Regarding enforcement of regulations, if the contents of an 
article presented for mailing, as described by the mailer or 
otherwise, are determined to be nonmailable, the article is 
refused. An article also may be refused if the customer fails to 
demonstrate that potentially hazardous material is properly 
packaged. The Postal Service also can report hazardous materials 
packaging failures and related information when packages break 
open or fail in mail processing through our hazardous materials 
incident reporting system. However, the Postal Service is unable 
to screen all parcels to determine what hazardous materials are 
being mailed and whether they are properly identified and 
packaged according to regulations, because of legal and practical 
constraints. Under existing law a search warrant is required to 
open First-Class Mail, the class at which most hazardous material 
would be mailed. As a practical matter, packages containing 
hazardous materials are too small a portion of the mailstream to 
be detected by random screening procedures. Hazardous materials 
may account for anywhere from one in 100,000 to one in one 
million pieces anywhere in the mailstream. Sampling of the 
mailstream, therefore, would not yield sufficient observations of 
packages containing hazardous materials to be informative. 
Mr. Chairman, this completes the Postal Service's outline of 
customers' concerns and other matters related to the handling of 
etiologic materials in the mail. We will be pleased to respond 
to your questions. 
[396] 
Recombinant DNA Research, Volume 13 
