2-Nitropropane exposure

Inhalation is the chief route of worker exposure. Comparative data from acute or subchronic inhalation exposures with rats (98) indicate that nitromethane and nitroethane are the least toxic of the nitroparaffins by this route and do not induce methemoglobin formation. The nitropropanes are less well tolerated 2-nitropropane is more toxic than 1-nitropropane and is more likely to cause methemoglobinemia. 

A comprehensive study of the tolerance of laboratory animals to vapors of 2-nitropropane was reported in 1952 (100). In a study pubHshed in 1979, rabbits and rats survived exposure to nitromethane for six months at 750 and 100 ppm, respectively, with no unexpected findings (101). Similarly, no compound-related effects were found for rabbits exposed to 2-nitropropane at 200 ppm or for rabbits or rats exposed at 27 ppm. Liver damage was extensive in male rats exposed at 207 ppm for six months, and hepatocellular carcinomas were observed. Subsequendy, the International Agency for Research on Cancer (lARC) found that there is "sufficient evidence" to conclude that 2-nitropropane causes cancer in rats but that epidemiologic data are inadequate to reinforce the conclusion in humans (102). The National Toxicology Program also concluded that it "may reasonably be anticipated to be a carcinogen" (103). 

Toxieology. 1-Chloro-l-nitropropane is an irritant of the eyes and mucous membranes. It is a pulmonary irritant in animals, and severe exposure is expected to cause the same effect in humans. 

Toxicology. 1-Nitropropane vapor is an irritant of the eyes in animals it also causes liver damage and mild respiratory tract irritation. There are no reports of systemic effects from industrial exposures. 

Griffin TB, Stein AA, Coulston F Inhalation exposure of rats to vapors of 1-nitropropane at lOOppm. Ecotox Environ Saf 6 268-282, 1982... 

Chronic health effects in humans from exposure to 2-nitropropane have not been adequately determined, although a retrospective mortality smdy of 1481 employees and former employees of a 2-nitropropane production facility with up to 27 years of exposure found no increase in cancer of the liver or other organs and no unusual disease mortality pattern. ... 

Hine CH, Pasi A, Stephens BG Fatalities following exposure to 2-nitropropane. J... 

Harrison R, Letz G, Pasternak G, et al Fulminant hepatic failure after occupational exposure to 2-nitropropane. Ann Int Med 107 466-468... 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), as many as 10 000 workers in the United States were potentially exposed to 2-nitropropane (see General Remarks). Occupational exposures may occur in its production and use as a solvent. 

The American Conference of Governmental Industrial Hygienists (ACGIH) (1997) has recommended 36 mg/m as the 8-h time-weighted average threshold limit value for occupational exposures to 2-nitropropane in workplace air. Similar values have been used as standards or guidelines in many countries (International Labour Office, 1991). 

Nitropropane was tested for carcinogenicity in two experiments in rats by inhalation exposure. Hepatocellular carcinomas were produced in one experiment and an increased incidence of hepatocellular nodules in the other. An inhalation study in rabbits was considered to be inadequate for evaluation (lARC, 1982). 

Rat. Male and female Sprague-Dawley rats, four to six days of age, were exposed by whole-body inhalation to concentrations of 0, 25, 40, 50, 80 and 125 ppm [0, 91, 146, 182, 292 and 456 mg/m3] 2-nitropropane (99% pure) for 6 h per day on five days per week for three weeks. One week later, a polychlorinated biphenyl (Clophen A50) was administered orally at a dose of 10 mg/kg bw tw ice per week for eight weeks. Thirteen weeks after the start of the experiment, the number of preneoplastic adenosine-5-triphosphatase-deficient foci in the liver was found to increase linearly with the exposure concentration, demonstrating the initiating activity of 2-nitropropane (Denk et al., 1990). 

Harrison et al. (1985, 1987) reported on two construction workers who were exposed to 2-nitropropane while applying epoxy resin coating. One man died 10 days after exposure from fulminant hepatitis, the other man had persistently elevated serum aminotransferase activity. Serum concentrations of 2-nitropropane on admission were 13 mg/L in the man who died and 8.5 mg/L in his co-worker. 

