Which of the following is not a regulation enforced by the EPA?

The selection of Hazardous Waste Operations as not being a regulation enforced by the EPA is appropriate because Hazardous Waste Operations and Emergency Response (HAZWOPER) is a standard set by the Occupational Safety and Health Administration (OSHA) and pertains to worker safety during hazardous waste operations and emergency response. In contrast, the other three options are regulations directly enforced by the Environmental Protection Agency (EPA).

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) establishes a framework for the cleanup of hazardous waste sites and is specifically managed by the EPA. The Resource Conservation and Recovery Act (RCRA) governs the management of hazardous waste, including its generation, transportation, treatment, storage, and disposal, directly under EPA regulations. The Toxic Substances Control Act (TSCA) aims to ensure the safety of chemicals and is also an EPA-led regulation concerning chemical substances.

In a practical context, while training on Hazardous Waste Operations is essential for compliance during hazardous operations, it does not classify as a regulation within the purview of the EPA's enforcement. Thus, understanding that HAZWOPER is an OSHA standard clarifies why this option is correctly identified as not being a regulation enforced by the EPA.