Principles of Risk Assessment and Management

Carcinogenicity evaluations by the International Agency for Research on Cancer (lARC) serve as the international benchmark for classifying chemicals as carcinogens. lARC assesses and classifies chemicals according to the following scheme (Illing 2001 lARC 2006)  

A list of chemicals assessed by lARC is available at the following URL http // monographs.iarc.fr/ENG/Monographs/allmonos90.php . 

CHAPTER 3 HAZARD AND RISK ASSESSMENT OE CHEMICAE CARCINOGENICITY 

On a biennial basis, the U.S. NTP issues the congressionally mandated Report on Carcinogens (RoC). This document provides a list of known human carcinogens and substances that are reasonably anticipated to be human carcinogens, along with a brief profile for each substance. A summary of the classification criteria used in the 11th RoC is provided below (NTP 2008)  

Historically, risk assessment for noncancer endpoints has been based on the identification of a no observed adverse effect level (NOAEL) from a toxicity study with an animal model. The NOAEL is then divided by appropriate uncertainty factors to take potential inter- and intraspecies differences in response into account. However, this approach does not take into account the size of the toxicity study or the shape of the dose-response curve. The benchmark dose (BMD) approach has been suggested as an alternative to a NOAEL (Crump 1984). A BMD is a dose or concentration that produces a predetermined change (e.g., 10% or 1 standard deviation) in response rate of an adverse effect (called the benchmark response or BMR). A BMDL is the statistical lower confidence limit on the dose or concentration at the BMD. The BMD and BMDL are calculated using mathematical dose-response models, which make appropriate use of sample size and the shape of the dose-response curve (EPA 2009b, 2000a). The BMDL is like a NOAEL (i.e., as a point of departure) and is divided by an appropriate composite uncertainty factor to derive a reference value. 

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