Answer: nervegas

AnswerCrossword Clue
NERVEGAS

Weapon outlawed by a 1993 agreement

NERVEGAS

Chemical warfare weapon

NERVEGAS

Outlawed weapon

NERVEGAS
Respiration retarder
NERVEGAS
VX, e.g.
NERVEGASBanned weapon of war
NERVEGASSarin, for one