What level of federal regulation governs radiation safety in the United States?

The federal regulation that governs radiation safety in the United States primarily falls under the jurisdiction of the Nuclear Regulatory Commission (NRC). The NRC is responsible for regulating the use of nuclear materials and ensuring safety standards in the handling of radioactive substances. This includes overseeing the safety of radiation-producing devices and establishing regulations that protect public health and the environment from the potential hazards of radiation.

While the Environmental Protection Agency (EPA) plays a role in environmental health and safety, their focus is more on guidelines and standards related to broader environmental issues, including radiation exposure, rather than direct regulation of radiation safety across all sectors.

The FDA also has regulatory authority related to radiation safety, particularly in the context of medical devices and products that emit radiation. However, its purview is not as comprehensive in terms of all aspects of radiation safety as the NRC's.

The Centers for Disease Control and Prevention (CDC) primarily focuses on public health and disease control, including aspects related to radiation in the context of health impacts, but it does not carry regulatory authority over radiation safety standards.

Thus, the Nuclear Regulatory Commission is the principal federal body tasked with ensuring that radiation safety laws are enforced and that safety standards are adhered to, making it the correct answer for this question.