National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/14848

Target Organs and Levels of Evidence for TR-500

Toxicology and Carcinogenesis Studies of Naphthalene (CASRN 91-20-3) in F344/N Rats (Inhalation Studies)

Chemical (Study Title)
CASRN
Peer Review DatePrimary UsesRoute/Exposure LevelsStudy Laboratory
Naphthalene
91-20-3
05/18/2000Chemical intermediate, insecticides, repellants, antiseptic, vermicide, synthetic resins; in various commercial moth repellants and toilet bowl cleaners; topically in veterinary medicine. Prepared from coal tar. Associated with tobacco: reported either as a natural component of tobacco, pyrolysis product (in tobacco smoke), or additive for one or more types of tobacco products.Inhalation
R: 0, 10, 30, OR 60 PPM; 58/SEX/GROUP
Battelle Northwest Laboratory

Levels of Evidence

Male Rats: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Nasal Cavity: (RESPIRATORY EPITHELIUM) ADENOMA 0/49 6/49 8/48 15/48 (OLFACTORY EPITHELIUM) NEUROBLASTOMA 0/49 0/49 4/48 3/48
Non-Neoplastic Lesions
  • NASAL CAVITY: (OLFACTORY EPITHELIUM) ATYPICAL HYPERPLASIA; ATROPHY; CHRONIC INFLAMMATION; HYALINE DEGENERATION; (RESPIRATORY EPITHELIUM) HYPERPLASIA; SQUAMOUS METAPLASIA; HYALINE DEGENERATION; GOBLET CELL HYPERPLASIA; (GLANDS) HYPERPLASIA; SQUAMOUS METAPLASIA
Female Rats: Clear Evidence
TypeOrgan/Tissue (Lesion)
Neoplastic Lesions
  • Nasal Cavity: (RESPIRATORY EPITHELIUM) ADENOMA 0/49 0/49 4/49 2/49 (OLFACTORY EPITHELIUM) NEUROBLASTOMA 0/49 2/49 3/49 12/49
Non-Neoplastic Lesions
  • NASAL CAVITY: (OLFACTORY EPITHELIUM) ATYPICAL HYPERPLASIA; ATROPHY; CHRONIC INFLAMMATION; HYALINE DEGENERATION; (RESPIRATORY EPITHELIUM) HYPERPLASIA; SQUAMOUS METAPLASIA; HYALINE DEGENERATION; GOBLET CELL HYPERPLASIA; (GLANDS) HYPERPLASIA; SQUAMOUS METAPLASIA


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