Inhalation Toxicity of Sulfuryl Fluoride in Rats and Rabbits

Inhalation Toxicity of Sulfuryl fluoride in Rats and Rabbits.EISENBRANDT, D. L., AND NITSCHKE, K. D. (1989). Fundam Appl.Toxicol 12, 540–557. The inhalation toxicity of the structuralfumigant sulfuryl fluoride (SO₂F₂) was evaluated in rats andrabbits. Exposures for a preliminary 2-week study were 6 hr/day,5 days/week, to 0, 100, 300, or 600 ppm SO₂F₂ Nine often ratsat 600 ppm died or were moribund between the second and sixthexposures. Extensive kidney lesions were present in all ratsexposed to 600 ppm, whereas only minimal renal changes werenoted in rats at 300 ppm. Upper and lower respiratory tissueswere inflamed in the single rat that survived the 2-week exposureto 600 ppm. Rabbits exposed to 600 ppm SO₂F₂ were hyperactiveand one animal had a convulsion. Exposure to 300 or 600 ppmfor 2 weeks resulted in vacuolation and/or malacia in the cerebrumof all rabbits and most of these rabbits also had moderate inflammationof nasal tissues; a few rabbits at 600 ppm had inflammationof the trachea or bronchi. A subsequent 13-week study evaluatedrats and rabbits exposed to 0, 30, 100, or 300 ppm SO₂F₂ (337ppm TWA for rabbits). Rabbits initially were exposed to a highconcentration of 600 ppm; however, convulsions were noted intwo animals after nine exposures and the concentration subsequentlywas reduced to 300 ppm. Vacuolation and/or malacia were observedin the cerebrum of all rabbits at the highest concentration;one rabbit exposed to 100 ppm also had cerebral vacuolation.Rabbits at the highest concentration, as well as one rabbitexposed to 100 ppm, had inflammation of the nasal tissues. Ratsexposed to 300 ppm SO₂F₂ for 13 weeks had mottled incisor teeth,minimal renal effects, pulmonary histiocytosis, inflamma tionof nasal tissues, and cerebral vacuolation. Also, rats exposedto 100 ppm SO₂F₂ for 13 weeks had mottled teeth. fluoride toxicitywas suggested by mottled teeth in rats as well as elevationof serum fluoride levels in rats and rabbits exposed to SO₂F₂for 13 weeks. Although repeated exposure of rats and rabbitsto 100–600 ppm SO₂F₂ resulted in toxicity ofthe kidneys(rats only), brain, and respiratory system, no effects weredetected in animals exposed to 30 ppm for 13 weeks.