CAS RN: 7803-51-2

Toxicity Summary

IDENTIFICATION AND USE: Phosphine is a colorless gas with a garlic-like odor. Phosphine is a fumigant, used indoors to control a broad spectrum of insects for non-food/non-feed commodities in sealed containers or structures. It is also used as a doping agent for electronic components, in chemical synthesis, and as an intermediate for the preparation of several flame retardants. HUMAN STUDIES: Direct contact with phosphine liquid may cause frostbite. Toxic exposures to phosphine have been documented as a result of grain fumigation, attempted suicide, and ferrosilicon decomposition. Potential symptoms of overexposure are nausea, vomiting, abdominal pain, diarrhea, thirst, chest tightness, dyspnea, muscle pain, chills, stupor or syncope, and pulmonary edema. A productive cough with fluorescent green sputum, acute dyspnea, and pulmonary edema may develop. Death may be preceded by tonic convulsions, which may ensue after apparent recovery. Death may occur after 1/2 to 1 hr of exposure at concentrations of 400 to 600 ppm. Serious effects may be produced by exposure to 5 to 10 ppm for several hours. Main histopathologic findings of fatal phosphine poisoning in the liver are fine cytoplasmic vacuolization of hepatocytes and sinusoidal congestion. Fumigant applicators had significantly increased stable chromosome rearrangements, primarily translocations in G-banded lymphocytes. Less stable aberrations included chromatid deletions and gaps but these were significantly increased only during the application season, and not at later time points. Exposure of human lymphocytes to phosphine (1.4 to 4.5 ug/L) for 20 mins yielded increased chromosome aberrations after 96 hr of lymphocyte culture, indicating that the expression of genotoxicity of phosphine is delayed. ANIMAL STUDIES: In rats, signs of exposure were typical of respiratory irritation and included hyperemia of the ears, salivation, lacrimation, face-pawing, and dyspnea. Rats exposed to phosphine repeatedly at 4 ppm for 4 hours daily on 9 of 12 days exhibited a slightly reduced weight gain, which returned to normal during the 14-day recovery period. Signs of mild respiratory irritation were observed in these animals. One study of animal teratogenicity with exposure as high as 4.9 ppm during days 6 to 15 of gestation in rats showed neither maternal toxicity nor developmental toxicity. In an in vitro cytogenetic assay with Chinese hamster ovary (CHO) cells, phosphine was positive at 2500 and 5000 ppm without metabolic activation. This resulted in a significant, but not dose-related increase in the frequency of cells with structural chromosome aberrations. Significant clastogenic effects were also noted at 2500 ppm with metabolic activation, but not at the highest dose tested (5000 ppm). Increased micronucleus (MN) induction in bone marrow polychromatic erythrocytes (PCE) was seen following subchronic exposure to phosphine in male mice at 5.0 ppm, and female mice at 2.5 and 5.0 ppm. In rats, MN elevation in bone marrow PCE and pulmonary alveolar macrophages was seen at 1.0 and 4.0 ppm, respectively, following subchronic exposure. ECOTOXICITY STUDIES: Three turkeys were exposed to phosphine at a concentration of 211 mg/cu m and 6 hens at 224 mg/cu m in an acute inhalation study. The turkeys exhibited apathy, restlessness, dyspnea, and tonic-clonic convulsions, and died after 68, 74, and 80 min, respectively. Hens exhibited tonic-clonic convulsions and died after an average of 59 min. Their organs were also congested with oxygenated blood. In rice seeds, phosphine has inhibitory effects on seed germination. In addition, phosphine exposure caused oxidative stress in the seeds.
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