The human data unequivocally show that nickel carbonyl is an agent which is extremely toxic to man; the animal data are in agreement with respect to this acute toxicity.
It is not possible to assess the potential carcinogenicity of nickel carbonyl from either human or animal data. Unless additional, long-term carcinogenicity studies in animals can be conducted at doses that do not exceed the Maximum Tolerated Dose (MTD) for toxicity, the database for the carcinogenicity of nickel carbonyl will remain unfilled. This issue may only be of academic interest since engineering controls and close monitoring of nickel carbonyl exposure to prevent acute toxicity greatly limit possible exposures to this compound.
Exposures to nickel carbonyl are usually confounded with exposures to other nickel compounds. However, for acute nickel carbonyl exposures urinary nickel can be used as a health guidance value to predict health effects and the need for treatment. Reasonably close correlations between the clinical severity of acute poisoning and urinary concentrations of nickel during the initial three days after exposure have been established as follows:
These values, however, are only relevant when urinary nickel is not elevated due to other nickel compound exposures.
Experience at a nickel carbonyl refinery has shown that the clinical severity of the acute nickel carbonyl exposure can also be correlated to nickel levels in early urinary samples (within the first 12 hours of exposure). The use of an 8-hour post exposure urinary nickel specimen may also be helpful in categorizing cases and determining the need for chelation therapy.