Classification of Carcinogens

The complete list of agents and chemical substances evaluated by the I ARC and their classifications is available in lARC Monographs, volumes 1-98.  

The National Toxicology Program (NTP) has listed chemical substances for carcinogenicity under two categories  

Cancer-Causing Chemical Substances and Occupation Affected 

Benzidine and cadmium dyes Beryllium and compounds Chromium pigments Fertilizers and pesticides Organic solvents 

Generally, workplace exposures to chemical substances are considered to be at higher levels than for public exposures. Material safety data sheets (MSDSs) should always contain an indication of carcinogenic potential. The Report on Carcinogens (RoC) is an informational scientific and public health document first ordered by the U.S. Congress in 1978. This report has identified agents, substances, mixtures, or exposure circumstances that may pose a hazard to human health by virtue of their carcinogenicity. 

TABLE 24.2. International Agency for Research on Cancer (IARC) Classification of 

Source IARC, http //monographs.iarc.fr/ENG/Preamble/currentb6evalrationale0706.php. 

TABLE 24.3. Internationa] Agency for Research on Cancer (IARC) List of Agents, Substances, Mixtures or Exposure Circumstances Known to Be Carcinogenic to Humans 

Bis(chloromethyl)ether and chloromethyl methyl ether (technical grade) 

Estrogen therapy, postmenopausal Estrogen-progesterone postmenopausal therapy Estrogen-progesterone oral contraceptives Estrogens, nonsteroidal 

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TABLE 5.21 Classification of Carcinogenicity of Chemicals According to the International Agency on Research on Cancer... 

Greim H (ed) Occupational Toxicants, Vol 13, critical data evaluation for MAK values and classification of carcinogens. Commission for the investigation of health hazards of chemical compounds in the work area, Bisphenol A, p 49. New York, VCH, 1999... 

Greim H, Reuter U Classification of carcinogenic chemicals in the work area by German AlAK Commission current examples for the new categories. Toxicology 166 11-23, 2001... 

Greim. H, Occupational Toxicants Critical Data Evaluation of MAK Values and Classification of Carcinogens. Vol, 14. John Wiley Sons, Inc., New- York, NY, 2000. 

Mechanistic information is most relevant for the evaluation and classification of carcinogens. As indicated below, a carcinogenic effect, which is induced by a specific mechanism that does not involve direct genotoxicity, such as hormonal deregulation, immune suppression, cytotoxicity, the detailed search for the underlying... 

It has been reported recently that the existing systems of classification of carcinogens are a matter of worldwide discussion. However, there is agreement that any classification should distinguish between genotoxic and nongenotoxic chemical substances. For details refer to the literature. The close association between prolonged use of... 

The World Health Organization, International Agency for Research on Cancer, has evaluated the data for aniline and has placed aniline in its group 3 classification of carcinogenicity , that is, aniline is not classifiable as to its carcinogenicity to humans. 

DFG (1998) Deutsche Forschungsgemeinschaft. Occupational Toxicants, Critical Data Evaluation for MAK Values and Classification of Carcinogens, Greim H. ed., Vol. 12, pp. 223-236. Wiley-VCH, Weinheim. 

Dr. G. M. Williams analyzed animal carcinogenicity from the standpoint of the definition of a carcinogen, based upon an operational description, and the classification of carcinogens. 

For classification of carcinogens in categories 1 and 2, the danger symbol T with the danger identification toxic and the R-phrases 45 or 49 have to be used. R 49 Hmits usage in which there is an inhala-tive cancer risk of the respiratory tract caused from dust, fibers, or H-quid aerosols. Typical examples are asbestos, chromium(Vl) compounds, and cadmium chloride. 

In accordance with the evidence available, different classes for chemical carcinogens have been developed by health authority organizations. Examples ofthe classification of carcinogenic solvents are presented in Table 20.1.3. 

Classification of carcinogens. NIOSH continues to review its approach to classifying carcinogens and establishing recommended exposure limits (RELs). 

Table 15.2 shows the classification of carcinogenic aromatic dangerous substances. 

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