In October, the deadly bacterium anthrax was found in mail sent to various news agencies, and to offices of the U.S. Congress. As a precaution, the U.S. Postal Service, with assistance from FBI and national public health experts, began irradiating mail to kill any potentially present anthrax spores.
On this page:
- Is my mail is being irradiated?
- What technology is being used to irradiate the mail?
- How does irradiation kill anthrax?
- Does mail that has been irradiated become radioactive?
- Are there changes to the mail after it has been irradiated?
- Have people complained of health problems from irradiated mail?
Is my mail is being irradiated?
Currently only mail to the White House, Congressional offices, and federal government offices in the 202-205 Zip Code exchanges is being irradiated. Irradiation is taking place at facilities in Ohio and New Jersey.
What technology is being used to irradiate the mail?
The Postal Service has selected electron beam technology to sterilize mail one half inch thick or less. Some powerful x-ray devices may also be used for certain types of packages.
How does irradiation kill anthrax?
Irradiation kills anthrax by shattering its DNA and other cellular components. The process for irradiating mail is the same process used to sterilize medical equipment.
During irradiation, an intense stream of electrons (or x-rays if x-ray technology is used) strikes the mail and any anthrax spores it may contain. The radiation dose is very high, about 56 kilo grays of radiation, which is approximately 2 million times more than a chest x-ray.
Does mail that has been irradiated become radioactive?
No. The process is roughly analogous to shining a flashlight on the mail - when the flashlight is turned off, mail does not glow, or radiate back the light it received.
Are there changes to the mail after it has been irradiated?
Yes. Irradiating mail at such high intensity creates new compounds, which can result in a different look, feel, and even smell. The potential health effects of these changes is unknown. Because of the intensity of the beam, mail often looks yellowed, and can become brittle. Book bindings may become brittle, and plastic may be discolored. Seeds, plants or other biological material will be sterile, and photographic film will be useless. Items such as gem stones may be altered, and computer disks, CDs, and some electronic equipment (like personal digital assistants) may be damaged.
Have people complained of health problems from irradiated mail?
Some postal and federal workers have complained of skin irritation and respiratory problems associated with exposure to irradiated mail. However, there are no established health effects from the mail, and investigations into a these complaints are ongoing.