2-Chloro-N,N-bis(2-chloroethyl)ethanamine, also known as trichlormethine, tris(2-chloroethyl)amine is the organic compound with the formula N(CH2CH2Cl)3.

[1] As a vesicant the use and production is strongly restricted within the Chemical Weapons Convention where it is classified as a Schedule 1 substance.

Nitrogen mustards react via an initial cyclization to the corresponding quaternary aziridine salt.

The chemical is extremely toxic and may damage the eyes, skin, and respiratory tract and suppress the immune system.

HN-3 penetrates and binds quickly to cells of the body, but its health effects develop slowly.