Registration Dossier

Administrative data

Description of key information

The systemic toxicity of cyanides is sufficiently high that acute toxicity and possibly lethality occur before irritation can develops.  KCN can be converted to HCN on moist skin and in the eye, and is absorbed via the skin and eye.

Key value for chemical safety assessment

Additional information

The systemic toxicity of cyanides is sufficiently high that systemic intoxication and death are likely to occur before the development of inflammatory irritation effects on the skin or eye. Testing for skin and eye irritation is not feasible, due to the high acute toxicity of HCN derived from KCN. The amount of test material required in a standard skin and eye irritation study (500 and 100 mg/animal, respectively) is considerably above the level of systemic toxicity of cyanide. For example, for HCN, the dermal LD50 in rabbits is 2.34 mg/kg bw in abraded skin, and the ocular toxicity is 1.04 mg/kg bw. Recommended precautions for handling of HCN include respiratory protection to prevent lung inhalation, and barrier protection for eye and skin.


Effect level: empty Endpoint conclusion: Adverse effect observed

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Classification as a skin or eye irritant is not appropriate as no reliable data exists. The extremely high acute toxicity of HCN and its salts indicates that it is classified as an acute toxicant, with appropriate warnings to avoid skin and eye contact. In this way, irritation effects will be precluded.