United States Nuclear Regulatory Commission - Protecting People and the Environment
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Lethal dose (LD)

The dose of radiation expected to cause death to 50 percent of an exposed population within 30 days (LD 50/30). Typically, the LD 50/30 is in the range from 400 to 450 rem (4 to 5 sieverts) received over a very short period.

Page Last Reviewed/Updated Thursday, November 20, 2014