2. Post office employee sorting parcels from overseas
3. Close-up of US mail bag
4. Various of international mail being sorted
5. Staff X-raying overseas parcel
6. Close-up of X-ray screen
7. Staff monitoring X-ray
8. Worker carrying mail sacks
9. SOUNDBITE: (Japanese)Yoshiaki Yoshiba, Section Chief, Tokyo International Post Office
"Handling mails that may contain anthrax is an unprecedented case. In the past, we had an incident where an explosive was contained in an envelope. After that incident, we introduced various ways of testing mail possibly containing explosives. But, this time, we are talking about anthrax. It is difficult to find out if it is inside mail unless it leaks from the package. Our staff is dedicated. Some may criticise us by saying that we are not aware of seriousness of the case, but I say that we are faithfully working on this."
Authorities confirmed on Tuesday that a white, powdery substance which leaked from a stamp on an airmail envelope posted in Japan did not contain anthrax.
Officials from the Ministry of Health, Labour and Welfare confirmed that the envelope, which was discovered by a postal worker in Fukushima Prefecture, 250 kilometres (150 miles) northeast of Tokyo, posed no threat to public safety.
The letter, which bore no sender's details, was addressed to Australia.
Meanwhile, Japanese postal authorities announced they have tightened checks on mail arriving from overseas to prevent possible bioterrorism following reports of mailed anthrax in the United States.
Since the weekend, postal workers have been required to X-ray any international mail that has no sender's name and address or is suspicious in appearance.
An official at the Tokyo International Post Office said that staff in charge of sorting overseas mail are making every effort to find any parcel containing dangerous substances, but admitted that it was a difficult task.