WHAT IS SAFETY ASSESSMENT?
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.
HOW DOES SCORECARD DETERMINE WHETHER HAZARDOUS AIR POLLUTANTS CAN BE ASSESSED FOR SAFETY?
Information about a chemical's toxicity (known as risk assessment values) and information about exposures are both needed before a scientific risk assessment of a specific chemical can be performed.
These are the basic components of chemical safety assessment. Scorecard tracks whether these types of information are publicly available for the 188 toxic chemicals or compounds listed as Hazardous Air Pollutants (HAPs) under Section 112 of the Clean Air Act.
If a chemical has publicly available risk assessment values or media quality standards, Scorecard considers it has the toxicity data required for safety assessment. If a chemical has publicly available data that describes its concentration in specific media (i.e., air), Scorecard considers it has the exposure data required for safety assessment. If the relevant data for a chemical are not available, Scorecard indicates that its safety cannot be assessed.
Scorecard evaluates safety data availability for HAPs by assessing whether they possess inhalation risk assessment values (either cancer or noncancer) and ambient air exposure data. There are 5 HAPs which lack the toxicity data and 37 HAPs which lack the exposure data required to assess the safety of ambient air exposures.
To obtain information about the risk assessment values or exposure data available for a specific chemical, click on its name to obtain a chemical profile and review the Information Needed for Safety Assessment section.
IMPORTANT CAVEAT - IGNORANCE MAY BE UNDERSTATED
Scorecard makes generous assumptions when evaluating the availability of toxicity and exposure data that result in an understatement of the degree of ignorance about the safety of ambient air exposures to HAPs. In its assessment of data availability, Scorecard credits some risk assessment values and exposure data that federal agencies like EPA or state governments have not adopted for use in regulatory efforts to control HAPs.