It is a reality that we live in a world where populations could be exposed to radiation or hazardous chemicals as a result of an accident, act of terrorism or a war. This exposure could cause serious health problems, sometimes within days or weeks, and may even lead to a latent health effect on humans, such as an increased cancer rate. Health professionals dealing with these cases therefore need methods to measure the effects of radiation and chemicals using molecular and cellular assays, and their possible short and long term consequences for potentially exposed members of a population at ris.