About one in three workers think wearing a helmet on construction sites is unnecessary, even though most comply with the requirement, a survey has found. The three-year poll commissioned by the Occupational Safety and Health Council, a government-funded body, interviewed 92,000 construction workers. Council chairman Ng Da-lun said workers' safety awareness was low, and it was estimated economic losses caused by industrial accidents were about $145 million over three years. Although the poll found about 90 per cent wore safety helmets at working sites, 30 per cent said it was not necessary. About 20 per cent said they had suffered one to two injuries during the three-year polling period. Slippery floors accounted for 25 per cent of industrial accidents. Men had a higher chance of being involved in accidents than their female counterparts, the poll results found.