X-Ray Leaks Expose Workers At Boeing Plant To Radiation

Boeing last month discovered that a protective window for monitoring an electron-beam welder at its Space Center East facility in Kent had been leaking X-rays - apparently since October 1996 - exposing at least a dozen workers to higher-than-allowed levels.

The X-ray exposure could mean an increased risk of cancer or cataracts in later life, although the degree of exposure was still being studied, the company said yesterday.

The workers included operators of the equipment, an engineer and a maintenance person, said Randy Bentley, director of safety, health and environmental affairs for Boeing's Information and Communications Systems division. They suffered no immediate ill effects and continue to work.

The company estimates the workers received a radiation dose of 25 to 50 rems per year. A rem is a measure of radiation absorbed by the body, and the maximum exposure allowed by the federal Occupational Safety and Health Administration is five rems per year.

It is difficult to determine health risk for people exposed to 40 or less rems per year, Bentley said.

State health experts and a company-hired radiation oncologist from Stanford University are investigating the exposure. The workers have been briefed about possible consequences.

The electron-beam welder at the Kent plant, where Boeing fabricates parts for various defense applications, is used to fuse two pieces of high-grade metal such as titanium.

Operators stand behind a radiation shield that has multipaned windows. One pane contains lead, which is a radiation barrier.

Last month, one of the windows was being replaced because of a crack, Bentley said. When the repair was tested on Feb. 24, inspectors discovered a radiation leak in an adjacent window, which apparently had been replaced but not tested near the time the welder was installed in 1996.

"The window might not contain lead, or it might not contain enough to attenuate the radiation," Bentley said. The welder was not being used while Boeing determines why the leak was not discovered when the window was installed.