Upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1 μg L-1 in water, or 1 μg m-3 in air.

Note: The interpretation of unit risk is as follows: if unit risk = 1.5 x 10-6 μg L-1, 1.5 excess tumors are expected to develop per 1 000 000 or 106 people if exposed daily for a lifetime to 1 μg of the chemical in 1 litre of drinking water.