Defining Hazardous Substances
There are many definitions and descriptive names used for hazardous materials — each depending on the context and purpose of the regulation or standard being applied.
Four labeled containers holding hazardous materials
If an employee were exposed to the chemicals in these containers, could they experience adverse health effects?
Because hazardous materials can pose different types of risks — to people, property, or the environment — federal, state, and local agencies define and regulate them according to their specific objectives. This often leads to variations in how “hazardous substances” are described and managed across agencies.
Agency-Dependent Definitions
Different government agencies define the term “hazardous substance” based on their specific areas of responsibility and regulatory focus. The Environmental Protection Agency (EPA) defines a hazardous substance as any chemical that, if released into the environment above a certain threshold, must be reported. Depending on the severity of the threat to the environment, federal involvement may be required to manage or mitigate the release. This definition and the list of regulated substances can be found in Title 40, Code of Federal Regulations (CFR), Part 302, Table 302.4.
The Occupational Safety and Health Administration (OSHA), on the other hand, defines a hazardous substance under 29 CFR 1910.120 as any substance which, through exposure, may result in adverse effects on the health or safety of employees. While the EPA’s focus is primarily on protecting the environment and the public from chemical releases, OSHA’s concern lies in safeguarding workers who may be exposed to these substances in the workplace.