International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 3)

For definition of Groups, see Preamble Evaluation.

Supplement 7: (1987) (p. 263)

CAS No.: 86-88-4
Chem. Abstr. Name: Thiourea, 1-naphthalenyl-

A. Evidence for carcinogenicity to humans (inadequate)

Cases of bladder tumours have been reported among rat catchers exposed to 1-naphthylthiourea (containing up to 0.2% 2-naphthylamine) [ref: 1].

B. Evidence for carcinogenicity to animals (inadequate)

1-Naphthylthiourea was tested for carcinogenicity in mice and rats by administration in the diet. The studies were considered to be inadequate for evaluation [ref: 2].

C. Other relevant data

No data were available on the genetic and related effects of ANTU in humans. It did not induce unscheduled DNA synthesis in rat hepatocytes in vitro. It was mutagenic to bacteria [ref: 3].

Overall evaluation

1-Naphthylthiourea (ANTU) is not classifiable as to its carcinogenicity to humans (Group 3).

Also see previous evaluation: Vol. 30 (1983)


1. Davies, J.M., Thomas, H.F. & Manson, D. (1982) Bladder tumours among rodent operatives handling ANTU. Br. med. J., 285, 927-931

2. IARC Monographs, 30, 347-357, 1983

3. IARC Monographs, Suppl. 6, 415-416, 1987


Last updated: 9 March 1998

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       Toxicological Abbreviations