Nasal passages, inhalation toxicity

Toxicology. The acute oral and dermal toxicity of naphthalene is low with LD q values for rats from 1780—2500 mg/kg orally (41) and greater than 2000 mg/kg dermally. The inhalation of naphthalene vapors may cause headache, nausea, confusion, and profuse perspiration, and if exposure is severe, vomiting, optic neuritis, and hematuria may occur (28). Chronic exposure studies conducted by the NTP ia mice for two years showed that naphthalene caused irritation to the nasal passages, but no other overt toxicity was noted. Rabbits that received 1—2 g/d of naphthalene either orally or hypodermically developed changes ia the lens of the eye after a few days, foUowed by definite opacity of the lens after several days (41). Rare cases of such corneal epithelium damage ia humans have been reported (28). Naphthalene can be irritating to the skin, and hypersensitivity does occur. 

Larson et al. (1996) investigated the ability of intermediate exposure to chloroform vapors to produce toxicity and regenerative cell proliferation in the nasal passage of male and female B6C3Fi mice. Groups of 8 animals of each sex were exposed to 0, 0.3, 2, 10, 30, or 90 ppm chloroform via inhalation for 6 hours a day, 7 days a week for 3, 6, or 13 weeks additional groups of 8 animals of each sex were exposed for... 

The nasal passages have an olfactory function, but with regard to inhaled toxicants they have primarily a defensive function and form the initial defensive barrier against inhaled... 

SAFETY PROFILE Moderately toxic by ingestion. Inhalation of vapor can cause irritation to nasal passages and conjunctiva, optic neuritis, narcosis, retching, and death from pulmonary irritation. Industrial fatalities have occurred only with exposure to high concentrations. Flammable liquid. Ver dangerous fire hazard when exposed to heat or flame can react vigorously with oxidizing materials. Explosive in the form of vapor when exposed to heat or flame. 

Buckley and coworkers (1985) have investigated the inhalation toxicity of dimethy-lamine in F-344 rats and B6C3F1 mice. Animals exposed to 175 ppm for 6 h/day, 5 days/week for 12 months showed significant lesions in the nasal passages. Rats developed more extensive olfactory lesions than did mice. The study indicated that olfactory sensory cells were highly sensitive to dimethylamine. Even at a concentration of 10 ppm, the current threshold limit value, the rodents developed minor lesions from exposure. 

Klonne and associates (1987) have reported a 1-year inhalation toxicity study of chlorine in rhesus monkeys. Exposure to 2.3 ppm chlorine caused ocular irritation during the daily exposures. Histopathological changes were observed in the respiratory epithelium of the nasal passages and trachea. These changes, however, were mild at the foregoing level of exposures. Monkeys were less sensitive to chlorine toxicity than were rats. 

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