More than two dozen manufacturing plants, including two breweries, several soft-drink bottling companies and an infant-formula plant, have been contaminated with radioactive particles from a device used to control static electricity, the Nuclear Regulatory Commission said yesterday.
The device, called an ionizing air gun and manufactured by 3M Co., was ordered withdrawn from food, drug and cosmetic plants over the weekend, more than two weeks after NRC inspectors confirmed that the air guns had leaked radioactive particles at Ashland Chemical Co. plants in Pennsylvania and Texas.
At a hastily called briefing for NRC commissioners, agency staffers said the action was taken after inspectors found contamination in other facilities using the device.
The plants include Ross Laboratories of Casa Grande, Ariz., which manufactures Similac infant formula; eight Coca-Cola bottling plants from California to Massachusetts; a Pepsi Cola plant in Tulsa, and Anheuser-Busch breweries in Jacksonville and St. Louis.
Dr. Frank Young, head of the Food and Drug Administration, said limited sampling had shown no evidence of contamination in any consumer products.
"I don't want the American people to be alarmed at this point of the investigation," he said. "The most important thing to do is to pull out all stops to see if products are contaminated."
According to NRC officials, most of the affected plants have been cleaned up and have resumed production. The products being tested are those that might have been manufactured while the plant was contaminated.
Ionizing air guns are widely used in manufacturing to reduce static electricity and remove dust from the air. Although nonradioactive devices are available, air guns using polonium 210 have become increasingly popular since being licensed by the NRC in 1964.
About 50,000 static eliminators using polonium are in use. The withdrawal order covers about 2,000 in use in plants regulated by the FDA.
The 3M device uses high pressure to force air past tiny ceramic spheres containing polonium 210. The contamination occurred when the spheres became dislodged and spewed out the front of the machine.
NRC officials said they are investigating evidence that 3M failed to report a high rate of failure for the devices, which are tested once a year. A review of the company's records showed that as many as one percent failed the annual test, the NRC said, but 3M reported a failure rate of 0.03 percent, apparently after discounting for devices damaged in use.
"In my view, on these type of devices you should have no failures," said Hugh Thompson, head of the agency's nuclear safety office.
NRC and FDA officials contend that the spheres pose relatively little health hazard because they are too large to be inhaled deeply into the lungs and are unlikely to be broken down by digestive acids if ingested.
Agency officials also discounted the possibility of product contamination, saying that the particles are relatively heavy and tend to fall to the floor near the air gun.
However, the problem was discovered when an Ashland Chemical customer found radioactivity in a shipment of sulfuric acid last November. It took more than two months to trace the radioactivity to the Ashland plant in Easton, Pa.