Airborne radioactivity areas under OSHA's radiation rule

October 6, 1992
Mr. Richard A. Schreiber
Georgia Radon Program
DHR Environmental Health
[Recipient address omitted]
Dear Mr. Schreiber:
We regret the delay in responding to your letter of March 19, to Ms. Cynthia Wolff, Atlanta Regional Office, requesting clarification of the Occupational Safety and Health Administration's (OSHA) Ionizing Radiation Standard, 29 CFR 1910.1096.
Regarding the definition of "airborne radioactivity area" in 1910.1096(e)(4)(i)(a-b), an area is to be posted as an airborne radioactivity area if an employee is in the area for 40 hours during a week and is exposed to radioactive levels in excess of 25 percent of the concentration specified in column 1 of Table 1 of Appendix B to 10 CFR 20.
For example, an airborne radioactivity area would exist in an area where an employee worked for 40 hours per week and the radon-222 concentration in the area exceeded [25] picocuries per liter. An airborne radioactivity area requires employee monitoring and restricted access to the area ~~by the public.~~
[This document was edited on 06/24/2003 to strike information that no longer reflects current OSHA policy. See 12/23/2002 DeWitte Letter.]
We will answer your specific questions in the order that you asked them.

1. Does this regulation apply to all businesses not specifically excluded now?
   The standard applies to all employers covered by the Occupational Safety and Health Act, except agriculture employers, who (1) possess, use, or transfer sources of ionizing radiation, or (2) possess, use, or transport radioactive material not licensed by the Nuclear Regulatory Commission (NRC).
2. Is it the intent of this regulation to apply the definition of "airborne radioactivity area" to areas with airborne Naturally Occurring Radioactivity Material (NORM)?
   29 CFR 1910.1096 covers NORM. Accordingly, the definition of airborne radioactivity area applies to areas that contain airborne NORM.
3. Is it the intent of the regulation to use inhalation values of the referenced 10 CFR 20 since the regulation has been revised?
   The inhalation values incorporated in 29 CFR 1910.1096 are those that were in 10 CFR 20 in 1971 when OSHA promulgated the standard.
   We appreciate the opportunity to clarify these matters for you.
   Sincerely,
   Ruth McCully, Director
   Office of Health Compliance Assistance

[Requester letter reproduced on OSHA page; omitted here.]