Classification schemes for carcinogenicity based on hazard-identification have become outmoded and serve neither science nor society

•Cancer classification schemes based on hazard-identification such IARC and UN GHS are outmoded and inadequate to manage chemical risks.•Chemicals with many orders of magnitude difference in potency and modes of action are placed in the same category.•Unintended consequences of unnecessary health scares, economic costs, loss of beneficial products, and diversion of public funds.•Globally accepted problem formulation and hypothesis-based frameworks provide modern approaches based on hazard and risk characterization.•Call for an international initiative to develop a consensus on classification methodology for carcinogenicity assessment.

Abstract
Classification schemes for carcinogenicity based solely on hazard-identification such as the IARC monograph process and the UN system adopted in the EU have become outmoded. They are based on a concept developed in the 1970s that chemicals could be divided into two classes: carcinogens and non-carcinogens. Categorization in this way places into the same category chemicals and agents with widely differing potencies and modes of action. This is how eating processed meat can fall into the same category as sulfur mustard gas. Approaches based on hazard and risk characterization present an integrated and balanced picture of hazard, dose response and exposure and allow informed risk management decisions to be taken. Because a risk-based decision framework fully considers hazard in the context of dose, potency, and exposure the unintended downsides of a hazard only approach are avoided, e.g., health scares, unnecessary economic costs, loss of beneficial products, adoption of strategies with greater health costs, and the diversion of public funds into unnecessary research. An initiative to agree upon a standardized, internationally acceptable methodology for carcinogen assessment is needed now. The approach should incorporate principles and concepts of existing international consensus-based frameworks including the WHO IPCS mode of action framework.KeywordsClassification; Hazard characterization; Risk assessment; Carcinogenicity;
IARC; GHSAbbreviations
ACGIH, American Conference of Government Industrial Hygienists;
CoC, United Kingdom Committee on Carcinogenicity;
ECHA, European Chemicals Agency;
EFSA, European Food Safety Authority;
EPA, United States Environmental Protection Agency;
EU, European Union;
GHS, United Nations Global Harmonized System for Classification and Labelling;
IARC, International Agency for Research on Cancer;
IPCS, International Programme on Chemical Safety;
JMPR, Joint FAO/WHO Meeting on Pesticide Residues;
MOA, Mode of Action;
NCI, United States National Cancer Institute;
PMRA, Health Canada Pest Management Regulatory Agency;
WHO, World Health Organization

@ Classification schemes for carcinogenicity based on hazard-identification have become outmoded and serve neither science nor society: