Mail from N.J. postal facility to be irradiated

TRENTON, New Jersey (CNN) -- Mail from the U.S. Postal Service's regional processing center in Hamilton Township will be transported to an off-site facility later this week for irradiation, postal officials said Wednesday.

The three anthrax-contaminated letters sent to Senate Majority Leader Tom Daschle, the New York Post and NBC News were all postmarked in that facility, which remains closed.

At least 10 tractor-trailer trucks have been loaded and will depart Hamilton Township as early as Thursday morning for a sterilization facility about 80 miles south in Bridgeport, New Jersey. The postal service has awarded at least one contract to Ion Beam Applications, based in Oak Brook, Illinois, which operates the Bridgeport plant. IBA runs 22 other sterilization facilities in the United States.

In the radiation process, the mail is beamed with accelerated electrons, which kill bacteria within seconds. The hi-tech process is typically used by food-processing and medical supply companies to sterilize products before they are shipped. No gases or chemicals are used.

"Right now the mail is being taken out by a haz-mat team and loaded onto trucks," said postal spokeswoman Diane Williams. "I have counted 10 trucks so far, but we're not sure how many pieces of mail are on those trucks."

Williams also said that the high-speed electrons could damage certain items in the mail such as electronics, and may cause some plastics to become hard or brittle.

"The process could cause some paper discoloration and heat certain metal items, but magnetic stripping on credit cards should be fine," she said, reading from a list from IBA that outlined some of the potential radiation effects.