(epoxyethyl)benzene

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

Styrene oxide is known to be a genotoxic carcinogen; therefore testing on toxicity to reproduction has not to be performed according to REACH-VO Annex VIII 8.7.1 column 2 and Annex IX 8.7 column 2. Moreover, a relevant exposure to humans is excluded by handling styrene oxide exclusively under strictly controlled conditions according to Annex XI, article 3.

Short description of key information:
Further testing on fertility does not need to be conducted.

Effects on developmental toxicity

Description of key information

From available data there was no evidence for a teratogenic effect in rats or rabbits exposed to styrene oxide up to the lethal dose. 

Additional information

Styrene oxide is known to be a genotoxic carcinogen; therefore testing on toxicity to reproduction has not to be performed according to REACH-VO Annex VIII 8.7.1 column 2 and Annex IX 8.7 column 2. Moreover, a relevant exposure to humans is excluded by handling styrene oxide exclusively under strictly controlled conditions according to Annex XI, article 3.

In order to fulfil completeness requirements, studies on reproductive toxicity need not to be conducted; however available data should be reported. The only available study on reproductive toxicity of styrene oxide in mammals has been published by Sikov et al. 1986.

This study is summarised in the IARC 1994 report as follows:

Only one study of the reproductive toxicity of styene-7,8-oxide in mammals has been published (Sikov et al. 1986). Six groups of at least 31 Wistar rats were exposed by inhalation (whole body) to 100 ppm (490 mg/m³) or 300 ppm (1470 mg/m³) styene-7,8-oxide (purity, 99%) vapour for 7 h per day either during a three-week (five days/week) pre-gestational period, during a three-week (five days/week) pre-gestational period and through days 1-19 of gestation, or on gestational days 1-19 only. A control group was exposed to air during the whole period. Fetuses were examined on day 21. There was extensive mortality among rats that received prolonged exposure to 100 ppm; exposure to 300 ppm was discontinued after one day because of mortality. Maternal weight gain was reduced in all groups receiving 100 ppm. Exposure only prior to mating had no effect on mating or fertility. Gestational exposure decreased the number of animals pregnant at term by increasing pre-implantation loss of embryos; fetal weights and lengths were reduced, and the incidences of retarded ossification of the sternebrae and occipital bones were increased.

In the same study, groups of 23-24 New Zealand white rabbits were exposed by inhalation to 0, 15 or 50 ppm (74 or 245 mg/m³) (measured concentrations, 14.6 and 51 ppm) styene-7,8-oxide (purity, 99 %) vapour for 7 h per day on days 1-24 of gestation. Fetuses were examined on day 30. Maternal toxicity was observed at the highest dose only, resulting in increased mortality (19/24 versus 1/23 in controls and 4/24 at 15 ppm) and decreased food consumption and weight gain. There was no effect on the proportion pregnant at term, i.e. there was no marked pre-implantation loss, but there was an increase in post-implantation loss, with 0.25, 0.93 and 1.5 resorptions per litter in the control, low- and high-dose groups, respectively.

There was no effect on fetal weight, and no increase in the incidence of malformations was observed in either rats or rabbits.