On Jun. 25, 1988, the U.S. Postal Service (USPS) proposed to ban mailings of microbe samples capable of causing diseases. Of 90,000 samples mailed in 1987, only three leaks – of innocuous microbes -were reported.

The action was being taken “to ensure the safety and health of . . . customers and employees,” the Postal Service announced. “The Postal Service is concerned that some customers are planning increased use of the mails for sending disease germs or hazardous toxins.”

No date was set to implement the new rules, which must go through a formal regulatory process before they can take effect.