2, 4-Toluene diisocyanate cancer

Hagmar L, Stromberg U, Welinder H, et al. 1993. Incidence of cancer and exposure to toluene diisocyanate and methylene diphenyldiisocyanate a cohort based case-referent study in the polyurethane foam manufacturing industry. Br J Ind Med 50(11) 1003-1007. 

In the Montreal case-control study carried out by Siemiatycki (1991) (see monograph on dichloromethane in this volume), the investigators estimated the associations between 293 workplace substances and several types of cancer. Isocyanates were one of the substances, and it was stated that the most common form in this study was toluene diisocyanates. The main occupations to which isocyanate exposure was attributed in this study were motor vehicle refinishers, motor vehicle mechanics and foundry workers. Only 0.8% of the study subjects had ever been exposed to isocyanates. For most types of cancer examined (oesophagus, stomach, colon, rectum, pancreas, prostate, bladder, kidney, skin melanoma, lymphoma), there was no indication of an excess risk due to isocyanates. For lung cancer, in the population subgroup of French Canadians (the majority ethnic group in this region), based on 10 cases exposed at any level, the odds ratio was 2.2 (90% CI, 0.9-5.3). [The interpretation of the null results has to take into account the small numbers and presumably low exposure levels. Workers had multiple exposures.]... 

Experimental studies have shown that dermal application of toluene diisocyanate can elicit pulmonary sensitization. International Agency for Research on Cancer lists toluene diisocyanate as an animal carcinogen (from studies using gavage administration). 

Nevertheless all spray foams have the crucial disadvantage that they contain isocyanates, which are critical with respect to toxicological and enviromental impUcations [8]. Monomeric isocyanates like TDI (toluene diisocyanate) or MDI (methylenediphenyl diisocyanate) are even suspected of causing cancer [8, 9]. Although these foams are used even by nonprofessionals, to date there exist no suitable, less endangering substitutes. 

A chemical that causes an allergic reaction—that is, can evoke an adverse immune response in a person. See also sensitizer below. Example toluene diisocyanate, CAS 584-84-9 A chemical that causes cancer in humans or animals—indicating that it has potential to cause cancer in humans. Example benzidine, CAS 92-87-5 A chemical that burns under most conditions once ignited, but it does not ignite and burn as easily as a flammable (see below). Example aniline, CAS 62-53-3 A gas stored under pressure—under this pressure it might be in a gaseous or liquid state but under normal pressure it is a gas. Example propane, CAS 74-98-6 A chemical that causes destruction of living tissue at the site of contact. Example sodium hydroxide, CAS 1310-73-2... 

Toluene-2,4-diisocyanate caused tumor in the liver and pancreas in test animals. There is snfficient evidence of its carcinogenicity in animals. Its cancer-causing activity in humans has not been established. 

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