312 IAC 29-2-9 "Background radiation" defined

Sec. 9. "Background radiation" means radiation at the ground surface from: (1) cosmic sources; (2) non-technologically enhanced naturally occurring radioactive material, including radon, except as a decay product of source or special nuclear material; or (3) global fallout as it exists in the environment from the testing of nuclear explosive devices. The term does not include sources of radiation from NORM-contaminated equipment regulated under this article.