Answer:
Laws That Keep Us Safe
With certain limited exceptions, the federal law in Title 18 United States Code 1716 (18 U.S.C. 1716) declares it a crime to mail anything that may kill or injure persons or harm property. Persons violating the statute may be subject to fines, imprisonment, or other severe penalties.
The Postal Service has established rules prescribing preparation and packaging conditions under which certain hazardous materials, which are not “outwardly of their own force dangerous or injurious to life, health, or property,” may be mailed. Because these rules are very limited, most hazardous materials are prohibited from mailing.