The nitrogen mustards are cytotoxic chemotherapy

Chemotherapy

Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

 agents similar to mustard gas. Although their common use is medicinal, in principle these compounds can also be deployed as chemical warfare

Chemical warfare

Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...

 agents. Nitrogen mustards are nonspecific DNA alkylating agents. Nitrogen mustard gas was stockpiled by several nations during the Second World War, but it was never used in combat. As with all types of mustard gas, nitrogen mustards are powerful and persistent blister agent

Blister agent

A blister agent, or vesicant, is a chemical compound that causes severe skin, eye and mucosal pain and irritation. They are named for their ability to cause severe chemical burns, resulting in painful water blisters on the bodies of those affected...

s and the main examples (HN1, HN2, HN3, see below) are therefore classified as Schedule 1 substances within the Chemical Weapons Convention

Chemical Weapons Convention

The Chemical Weapons Convention is an arms control agreement which outlaws the production, stockpiling and use of chemical weapons. Its full name is the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction...

.