Ethylene

CAS RN:74-85-1

Toxicity Summary

IDENTIFICATION AND USE: Ethylene is a colorless gas. It is used for oxyethylene welding and cutting metals, as well as in the manufacture of alcohol, mustard gas, and many other organics. It is also used in manufacture of ethylene oxide (for plastics), polythene, polystyrene and other plastics. Ethylene is a plant growth regulator, which is used commercially to accelerate the ripening of various fruits. HUMAN STUDIES: Exposure to 37.5% ethylene for 15 min may result in marked memory disturbances. Humans exposed to as much as 50% ethylene in air, whereby the oxygen availability is decreased to 10%, experienced a loss of consciousness. Prolonged inhalation of 85% ethene in air is slightly toxic, whereas 94% in oxygen is fatal. Death is certain at 8% oxygen. In fatal human intoxication, ethylene affects the respiratory center of the brain and kills by suffocation. Postmortem analysis has revealed that the right side of the heart is full of blood, while the left side is empty. In workers chronically exposed, ethylene has been associated with a decrease in maximum arterial pressure, slower pulse, lengthened later period of the visual-motor response, increased thresholds of olfaction and hearing, and tension of the thermoregulatory apparatus. In eight people not occupationally exposed to ethylene, the DNA adduct 7-(2-hydroxyethyl)guanine was detected at a background level in peripheral lymphocytes. ANIMAL STUDIES: Mice were dosed by gavage with 3.75 mg/kg bw ethylene for 4 months. The treated animals displayed no changes in behavior or in body weight gain and oxygen consumption. Gross pathology examination revealed no changes in the relative weights or in the histological structure of the visceral organs. Inhalation exposure to 600,000 ppm continuously for 90 days in rats caused reduced food uptake and activity, peripheral leucopenia, decreased thrombocyte and erythrocyte count, and decrease in bone marrow cellularity. One-day-old and adult rats continuously exposed to 3 mg/cu m per day for 90 days exhibited hypertension, disruption of the subordination chronaxy, and decreased cholinesterase activity. Experiments proved ethylene to be metabolized in certain species, notably mice and rats, into the carcinogenic and mutagenic ethylene oxide. Administration of ethylene by head-only exposure revealed no potential for adverse reproductive effects in the rat. Ethylene was not found to be mutagenic with or without metabolic activation in Salmonella typhimurium strains TA98, TA1537, TA100, or TA1535. Rats and mice exposed 6 hr/day 5 days/week for 4 weeks to 40-3000 ppm ethylene did not have a significant increase in the frequency of micronucleated polychromatic erythrocytes in the bone marrow, when compared to the control group.
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