Police say nuclear density gauge stolen

A construction device that contains small amounts of radioactive material was stolen from a Henderson work site Tuesday afternoon and police are warning the public of its potential dangers.

City workers were using the nuclear density gauge, which resembles a large yellow shoebox with a calculator and handle, about 1:30 p.m. southwest of Horizon and College drives when it was stolen, police said. "They left it unattended for just a moment, and when they came back it was gone," said Todd Rasmussen, spokesman for Henderson police.

The gauge, last used at 618 Valley View Drive, doesn't pose an environmental contamination risk, but the technology can be dangerous if untrained people attempt to handle it, Rasmussen said.

Nuclear density gauges are used by construction workers to test the density of soil and asphalt, said Ed McGuire, quality control manager for Henderson's public works department. Each gauge is licensed through the state and its operators must receive special training, he said.

That doesn't mean the box is as dangerous as it might appear, McGuire said. The stolen gauge, a Troxler model 3440, is so sturdy it would be nearly impossible to dismantle and release the radioactive isotopes, Cesium 137 and Americium 241, he said. Inside the casing is a stainless steel cap, smaller than a thimble, that protects the isotopes.

The amount of radioactive material inside the gauge is so small that it is doubtful there is enough to significantly poison anyone, he said. "Someone might be able to expose themselves to a low dose of radiation, but that's about it," he said. "It would be like going into the dentist office and giving yourself multiple X-rays for fun. At some point that's considered unhealthy."

Government entities and numerous private material testing firms have been using the $7,000-$8,000 equipment for years, McGuire said.

"It's ... seen as a safe, convenient, efficient way to test materials," he added.

Typical radioactive exposure for gauge operators is between 100 and 200 millirem of radiation over a year; a normal medical chest X-ray is about 40 millirem, according to a 1994 U.S. Department of Transportation report.

McGuire did not know whether the workers violated any regulations by leaving the gauge unattended. There are rules regarding the transportation and storage of the nuclear density gauges, and the state of Nevada closely monitors their locations, he said.

The state does not require the police to notify the public if a nuclear density gauge is stolen but encourages such notification, McGuire said.

A lot of times when gauges go missing it's a case of someone finding it, not knowing what it is and moving it off the road so it's out of the way, McGuire said. "I hope that's the case here," he said.

Anyone with information should contact Las Vegas police at 828-8386, the Nevada State Health Division at 1-877-438-7231, or Henderson police at 267-4750.