IARC carcinogen update.

We recently published an article in which we presented a list of occupational carcinogens (Siemiatycki et al. 2004), based on the International Agency for Research on Cancer (IARC) Monographs Program. Our review covered Volumes 1-83 of the IARC Monographs. However, because the IARC Monograph Program is ongoing, the list of occupational carcinogens will need to be periodically updated. Since we completed our article, there have been three Monograph meetings that addressed substances that can be classified as occupational; therefore, we would like to notify readers of some important changes in the list of occupational carcinogens. Table 1 shows summary information about occupational substances and mixtures that were recently evaluated by IARC as human carcinogens (group 1), probable human carcinogens (group 2A), or possible human carcinogens (group 2B). As we did in our earlier article (Siemiatycki et al. 2004), we added to the IARC evaluations our assessment of the main occupations in which the agent may be found and the target organ for carcinogenicity.

Volume 86 focuses on cobalt in hard-metals and cobalt sulfate, gallium arsenide, indium phosphide, and vanadium pentoxide (IARC, in press a) In our article (Siemiatycki et al. 2004), cobalt and cobalt compounds were listed as Group 2B human carcinogens.

In IARC's recent evaluation (IARC, in press a), cobalt metal with tungsten carbide is classified in Group 2A, whereas cobalt metal without tungsten carbide, cobalt sulfate, and other soluble cobalt(II) salts remain in Group 2B. Three substances for which there were no previous IARC evaluations have now been evaluated and classified: gallium arsenide is classified as a Group I human carcinogen, indium phosphide as a Group 2A (probable) human carcinogen, and vanadium pentoxide as a Group 2B (possible) human carcinogen (IARC, in press a).

Volume 87 (IARC, in press b) updates the prior evaluations on inorganic and organic lead compounds, which were included in Volume 23 (IARC 1980) and in Supplement 7 (IARC 1987). Previously, lead and inorganic lead compounds were classified in Group 2B, whereas organic lead compounds were classified in Group 3. The most recent IARC evaluation results in an upgrading of inorganic lead compounds to Group 2A; organic lead compounds remain in Group 3 (IARC, in press b). The Working Group, however, noted that part of the organic lead is metabolized into ionic lead, which would be expected to present the same toxicity as inorganic lead.

In Volume 88, formaldehyde was upgraded from a Group 2A (probable) to a Group 1 human carcinogen (IARC, in press c; Cogliano et al. 2005). The other two substances covered by this monograph, 2-butoxyethanol and 1-tert-butoxy-2-propanol, are evaluated as Group 3 (not classifiable).

The authors declare they have no competing financial interests.

REFERENCES

Cogliano VJ, Grosse Y, Baan RA, Straif K, Secretan MB, El Ghissassi F, and the Working Group for Volume 88. 2005. Summary of IARC Monographs on Formaldehyde, 2-Butoxyethanol, and 1-tert-Butoxy-2-Propanoh Environ Health Perspect 113:1205-1208.

IARC. 1980. Some Metals and Metallic Compounds. IARC Monogr Eval Carcinog Risk Chem Hum 23.

IARC. 1987. Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42. IARC Monogr Eval Carcinog Risk Chem Hum(suppl 7).

IARC. 2004. Some Drinking-Water Disinfectants and Contaminants, Including Arsenic. IARC Monogr Eval Carcinog Risk Hum 84.

IARC. In press a. Cobalt in Hard-metals and Cobalt Sulfate, Gallium Arsenide, Indium Phosphide and Vanadium Pentoxide. IARC Monogr Eval Carcinog Risks Hum 86.

IARC. In press b. Inorganic and Organic Lead Compounds. IARC Monogr Eval Carcinog Risks Hum 87.

IARC. In press c. Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxy-2-propanol. IARC Monogr Eval Carcinog Risks Hum 88.

Siemiatycki J, Richardson L, Straif K, Latreille B, Lakhani R, Campbell S, et al. 2004. Listing occupational carcinogens. Environ Health Perspect 112:1447-1459.

Marie-Claude Rousseau

INRS-Institut Armand-Frappier,

Universite du Quebec

Montreal, Quebec, Canada

E-mail: [e-mail]

Kurt Straif

International Agency for Research on Cancer

Lyon, France

E-mail: [e-mail]

Jack Siemiatycki

Universite de Montreal

Montreal, Quebec, Canada

E-mail: [e-mail]

Table 1. Substances and mixtures that have been evaluated
by IARC as human carcinogens and that are occupational
exposures, based on Monograph Volumes 84-90.

                           Occupation or industry in which
Substance or mixture       the substance is found (a)

Cobalt metal with          Production of cemented carbides
  tungsten carbide         (hard-metal industry), tool
                           grinders; saw filers;
                           diamond polishers
Cobalt metal without       Miners; production of alloys;
  tungsten carbide         processing of copper
                           and nickel ore; glass and
                           ceramic production;
                           welders of cobalt-
                           containing alloys
Cobalt sulfate and other   Electroplating and ceramic
  soluble cobalt(II)       industries
  salts
  Gallium arsenide         Production; microelectronics
                           industry (integrated
                           circuits and optoelectronic
                           devices)
Indium phosphide           Production, microelectronics
                           industry (integrated
                           circuits and optoelectronic
                           devices)
Vanadium pentoxide         Ore refining and processing;
                           chemical manufacturing
                           industry; maintenance of oil-fired
                           boilers and furnaces
Inorganic lead             Lead smelters, plumbers,
  compounds                solderers; occupations in
                           battery recycling smelters,
                           production of lead-acid
                           batteries; printing press
                           occupations, pigment production;
                           construction and demolition
Formaldehyde               Production, pathologists; medical
                           laboratory technicians;
                           plastics; textile and plywood industry

                                                  IARC          IARC
Substance or mixture           Site(s)       classification   Monograph

Cobalt metal with              Lung (b)            2A            86
  tungsten carbide
Cobalt metal without           Uncertain           2B            86
  tungsten carbide
Cobalt sulfate and other       Uncertain           2B            86
  soluble cobalt(II)
  salts
  Gallium arsenide             Uncertain         1 (c)           86
Indium phosphide               Uncertain         2A (d)          86
Vanadium pentoxide             Uncertain           2B            86
Inorganic lead                 Lung (b)            2A            87
  compounds                   Stomach (b)
Formaldehyde                Nasopharynx (e)        1             88
                             Leukemia (b)
                           Nasal sinuses (b)

(a) Not necessarily an exhaustive list of occupations/industries
in which this agent is found; not all workers in these
occupations/industries are exposed. The term "production"
is used to indicate that this substance is man-made
and that workers may be exposed in the production
process. (b) We judged that the evidence for
an association with this site was suggestive.
(c) In reaching an overall evaluation of Group 1, the
working group noted the potential for gallium arsenide
to cause cancer through releases of a small amount of
its arsenic, which behaves as inorganic arsenic at the
sites where it is distributed. Arsenic and arsenic compounds
have been evaluated as IARC Group 1, carcinogenic to humans.
For arsenic in drinking water, the most recent ARC evaluation
of arsenic [Volume 84; (ARC 2004)], there was sufficient
evidence in humans that arsenic causes cancers of the urinary
bladder, lung, and skin; the evidence for cancers of the
liver and kidney was limited. (d) Absence of data on cancer
in humans; the final evaluation for carcinogenicity was
upgraded from 2B to 2A based on evidence of carcinogenicity
in experimental animals. (e) The evidence was sufficient.