What Kills Anthrax?

From the WebMD Archives

Oct. 30, 2001 -- Scared of anthrax in your mail? Use your head -- and not your iron or your microwave, experts advise.

First, use common sense. If you receive mail you suspect may contain anthrax, leave it alone. Follow the CDC's advice on what to do. (We've reprinted it below). Leave the decontamination to hazardous-materials experts.

"You are not supposed to be doing this on your own," warns anthrax expert Philip C. Hanna, PhD, professor of microbiology the University of Michigan, Ann Arbor.

What makes anthrax such a scary germ is that it travels in the form of spores. These nearly lifeless seeds hide inside a hard shell and can't be hurt by freezing cold or boiling heat. They wait for the right conditions to bloom into deadly bacteria.

The recent anthrax attacks have everybody's nerves on edge -- and have the rumor mills running full-speed. One rumor would have you iron all of your mail. Another would have you put it in the microwave. Would any of this work?

"Microwaving your mail won't do it," Hanna tells WebMD. "First of all, microwaves work by heating water, and spores have no water in them. It is like putting your empty coffee cup into the microwave -- it won't get hot. And even if you had water, spores can survive boiling."

So what about that hot iron? You could do more harm with it than good.

"The temperatures an iron gets to can kill spores. But you have to do it for a length of time that is more likely to burn your mail than kill the spores," Hanna says. "And if steam builds up inside the envelope, it can spray out and get the spores into the air."

If your mail isn't particularly suspicious, but you just don't want to deal with it, there is something you can do. "You can incinerate spores -- so if you want to burn your mail, it's OK," Hanna says.

Such a drastic step seems unnecessary. The U.S. Postal Service already is sending some mail to be sterilized by electron-beam machines. It's bought eight of the machines -- at $5 million each -- for delivery next month. There are plans to buy several hundred more. The machines were designed to sterilize medical devices and to get rid of germs in food products. Manufacturer Titan Corp. says the high-energy electrical beams can safely kill anthrax spores. Current plans call for the machines to be used on person-to-person and consumer-to-business mail -- which account for some 40 billion pieces of mail each year.

Other companies are getting into the act. The public/private Sandia National Laboratories -- operated by Lockheed Martin Co. for the U.S. Department of Energy -- has created an environment-friendly decontamination foam that kills anthrax spores.

"In the case of anthrax spores, one ingredient in this chemical cocktail essentially breaks the spores' armor, and then another chemical gets inside and kills it," Sandia spokesman John German tells WebMD.

One of the companies licensed to sell the product is Denver-based Modec Inc. The firm uses the Sandia decontaminant in several products intended for home and office use.

"One thing we've developed for the post office and the general public is a hand-washing solution," Modec CEO Brian Kalamanka tells WebMD. "The handwash can be used as a daily protective. We also sell a surface-cleaner spray made of the same product."

Do you really need this stuff? Hanna doesn't think so.

"Our lab uses simple bleach to decontaminate the benches where we work with anthrax," he says. "To kill spores in a small area -- like a desk -- use one part fresh bleach and nine parts water. Let it sit at least 30 minutes wet. And please, be careful not to get the bleach in your eyes, or on your skin where you have nicks or cuts or a hangnail."

Kalamanka admits that bleach works but notes that it is much harsher on the environment than the Sandia decontaminant. "And you can't use bleach to wash colored clothing," he notes.

Here are the CDC's latest guidelines for handling suspicious mail:

  • Don't shake the suspicious package or envelope. Don't sniff, touch, or taste any contents that may have spilled out.
  • Don't carry the suspicious mail around -- and don't have others take a look at it.
  • Put the suspicious package or envelope on the floor or someplace where it won't fall over.
  • Leave the area, closing doors behind you. Tell others about the suspicious mail, and keep anybody else from going into the area. If you can, shut off the ventilation system.
  • Wash your hands with plenty of soap and warm water.
  • If you're at work, report the incident to your supervisor, a security officer, or police. If at home, call the police or sheriff's department.
  • Make a list of the people who were in the room when the package or letter was opened. Include all people who may have handled this mail. Give copies of the list to police and to local public-health officials.

Mail is suspicious if it:

  • Was sent by someone you don't know;
  • Is addressed to someone no longer at your address;
  • Has a hand-written address with no return address or with a return address that can't be confirmed as legitimate;
  • Is lopsided or lumpy;
  • Is sealed with excessive amounts of tape;
  • Is marked "PERSONAL" or "CONFIDENTIAL";
  • Has excessive postage.