For carcinogens, the estimated exposure will be multiplied by the appropriate Cancer Slope Factor or Unit Risk to derive an estimate of the potential Incremental Lifetime Cancer Risk (ILCR) associated with that exposure (Health Canada 2004). The ILCR is derived as:
ILCR = Exposure (μg/kg/d) x Cancer Slope Factor (μg/kg/day)-1
Where pathway-specific slope factors or unit risks exist, the risks via inhalation and the risks via oral + dermal exposure should be estimated separately. In other cases, the cancer risks posed by simultaneous inhalation/dermal/oral exposure can be estimated.
Cancer risks will be considered “essentially negligible” where the estimated ILCR is 1-in-100,000 (≤ 1 x 10-5) (Health Canada 2004).
If the ILCR is greater than 1 x 10-5, the risk assessment should either be refined and/or risk management measures should be taken.
You can calculate an ILCR value using the Risk Calculation Tools.