Safety Assessment of Toxic Chemical Releases and Exposures

How safe a chemical is in the environment depends on:
(1) how toxic it is (how much of the chemical does it take to cause an adverse health effect); and
(2) how much of it people are exposed to (who, where, and in what amounts).

When information about toxicity and exposure is available for a specific chemical, it can then be combined to provide a scientific evaluation of potential health risks. This process, called risk assessment, becomes the basis for legal and social judgments about the safety or acceptability of chemical releases. Many key laws that Congress has passed over the last 25 years to protect the public from toxic chemical risks cannot be activated if the necessary information is not available; i.e., those laws cannot provide the protection they promise.

For chemicals that have been identified as potential health hazards, two types of information are required to conduct a safety assessment:

1) Risk assessment values (or media quality standards)

Risk assessment values and media quality standards are numbers that help define the level of health risk posed by a toxic chemical. Risk assessment values are summary measures of the toxic potency of a chemical. They are combined with information about the exposure to a chemical that someone receives to characterize health risks. Media quality standards set legal limits on the concentration of chemical contaminants in air, water or food. Scorecard considers chemicals with risk assessment values or media quality standards that have been developed by state or federal regulatory or scientific agencies as having the toxicity data required for safety assessment.

More on the availability of risk assessment values or standards.

2) Exposure data

Exposure data are used to estimate the dose of toxic chemicals people take in as a result of breathing polluted air, drinking contaminated water, etc. To determine whether a chemical has exposure data, Scorecard tracks whether chemicals are the subject of national or state monitoring programs or have been covered by national exposure estimation projects.

More on the availability of exposure data.

Scorecard's chemical profiles track whether information about a chemical's toxicity and information about exposures are publicly available. If these data are available, Scorecard indicates that its safety can be assessed. If not, Scorecard indicates what kind of data are missing (toxicity and/or exposure).