Evaluation of the Embryotoxicity of Hydrazine in Rats

NIOSH skin notation (SK) profile: hydrazine [CAS No. 302-01-2].

“…No specific data were identified that estimated the degree of absorption of hydrazine in humans following dermal exposure. However, sufficient data were identified from absorption studies in rabbits [Army Center 1949;Keller et al 1981Keller et al , 1984, acute toxicity studies in rabbits and guinea pigs [Army Chemical Center 1949; Rothberg and Cope 1955], and a reproductive toxicity study [Keller et al 1982] following dermal exposure to conclude that hydrazine is absorbed through the skin, is systemically available, and is toxic (causing central nervous system effects and a body weight decrease). There is no evidence from studies of humans that hydrazine is corrosive to human skin.…”

“…It should be noted that the dose that elicited the response was not quantified. In animals, maternal toxicity (evidenced by decreased body weight at 5 mg/kg or more) and a significant increase in number of resorptions per litter (at 50 mg/kg) were observed in pregnant rats exposed to a single dose of hydrazine (0-50 mg/kg; 95% purity) on gestation day 9 [Keller et al 1982]. There was no other evidence of fetotoxicity or teratogenicity (no significant changes in fetal body weight or increase in fetal abnormalities) in this single-dose study.…”

“…Lowestobserved-adverse-effect levels (LOAELs) of 5 mg/kg (for the dams) and 50 mg/kg (for developmental effects) were observed. The single-dose dermal LOAEL of 5 mg/ kg (for maternal effects) observed by Keller et al [1982] suggests that the critical dermal effect level for prolonged exposure is likely to be lower than 1000 mg/kg/day, the level which identifies chemical substances with the potential for repeat-dose, subchronic, or chronic dermal toxicity [NIOSH 2009]. Therefore, hydrazine is considered potentially systemically toxic following dermal exposure.…”

“…The dose used in this study was 10 mg/day/animal, corresponding to approximately 430 mg/kg/day, assuming a United States Environmental Protection Agency (USEPA) [1988] default average chronic body weight of 0.023 kg for Balb/c mice used in this study. Keller et al 1982] following dermal exposure are sufficient to conclude that hydrazine is absorbed through the skin, is systemically available, and is toxic (causing central nervous system effects and a body weight decrease). Therefore, hydrazine is assigned a SK: SYS (FATAL) notation.…”