In deciding whether to visit ground zero at Trinity Site, the following information may prove helpful.
Radiation levels in the fenced, ground zero area are low. On an average the levels are only 10 times greater than the region's natural background radiation. A one-hour visit to the inner fenced area will result in a whole body exposure of one-half to one milliroentgen (mrem).
To put this in perspective, a U.S. adult receives an average of 90 milliroentgens every year from natural and medical sources. For instance, the Department of Energy says we receive between 35 and 50 milliroentgens every year from the sun and from 20 to 35 milliroentgens every year from our food. Living in a brick house adds 50 milliroentgens of exposure every year compared to living in a frame house. Finally, flying coast to coast in a jet airliner gives an exposure of between three and five milliroentgens on each trip.
Although radiation levels are low, some feel any extra exposure should be avoided. The decision is yours. It should be noted that small children and pregnant women are potentially more at risk than the rest of the population and are generally considered groups who should only receive exposure in conjunction with medical diagnosis and treatment. Again, the choice is yours.
At ground zero, Trinitite, the green glassy substance found in the area, is still radioactive and must not be picked up.