about Epidemiology & the department

Epidemiology academic information

Epidemiology faculty

Epidemilogy resources

sites of interest to Epidemiology professionals

Last Updated

29 Jul 2003

Source: Baltimore Sun, July 23, 2003

Post office unveils anthrax detector

After a year of testing, officials say technology in place to prevent biohazard

By Scott Shane, Sun Staff

As technical challenges go, it's a doozy: With 202 billion pieces of mail posted each year, design a machine that will detect a single letter containing anthrax spores so tiny that thousands could be piled on the period at the end of this sentence.

And make sure the contraption isn't triggered by the countless, harmless particles that spew from envelopes as they speed through mail processing machines.

After more than a year of tests at Baltimore's main post office, U.S. Postal Service officials believe they have what it takes: a system that will prevent the deaths, illnesses, panic and disruption caused by the anthrax-laced letters mailed in 2001.

"We've developed the technology to make sure this will never happen again," said Don Crone, the agency's manager of mail processing protection systems.

Postal officials led reporters yesterday on the first tour of the Biohazard Detection System installed in Baltimore's processing center on Fayette Street, where 1,842 workers handle 5 million pieces of mail a day.

A maze of conveyor belts sped envelopes through the cavernous building, as machinery rumbled and postal workers hurried to transfer trays of mail. On each of the 11 high-speed cancellation machines through which mail enters the building, biodetectors drew off a constant stream of air and directed it to an automated testing unit.

"This way we don't have to worry, 'Did anthrax go through the machine?'" said Charles Thomas, a 13-year veteran, as he used rubber gloves and pliers to pull jammed mail from a cancellation machine. "I think it will give us a warning."

The letters mailed to news media organizations and two U.S. senators in September and October 2001 killed five people and sickened at least 17 others. Two of the dead were postal workers at the Brentwood mail processing center in Washington, now renamed in honor of the victims, Joseph Curseen Jr. (case 16) and Thomas Morris Jr (case 15).

By spreading deadly anthrax spores through postal centers and government offices, the letters forced congressional and federal offices -- including the Supreme Court -- to close temporarily. It also caused massive disruption of mail delivery.

The bill for cleaning up the hardy invisible spores has been estimated at several hundred million dollars, including $100 million for Brentwood alone. That center is now free of spores and might be reopened by Thanksgiving, postal officials said yesterday.

Northrop Grumman Corp.'s Baltimore-based electronic systems division developed the Biohazard Detection System under a contract initially valued at $3.7 million, according to the company. Postal centers in 14 other cities received machines this month for further testing. Under a new $175 million contract with Northrop Grumman, the postal service will install equipment in all 283 mail processing centers next year.

Postal officials acknowledged that the new system is not perfect. For now, it can detect only anthrax, though there are plans to improve it to detect other dangerous germs that bioterrorists might mail.

Also, it's unlikely to detect anthrax sent in packages, which don't go through the "pinch rollers" that squeeze air from letters during cancellation. But for the same reason, anthrax in a package is unlikely to spill out and expose large numbers of people.

If a letter contains anthrax, however, officials are confident that some spores will be pulled off as the mail passes under a hood on its way into the cancellation machine.

The spores, along with other solids in the air, are then concentrated in a sterile water solution. Next, the solution is automatically injected into a cartridge loaded with chemicals for a sophisticated test called PCR, or polymerase chain reaction, which detects the DNA of anthrax. The device should be able to distinguish the dangerous Bacillus anthracis even from its closest cousins, Crone said.

A PCR test takes less than an hour, and mail remains in the processing center for at least several hours. So, although an anthrax letter might still contaminate much of the building -- officials are working on improved air filters to reduce the potential spread -- there should be no danger of the letter leaving the center undetected.

If the machine detects anthrax, it will automatically send e-mail alerts to designated officials, who in turn will use fire alarms to alert the work force. When employees gather at designated spots in the parking lot, they will be given advice on decontamination and antibiotic treatment, officials said.

Jim Nagy, an occupational health specialist for the Postal Service, said the 2001 attack taught two lessons about anthrax. "It's hard to kill," he said, "but it's also highly treatable if we catch it in time. And this machine makes sure we catch it in time."

A major concern of the scientists who tested the system at Fort Detrick, Aberdeen Proving Ground and the Johns Hopkins Applied Physics Laboratory was eliminating false alarms that could result in major disruption of mail delivery, force unnecessary evacuations and close processing centers while samples are retested.

The machines are likely to encounter a long list of suspicious substances.

Since the anthrax attacks, the Postal Service has coped with more than 18,000 incidents involving powder, possible explosives and other suspected terrorist materials. Many were deliberate hoaxes, and none turned out to contain a bioterror agent, Crone said.

Another unknown is the possibility that in cattle country, where cows regularly contract anthrax, traces of the bacteria may be naturally present in the air, though presumably not in dangerous amounts. That's why one of the biodetection machines was installed this month in the postal center in Midland, Texas.

"But we haven't had a single false positive so far," Crone said.