National Toxicology Program

National Toxicology Program

Testing Status of 5-Nitro-o-toluidine - 10475-F


CASRN: 99-55-8

Formula: C7-H8-N2-O2

Synonyms/Common Names

  • 2-Methyl-5-nitrobenzenamine

Known Uses

Dye intermediate

Chemical Properties

Toxicity Effects (HSDB)

Short-Term Toxicity

  • 14-Day (Dosed-Feed)  (C01843)  Completed 
    • Rats: F344/N; Mice: B6C3F1
  • 13-Week (Dosed-Feed)  (C01843)  Completed 
    • Rats: F344/N; Mice: B6C3F1

Long-Term Carcinogenicity

  • 2-Year (Dosed-Feed)  (C01843)  Report Complete 
    • TR-107 (NIH Number: 78-1357)  (Peer Review Approval 04/26/1978A )
      Bioassay of 5-Nitro-o-toluidine for Possible Carcinogenicity (CASRN 99-55-8)
    • Rats: F344/N; Mice: B6C3F1
    • Carcinogenesis Results
      • Male Rats Negative 
      • Female Rats Negative 
      • Male Mice Positive 
      • Female Mice Positive 

Genetic Toxicology

  • In Vitro Cytogenetics (CA/SCE)  (012878)  Completed 
    • Sister Chromatid Exchange Positive 
    • Chromosome Aberrations Positive 
  • Salmonella  (758929)  Completed 
    •  Positive 
  • Salmonella  (N-9370)  Completed 
    • Citation: Dunkel, V., Zeiger, E., Brusick, D., McCoy, E., McGregor, D., Mortelmans, K., Rosenkranz, H., and Simmon, V. Reproducibility of microbial mutagenicity assays. II. Testing of carcinogens and noncarcinogens in Salmonella typhimurium and Escerichia coli Environ. Mutagen. Vol. 7 (Suppl 5) (1985) 1-248
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.