A sealed device used to check whether radiation detectors are working properly at Brookhaven National Laboratory leaked a small amount of radioactivity last month, lab authorities said. There was no threat to public health or the environment, but the lab has halted some operations while it investigates.
The radioactivity was later found on two employees, in a parking lot and private vehicle, and in one of the facility's buildings, the lab said. The lab is reviewing policies, procedures and training programs.
"Even the leak of a small amount of radiation is unacceptable," George Goode, assistant director for environmental safety and health at the lab on eastern Long Island, said Monday. "We are treating this very seriously."
The lab announced in a statement Friday that it shut down all radiological operations following the Sept. 28 leak. The leak was first reported Monday by the Long Island Business News.
Two employees were checking radiation detectors when a "sealed source" device containing a small amount of cesium-137 stored inside a lead container tipped over in the employees' pickup truck as they made their rounds, Goode said. The device was described as a small brass rod, about 8 inches long and a half-inch across.
"At first the employees didn't think anything of it," Goode said. Several hours later, a small amount of radiation was detected in the pickup truck.
The workers contacted supervisors, who expanded their investigation and found low levels of radiation on the men, in the parking lot where they left the truck and in a building where they worked.
A small amount _ 3.4 millirems _ was also found on one of the worker's hands; Goode said the acceptable limit for radiation on a hand is 50,000 millirems. One of the workers later went to lunch in a colleague's private vehicle, and a trace of radiation was found on a floor mat in that car, the official said.
"Still, that is unacceptable to us," Goode said.
According to the U.S. Environmental Protection Agency, exposure to radiation from cesium-137 results in increased risk of cancer. It is found in very small amounts in soil and water as a result of atmospheric fallout. It can last in the environment for decades.
The Brookhaven Lab in Upton is run by the U.S. Department of Energy. It conducts research in physical, biomedical and environmental sciences, as well as in energy technologies and national security. About 3,000 employees work at the lab, about 400 with radiological materials, spokesman Peter Genzer said.
Seven Nobel Prizes have been awarded for discoveries made at the lab, according to its website.
Adrienne Esposito, executive director of the Long Island-based Citizens Campaign for the Environment, who has monitored activities at Brookhaven for more than a decade, said the facility has worked to improve safety.
"This is very surprising because the lab has had a very good safety record," she said. "The overall culture at the lab has changed, and their safety record has been very good for several years."
The lab was criticized after a leak of tritium, a radioactive chemical, from a spent fuel pool was discovered in the ground in 1998. It had gone undetected for 12 years, but Esposito said officials have since worked to improve safety and communicate better with the public.
Lab officials could not immediately explain the 10-day delay in announcing the leak. They said that an investigating committee has been formed to review all policies and procedures and officials at the Energy Department have been notified. An agency spokesman did not immediately comment.
"This is a bit unusual, because these devices are made to contain radioactive material. We're taking a look at our practices," Goode said.
Officials are checking with colleagues throughout the Energy Department to determine whether other sealed devices have had problems. The devices are tested twice a year; the one in question passed inspection most recently in July. Officials were still trying to determine the manufacturer of the device that spilled.
"They're called sealed for a reason," Goode said.