U.S. Postal Service to Irradiate Mail

WASHINGTON, DC, October 24, 2001 (ENS) - The U.S. Postal Service will begin irradiating mail as of November 1 in an effort to wipe out deadly anthrax bacteria, Postmaster General Jack Potter announced today. The irradiation is part of a tough new set of measures Potter has introduced to protect postal workers and the public from anthrax in the mail.

"This new technology won't be cheap, but we are committed to spending what it takes to make the mail safe," Potter said. Irradiation, which consists of bombardment of the mail with electrons, is already being used to kill bacteria in some foods.

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U.S. Postal Service employee sorts mail delivered to California's Superior Court of Alameda County courthouse postal station. (Photo courtesy Superior Court of Alameda County)
The new postal safety measures are in response to anthrax mail contamination that has been found on Capitol Hill, at an off-site White House mail screening facility, and in a New Jersey mail sorting center. Contaminated mail has sickened at least a dozen people and claimed the lives of two postal workers at the Brentwood mail sorting center near Washington, DC.

American flags at all postal facilities are flying at half staff beginning today, until after the funerals of the two dead postal workers, Joseph Curseen and Thomas Morris.

Potter said there are several other employees who may have anthrax. "We in the Postal Service are at war," he said. "A war against terrorism. Our job is to win that war." An investigation to find the source of the anthrax is underway with a million dollar reward offered for information leading to the arrest and conviction of the perpetrators.

President George W. Bush assured the nation that he has not been contaminated with anthrax. Strict security precautions have been in place at the White House since September 11, and all environmental tests at the White House have come back negative.

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President George W. Bush meets with Director of the Office of Homeland Security Tom Ridge (left), Postmaster General John Potter, and president of the National Association of Letter Carriers Vince Sombratto (not shown) in the Oval Office Tuesday. (Photo by Tina Hager courtesy the White House)
The mail screening facility where anthrax bacteria was found on a mail slitting machine is located at a military installation several miles from the White House. It has been closed for further testing and decontamination. All employees at the site are being tested for exposure to the disease, as are mail workers in the White House complex itself.

Speaking to reporters Tuesday, the President said he cannot link the anthrax incidents with the September 11 terrorist plane strikes on the World Trade Center and the Pentagon.

"Well, we don't have any hard evidence, but there's no question that anybody who would mail anthrax with the attempt to harm American citizens is a terrorist. And there's no question that al Qaeda is a terrorist organization. ... So it wouldn't surprise me that they're involved with this. But I have no direct evidence."

The House and Senate are both in session this week following last week's anthrax scare during which the House was closed for environmental testing and several Senate offices were closed.

At a press briefing on Capitol Hill, Senate Majority Leader Tom Daschle said that many of the Senate office buildings that were closed following the October 15 discovery of an anthrax-laced letter addressed to him will be opened in the "not too distant future." But, he said, "we may have to quarantine and keep sealed my office and the mail room," where the contaminated letter was found.

The Foundation for Food Irradiation Education (FFIE), a radiation processing industry association, says bacteria such as anthrax that are present in or on mail can be destroyed by irradiation treatment.

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Vincent Sombrotto is president of the 312,500 member National Association of Letter Carriers, AFL-CIO. (Photo courtesy NALC)
The U.S. Postal Service delivers about 208 billion pieces of mail each year, 90 percent of it to and from businesses. The FFIE says there are many points in the mail processing system at which the application of radiation might be useful - the local post office, central distribution centers, points of delivery to sensitive locations such as government or news organizations, and points of delivery from mass mailing locations such as catalog warehouses.

Three different irradiation technologies exist using three different kinds of rays: gamma rays, electron beams and x-rays, according to a fact sheet issued by the Centers for Disease Control, a federal agency.

Gamma rays are produced either by a radioactive form of the element cobalt (Cobalt 60) or of the element cesium (Cesium 137). When not in use, the radioactive element is stored in a pool of water which absorbs the radiation. To irradiate food or some other product, the source is pulled up out of the water into a chamber with massive concrete walls that keep any rays from escaping.

The electron beam is a stream of high energy electrons, propelled out of an electron gun, a larger version of the device in the back of a TV tube that propels electrons into the TV screen, making it light up. An e-beam generator can be simply switched on or off. No radioactivity is involved. Some shielding is necessary to protect workers from the electron beam, but not the concrete walls required to stop gamma rays.

The newest technology is X-ray irradiation. A beam of electrons is directed at a thin plate of gold or other metal, producing a stream of X-rays coming out the other side. Like cobalt gamma rays, X-rays can pass through thick materials, and require heavy shielding for safety. Like e-beams, the machine can be switched on and off, and no radioactive substances are involved. Four commercial X-ray irradiation units have been built in the world since 1996.

It will take time to design and install irradiation systems for use in postal facilities application, and postal service officials have not indicated which irradiation method will be used. Meanwhile, Potter said, the post office is changing its cleaning methods to protect against anthrax.

"We are changing the procedures we use to clean mail sorting equipment," he said. "We are no longer using air gusts to scatter dust and other particles, and instead are vacuuming equipment in a way that absorbs dust and other particles. We are directing postal facilities to use stronger, antibacterial cleaning chemicals as part of their routine maintenance."

Postal workers are being provided with masks and gloves to wear if they wish. Field command centers have been set up so employees can notify the centers if they seek admission to a hospital so postal officials can quickly identify any pattern of medical problems that might develop.

Anthrax information from the Centers for Disease Control is online at: http://www.bt.cdc.gov/