Inhalation exposure of male Sprague-Dawley rats to 2-nitropropane at air concentrations of 100 ppm [365 mg/m ] for 7 h per day on four consecutive days did not result in increased hepatic microsomal malonaldehyde content as a measure of lipid peroxidation, or increased levels of serum aspartate transferase or of glutamic oxaloacetic transaminase. Total hepatic glutathione was enhanced by 2-nitropropane treatment (Haas-Jobelius et al., 1992). 

Nitropropane is produced in low volume and occupational exposures occur primarily in its production and use as a solvent in inks, adhesives, paints and coatings. Exposures of the general population may occur in ambient air and water near industrial sites manufacturing or using 2-nitropropane, in cigarette smoke, and possibly from its solvent uses. 

Denk, B., Filser, J.G., Demi, E., Kessler, W., Shen, J. Oesterle, D. (1990) Dose-dependent emergence of preneoplastic foci in rat livers after exposure to 2-nitropropane. Arch. Toxicol., 64, 329-331... 

Haas-Jobelius, M., Coulston, F. Korte, F. (1992) Effects of short-term inhalation exposure to 1-nitropropane and 2-nitropropane on rat liver enzymes. Ecotoxicol. environ. Saf. 23,253-259... 

Toxicity and health effects Laboratory rats exposed to 2-nitropropane in high concentrations (207 ppm) developed adverse liver changes like hepatocellular hypertrophy, hyperplasia, necrosis, and liver carcinoma. It has been reported that prolonged exposure to concentrations of 20-45 ppm of 2-nitropropane caused nausea, vomiting, diarrhea, anorexia, and severe headaches among workers. Industrial workers handling 2-nitropropane for the application of epoxy resins to the walls of a nuclear power plant developed toxic hepatitis. - ... 

ACETATO MERCURIOSO (Spanish) (21908-53-2) A strong oxidizer. Violent reaction with reducing agents, acetyl nitrate, diboron tetrafluoride, disulfur dichloride, combustible materials, fuels, hydrazine hydrate, hydrogen peroxide, hydrogen trisulfide, hypophospho-rous acid, methanethiol, phospham. sodium-potassium alloy, sulfur, sulfur trioxide. Incompatible with alcohols, alkali metals, ammonium nitrate, diboron tetrafluoride, hydrazinium nitrate, hydrogen sulfide, nitroalkanes, rubidium acetylide, selenium oxychloride. Forms heat-, friction-, or shock-sensitive explosives with anilinium perchlorate, chlorine, phosphorus,. sulfur, magnesium, potassium, sodium-potassium alloy. May increase the explosive or thermal sensitivity of nitromethane, nitroethane, 1-nitropropane and other lower nitroalkanes, silver azide, hydrazinium perchlorate. Slowly decomposes on exposure to air. 

Nitropropane is being used extensively in the L.S..A. as a solvent. It was recently reported that prolonged exposure of rats to the action of 2-nitro-propane can produce cancer [2]. 

The well known hepatotoxicity of nitroaromatic compounds such as trinitrotoluene lends suspicion to the hepatotoxicity of the nitroparaffins." Nitromethane and nitroethane produce steatosis in animal models, but there is limited evidence of hepatotoxicity of these agents in humans." Evidence for the hepatoxicity of 2-nitropropane has been raised by case reports and case series of oeeupational fatalities in settings of severe exposure. In these cases the lack of appropriate industrial hygienic measures such as adequate ventilation, and personal protective equipment contributed to the severity of the exposures. " Autopsies of the fatal cases revealed hepatocellular necrosis and fatty infiltration of the liver. No significant evidence of hepatotoxicity has been demonstrated below the ACGIH TLV of 10 ppm. Medical surveillance of workers exposed to less than 25 ppm of 2-nitropropane have not shown alterations in liver chemistries. ... 

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