Final answer:
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as the Superfund Act, addresses the problem of inactive hazardous waste sites.
Step-by-step explanation:
The Federal Act that addresses the problem of inactive hazardous waste sites is the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). CERCLA, also known as the Superfund Act, was passed by Congress in 1980 and provides the framework for the cleanup and management of hazardous waste sites in the United States. It established the Superfund program, which is responsible for identifying, investigating, and cleaning up contaminated sites.