Registration Dossier

Administrative data

Description of key information

The acute toxicity of Sodium hypophosphite was assessed using:
- an acute oral toxicity test in rats (method comparable to EPA 870.1100 and OECD 401 guidelines, GLP compliance not stated in the study report)
- an acute dermal toxicity test in rabbits (method comparable to EPA 870.1200 and OECD 402 guidelines, GLP compliance not stated in the study
report)
Sodium hypophosphite is of low acute toxicity following oral exposure:
The oral LD50 was found to be greater than 5000 mg/kg bw in male rats. the oral LD50 in female rats was found to be lower than 5000 mg/kg bw and should be included in the 2000 -5000 mg/kg bw acute toxic class.
Sodium hypophosphite is of low acute toxicity following dermal exposure:
The dermal LD0 was determined to be equal or greater than 2000 mg/kg bw in rabbits.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
2 000 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
2 000 mg/kg bw

Additional information

Acute oral toxicity

One study is reported for this endpoint and was chosen as a key study.

The acute oral toxicity was performed using a methodology similar to EPA OPPTS 870.1100 and OECD 401guidelines.There were no information in the report about GLP compliance.

Sodium hypophosphite was administered at dose-levels of 2000 and 5000 mg/kg bw to male rats. Females rats received only the highest dose.

Negative control groups receiving water only were included in the study.

there were no deaths in the controls and in the 2000 mg/kg bw dosed group while 3 out of 10 males and 6 out of 10 females were found dead at the 5000 mg/kg bw dose. At necropsy, red lungs and stomachs filled with a clear watery fluid were reported in the animals found dead. In the treated surviving animals, mild depression and piloerection were observed from day 1 to day 2 and from day 1 to day 3 in the 2000 mg/kg bw and 5000 mg/kg bw dosed groups respectively . Body weight gain was similar to controls and no apparent abnormalities were observed at necropsy.

Under the experimental conditions of this study, the oral LD50 in male rats was higher than 5000 mg/kg and the oral LD50 in female rats should be included in the 2000 -5000 mg/kg bw acute toxic class.

Acute dermal toxicity

One study is reported for this endpoint and was chosen as a key study.

The acute dermal toxicity was performed using a methodology similar to EPA OPPTS 870.1200 and OECD 402 guidelines.There were no information in the report about GLP compliance.

Sodium hypophosphite was applied to the skin of five males and five females at the dose-level of 2000 mg/kg bw. One group of 2 males and 2 females acts as a control group.

Neither mortality nor systemic clinical signs were observed during the study. A moderate erythema and a mild to moderate oedema were observed on removal of the dressing and cleared within 24 hours. The body weight gain of the animals was not affected by treatment compared to controls. No apparent abnormalities were observed at necropsy in any animal.

Under these experimental conditions, the dermal LD0 of Sodium hypophosphite was equal or higher than 2000 mg/kg in rabbits


Justification for classification or non-classification

According to the criteria laid down in EU regulation (EC) n° 1272/2008/EC (CLP) and EU directive 67/548/EEC, sodium hypophosphite is not classified for acute toxicity.