OBJECTIVES--To investigate the respiratory health of dock workers who load grain cargoes. METHODS--The respiratory health of 118 dock workers who load grain cargoes in the ports of Vancouver and Prince Rupert was compared with that of 555 grain elevator workers from the same regions. 128 civic workers were used as an unexposed control group. RESULTS--The prevalences of chronic cough and phlegm were at least as high in dock workers as those found in the elevator workers, and when adjusted for differences in duration of employment and smoking, dock workers had an eightfold higher risk of developing chronic phlegm than did civic workers. Symptoms of eye and skin irritation that were experienced at least monthly were highest for dock workers. Average percentage of the predicted FEV1 and FVC for dock workers (mean 100.6% and 105.3% respectively) were similar to the civic workers but significantly higher than those found for elevator workers. Higher subjective estimates of duration of exposure to grain dust (hours/day) were associated with lower values of FEV1. CONCLUSIONS--The more intermittent grain dust exposure patterns of dock workers may have allowed for some recovery of lung function, but chronic respiratory symptoms were less labile.