Water supplies may be deliberately contaminated with chemical or biological agents. This may be done by aerial attack or by sabotage on the ground by introducing the agent into the water source at the intake or treatment works, a raw-water or treated water reservoir, or a transmission main by injection. Such introduction could be effected by suborning the works staff and sabotaging the control and detection procedures. The rapid dissemination of such agents to the unsuspecting population could have devastating effects.
Estimates suggest that in a large industrial city in a temperate climate, one kg of Botulin A toxin could lead to the death of 28,000 people, while 10 kgs of LSD could incapacitate the same number.