carcinogens any dose may result in a response whereas with non-carcinogens, toxic response only occurs above a threshold dose level. Cancer assessments utilize mathematical models to determine risk at low dose levels. Noncarcinogenic effects are considered to have dose thresholds and safety or uncertainty factors are used to provide a margin of safety. Historically, the Acceptable Daily Intake (ADI) procedure has been used to calculate permissible chronic exposure levels for humans based on non-carcinogenic effects. ADI is the