Potassium thiocyanate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Aqueous solutions of thiocyanates salts of ammonium, sodium or potassium, are fully dissociated. Consequently, results from dermal sensitisation studies with sodium thiocyanate or ammonium thiocyanate are fully applicable for the evaluation of potassium thiocyanate as well when effects are solely based on the SCN- anion.

 

Ammonium thiocyanate was found not to be sensitising following a maximisation test according to OECD 406. However, the study was found to be of limited validity as specifically concentrations applied for the induction phase were not high enough.

 

In an LLNA assay with sodium thiocyanate the SI values calculated for the substance concentrations 10, 25 and 50% were 1.6, 2.7 and 1.5 respectively. Since there was no indication that the test substance elicits an SI≥3, nor shows a dose response relation when tested up to 50%, Sodium thiocyanate was considered not to be a skin sensitizer.

Migrated from Short description of key information:
A LLNA study with NaSCN, indicates that thiocyanates are not sensitizing.

Justification for selection of skin sensitisation endpoint:
Only available study sufficient for classification purposes, based upon read-across.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

There is no information on respiratory sensitisation. However, no concerns are expected.

As chemical respiratory sensitisers also elicit positive results in predictive tests for contact sensitisation, a negative outcome for dermal sensitisation is also predictive for non respiratory sensitisation of the substance.

Additionally, the likelihood for exposure via inhalation and thus becoming sensitised to Sodium thiocyanate is very low as result to the exposure via inhalation route.The vapour pressure is extremely low (< 1.33 x 10-8 Pa) and thus does not present any potential for inhalation exposure due to volatilization of the salt. Furthermore thiocyanates are very hygroscopic (see granulometry). Inhalable particles are not available and will also not be formed during handling and use of the substance.

Migrated from Short description of key information:
As suggested in REACH guidance R7a. (R.7.3.5 Information and its sources on respiratory sensitisation), the negative results on skin sensitisation from an adequately performed appropriate test can also be regarded as lacking the potential to cause allergic sensitisation of the respiratory tract.

Justification for selection of respiratory sensitisation endpoint:
Low likelihood of exposures.

Justification for classification or non-classification

Based on the negative result from an LLNA study with sodium thiocyanate, potassium thiocyanate also need not be classified as a skin sensitizer.

As suggested in REACH guidance R7a. (R.7.3.5 Information and its sources on respiratory sensitisation), the negative results on skin sensitisation from an adequately performed appropriate test can also be regarded as lacking the potential to cause allergic sensitisation of the respiratory tract.