Answer to Question #1723 Submitted to "Ask the Experts"
Category: Radiation Basics — Radiation Shielding
The following question was answered by an expert in the appropriate field:
Please provide information on methods used by the United States Postal Service in irradiating mail. What sources are used? What facilities are using irradiation to sterilize mail? What are the doses or general range of doses administered? What controls are needed to protect workers?
The United State Postal Service (USPS) is irradiating targeted mail destined for specific government offices in zip codes beginning with 202, 203, 204, and 205 at two contracted irradiation facilities in Lima, Ohio, and Bridgewater, New Jersey. These electron beam facilities are not capable of handling all the mail for these zip codes, so only those letters or parcels that fit specific criteria are irradiated. The USPS issued contracts in October 2001 to purchase additional irradiation equipment from Titan Corporation. Titan will operate and maintain the systems and the equipment will only be used for targeted mail. The electron beam irradiators deliver doses between 25-40 kilogray (kGy) to the mail, which is sufficient to render harmless any biological agent, including anthrax spores. Irradiation facilities produce very high dose rates so extraordinary safety systems are necessary to prevent anyone from entering the exposure room or chamber when radiation is produced. To ensure that employees and visitors are not exposed to even low levels of radiation produced at the facilities, very thick concrete or lead-lined walls shield the exposure rooms. The radiation levels are closely monitored at the facilities to ensure the complete safety of the workers. Here are some websites that provide additional information on mail irradiation:
Ken Kerns, CHP
Answer posted on 11 March 2002. The information and material posted on this website is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Website. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.
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