Final answer:
The Toxic Substances Control Act (TSCA) requires chemical companies to research effects of new chemicals and notify the EPA before manufacturing them.
Step-by-step explanation:
The act that requires chemical companies to research the effects of new chemicals and notify the Environmental Protection Agency (EPA) before they are manufactured is the Toxic Substances Control Act (TSCA). None of the other options provided mandate this specific requirement. The Clean Air Act and the Clean Water Act are primarily focused on controlling air and water pollutants, respectively, while the Emergency Planning and Community Right-to-Know Act (EPCRA) involves community safety and emergency planning related to hazardous substances.