Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

One study is recorded for this endpoint and was chosen as a key study. The delayed contact hypersensitivity of sodium hypophosphite was assessed using the Maximization method of Magnusson and Kligman. This study was conducted in compliance with the principles of Good Laboratory Practices and performed according to the OECD guideline 406.

The induction phase has been realized both by intradermal route on day 1 (Test item at 10 % w/v in paraffin oil) and by cutaneous route on day 8 (Test item at 10% w/v in paraffin oil ) in 2 groups of guinea pigs: 5 males and 5 females for control group and 10 males and 10 females for treated group. The challenge phase was realized on day 22 by cutaneous application of Test item at 3% and 0.5% w/v in paraffin oil on two sites on the right flank (vehicle on the left flank). the cutaneous reactions were scored 24 and 48 hours after the challenge phase.

After the challenge application with the test item at 3 % in paraffin oil, a slight erythema was observed in 1/ 20 animals of the treated group at the 24 and 48-hour readings. No cutaneous reactions were recorded in the control group.

After the challenge application with the test item at 0.5 % w/v in paraffin oil, a slight erythema was observed in 3 and 1 out the 20 animals of the treated group at the 24 and 48-hour readings respectively.

The persistent cutaneous reactions observed in 4/20 animals of the treated group after the challenge application may be attributable to delayed contact hypersensitivity but as the cutaneous reactions were more confined to the 24 hour examination, they were more consistent with irritation than delayed contact hypersensitivity.

Therefore, the low incidence of cutaneous reactions observed in treated animals (20%) were considered as irritative response and the substance was not considered as a skin sensitiser.


Migrated from Short description of key information:
The potential of the substance to induce delayed contact hypersensitivity was investigated using the Maximization method of Magnusson and Kligman(OECD 406, GLP) . The test item was found to be non-sensitising.

Respiratory sensitisation

Endpoint conclusion
Additional information:
Migrated from Short description of key information:
There is no reported case of respiratory sensitisation in humans.

Justification for classification or non-classification

Skin sensitisation:

In accordance with column 2 of REACH annex VII point 8.3, the murine Local Lymph Node Assay (LLNA) (OECD guideline 429) is the first-choice method for in vivo testing of skin sensitisation. However a reliable guinea-pig maximization test was already available (Rees, 1991).

According to the results of the guinea-pig maximization test and the criteria laid down in EU regulation (EC) n°1272/2008 (CLP) and EU Directive 67/548/EEC, the substance is not classified for skin sensitisation.