Answer to Question #3219 Submitted to "Ask the Experts"

Although this appears to be a straightforward question, the answer is complicated by the regulatory framework for radiation protection in the United States. The answer depends on the source of radiation that is exposing the radiation workers. I'll give a little background on the regulatory framework and then give you the best general answer to your question.

REGULATORY BACKGROUND

Permissible doses for radiation workers are set by the federal agency or state that has the responsibility for regulating the source of the radiation to the worker. Federal agencies with regulatory responsibilities include, for example, the Nuclear Regulatory Commission (NRC), the Department of Energy (DOE), the Occupational Safety and Health Administration (OSHA), and the Mine Safety and Health Administration (MSHA). Every state has a regulatory responsibility for sources of radiation exposure that are not covered by a federal agency, which includes radiation produced by machines such as x-ray machines and accelerators and naturally occurring radioactive material.

Although the actual radiation protection standards are set by the organization responsible for regulating the source of the radiation exposure, the Environmental Protection Agency (EPA) has the responsibility for issuing guidance to the federal agencies for radiation protection standards.

Sources of guidance and regulations are the EPA Federal Guidance issued by President Reagan on 27 January 1987, reproduced as Appendix A in Federal Guidance Report No. 11, the NRC worker protection regulations published in 10 CFR 20, the DOE regulations published in 10 CFR Part 835, OSHA regulations in 29 CFR 1910.1096, and the MSHA for Radon in Mines 30 CFR 57.5038.

Despite the many regulatory agencies involved in worker protection, they are all pretty consistent with the EPA guidance with the exception of OSHA, which still has radiation protection regulations based on old guidance, and MSHA, which is specific to radon exposure in mines. Therefore, the General Answer to your question, taken from the EPA guidance, is:

Exposure from external exposure combined with internal exposure is limited to an effective dose of 5 rem in a calendar year. In addition, exposure from internal exposure is limited to a committed organ dose of 50 rem to any organ from intake of radioactive material in a calendar year.

Exposure to the fetus of a pregnant radiation worker who has declared to her employer she is pregnant is limited to 0.5 rem for the pregnancy.

Keith Dinger, CHP