Final answer:
The Drug Enforcement Administration (DEA) is the federal agency responsible for scheduling controlled substances under the CSA.
Step-by-step explanation:
The federal agency that is delegated authority for scheduling controlled substances is the Drug Enforcement Administration (DEA). The Controlled Substances Act (CSA), passed by Congress in 1970, empowers the DEA to regulate the manufacture, importation, possession, use, and distribution of certain substances. This agency classifies drugs into five distinct schedules based upon potential for abuse, medical value, and safety considerations. The DEA works closely with the Food and Drug Administration (FDA) to ensure drugs are appropriately scheduled. The FDA has its own set of responsibilities, such as regulating prescription and over-the-counter drugs, as well as a variety of other products listed in the Federal Food, Drug, and Cosmetic Act. However, when it comes to controlled substances and enforcing provisions of the CSA, it is the DEA that has primary responsibility.