Is there an exposure hazard to people who handle mail which has been irradiated by the postal service? Can such mail contain residual activity? radioactivity?

Irradiating mail to destroy potential biological agents does not induce any radioactivity whatsoever in the mail (paper, paper clips, binder clips). The process would be the same as that used to kill harmful organisms in food and to sterilise surgical equipment. ) A simple analogy is that of having an X-ray taken, when of course the patient does not become radioactive. Internet research suggests that irradiation is only being carried out in the United States on mail destined for certain Government offices. It is not thought that the practice is currently in use in the United Kingdom. The US Postal Service stated "Irradiated mail is sterile and poses no hazard. It is not and cannot be radioactive".We've found no medical or scientific link to irradiated mail and health-related complaints, such as itching and sneezing... and... the mail ... meets federal guidelines for potential carbon monoxide and ozone emissions. Irradiated mail... creates more paper dust" (31 Jan 2002.)" While the mail and its contents do not become radioactive, any undeveloped photographic film carried in the mail would be spoiled by the large radiation field necessary to destroy harmful organisms. Anyone planning to implement mail irradiation would have to take this into account when setting up a programme. Any views expressed in this answer are not necessarily endorsed by the Society for Radiological Protection.