Does the USPS irradiate the mail?

Answer:
I've been researching this for the past hour and so far all I can come up with is that mail that is being sent to certain government offices is being irradiated. This was implemented during the 2001 anthrax attacks. The only issue I have with this answer is that most articles and materials only date back to 2002. I have not been able to find any information that is more recent.
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First answer by ID3478222817. Last edit by Rahm St. John. Contributor trust: 0 [recommend contributor recommended]. Question popularity: 1 [recommend question].