Death following exposure to fine particulate nickel from a metal arc process

A man was taken ill suddenly while spraying nickel using a thermal arc process. He was relieved of his duties and sent home. His condition deteriorated and he was admitted to hospital with a diagnosis of pneumonia. Thirteen days after exposure he died. At post mortem examination the cause of death was determined to be shock lung or Adult Respiratory Distress Syndrome (ARDS). Reproduction of the conditions under which the man had operated the metal arc process produced nickel concentrations of 382.1 mg m-3 in the air next to the operator. Of this nickel, 64.6% was in the form of particles less than 1.4 microns in diameter; the majority being 50 nm in diameter. The total amount of nickel inhaled by the man, who operated the process for 90 min, was estimated to be nearly 1 g. The toxicity of the nickel is thought to be associated with the very fine particulate nature of the metal fume and the large amount inhaled. The importance of wearing adequate protective equipment while operating this metal arc process is stressed.