Preemployment medical examinations in a compressed air tunneling project in Hong Kong

One thousand workers intended to be employed in a compressed air tunneling project in Hong Kong had preemployment medical examinations for fitness to work in compressed air. Only 69.3% were declared fit and the overall unfit rate was 22.1%. The major disqualifying medical conditions were lung and heart abnormalities and chronic otitis media. Chest x-ray was found to be the most useful procedure in detecting the disqualifying conditions. The type I bends rate of the contract during the same period of examination was low: 1.39% at maximum working pressure of 2.45 kg/cm2, and there was no case of type II decompression sickness. Although many factors may affect the bends rate, it is suggested that the strict criteria adopted in the selection of workers might have contributed to the satisfactory outcome in the prevention of decompression sickness.