Michigan Administrative Code
Department - Environmental Quality
Air Quality Division
Part 2 - AIR USE APPROVAL
Section R. 336.1231 - Cancer risk assessment screening methodology
Current through Vol. 24-04, March 15, 2024
Rule 231.
(1) The initial risk screening level (IRSL) and the secondary risk screening level (SRSL) shall be determined as follows:
Where: Inhalation unit risk = Additional lifetime cancer risk occurring in a population in which all individuals are exposed continuously for life to a concentration of 1 microgram per cubic meter of the chemical in the air they breathe.
1 x 10-6 = An upper bound lifetime cancer risk of 1 in 1,000,000.
1 x 10-5 =An upper bound lifetime cancer risk of 1 in 100,000.
(2) The following provisions apply to derivation of the inhalation unit risk:
(3) An annual average time period shall be used for the IRSL and SRSL.