Radiation and Radiological Disasters. An area accessible to individuals, in which radiation levels exceed 500 rad (5 gray) in one hour at 1 meter from the source or from any surface that the radiation penetrates (see: 10 CFR 20.1003)
U.S. Nuclear Regulatory Commission (NRC), Full-Text Glossary, Washington, DC, USA 2014. http://www.nrc.gov/reading-rm/basic-ref/glossary/f ull-text.html, (Dzstr/ Disabl Mass Care - Amer) {826}