Skin irritation potential of copper compounds.

Data on the dermal irritation by copper and its compounds is scant, and its irritancy has not been determined, e.g., in terms of an irritant dose ID50. Irritancy of copper can only be comparatively characterized in relation to other metal salts. A rank order for the irritancy of metal compounds can be inferred from the patch test concentrations recommended as non-irritating for the purpose of cutaneous allergy testing: potassium dichromate 0.5% in petrolatum; copper sulfate, cobalt chloride and palladium chloride ex equo: 1% in aqueous solution, and nickel sulfate: 5% in petrolatum.