Which regulation defines hazardous substance release according to the FWPCA?

The correct answer references 40CFR117.3, which specifically deals with the definition of hazardous substances and outlines what constitutes a release under the Federal Water Pollution Control Act (FWPCA). This regulation is critical for pollution responders because it provides clarity on what items are classified as hazardous substances and what scenarios qualify as a release, thus guiding compliance and responding efforts effectively.

Understanding this definition is essential for responders to ensure they are equipped to handle incidents involving hazardous materials appropriately. Responders need to recognize the implications of a release as defined by this regulation to activate the necessary protocols and reporting mechanisms outlined in the FWPCA.

The other choices relate to different aspects of environmental regulations, but they do not provide the specific definitions or regulations pertaining to hazardous substance releases under the FWPCA. Therefore, they would not serve the purpose of clarifying how to respond to or report concerning hazardous substance releases effectively.