3 at Nevada Test Site Exposed to Radiation

LAS VEGAS — Three Nevada Test Site workers were exposed to radiation last week when they re-entered a tunnel that was contaminated during the troubled Mighty Oak nuclear test April 10, the Department of Energy said.

Jim Boyer, a DOE spokesman, said all three received exposure doses that were within occupational safety guidelines.

One of the three was also exposed to radioactive iodine last month while re-entering the tunnel where the weapons-effects test was conducted, Boyer said.

A malfunction in the test left parts of the tunnel contaminated and damaged at least $20-million worth of equipment, the DOE announced earlier.

One of the workers exposed last month received 200 millirems of iodine-131 to the thyroid. Another worker received an exposure of 70 millirems. Radiation levels from the latest exposure showed the three workers last week received 625 millirems, 590 millirems and 375 millirems, respectively.

Millirem is the term used to describe the radiation dose to which a person is exposed. A chest X-ray is equivalent to about 20 millirems.

Occupational safety guidelines for radiation workers permit cumulative exposures of up to 3,000 millirems in any three-month period, with a maximum annual exposure of 5,000 millirems, Boyer said.

The three workers involved last week were wearing protective clothing with respirators and were in the contaminated area for less than five minutes, Boyer said.