Distinction should be made between non-carbonyl<unk>  and<unk>  carbonyl, Ni(CO)4, exposures
Most commonly presents with contact dermatitis<unk>  is not antigenic but acts as a hapten by binding to larger proteins, inducing conformational changes and resulting in non-self antigen recognition (type IV delayed hypersensivity immune reaction)
Widespread allergic dermatitis (non-contact) may occur when non-carbonyl<unk>  is ingested or inhaled
Severe exposures may result in interstitial lung disease and acute tubular necrosis
Most toxic form of<unk> 
Commonly described as having a musty or sooty odor
Does not cause carbon monoxide toxicity despite the in vivo liberation of CO
Symptoms may be rapid or delayed; however, most serious toxicities occur within 2 days of exposure
Shortness of breath, headache, dizziness, and vague symptoms are generally first reported, these may progress to acute respiratory distress, myocarditis, seizures, cerebral edema, and death
Deaths typically result from interstitial pneumonitis or cerebral edema and typically occur within 2 weeks of exposure
Sequelae include a prolonged neurasthenic syndrome
Basal cell carcinoma
Other type IV delayed hypersensitivity immune reactions
Nickel toxicity
Nickel carbonyl exposures should be considered in all relevant occupational or industrial exposures presenting with significant pulmonary, cardiac, or neurological findings. Other occupational and toxicological exposures that should be considered.
Zinc toxicity
Manganese
Mercury toxicity
Cadmium
Gold toxicity
Elemental mercury