Occupational asthma in the aluminum smelters of Australia and New Zealand: 1991-2006.

Objective: To examine the incidence of occupational asthma in the seven aluminum smelters of Australia and New Zealand from 1991 to 2006.

Methods: Incidence and exposure data were collected by survey from the smelters prospectively during the study period.

Results: The incidence of occupational asthma across all smelters combined was highest in 1992 at 9.