Nail gun injuries in apprentice carpenters: risk factors and control measures

Nail guns increase residential construction productivity but their use is associated with risk of injury.

Active surveillance data from 772 apprentice carpenters were used to document the injury risk associated with the use of nail guns and the potential impact of modifiable risk factors. Using reported work hours and nail gun injuries injury rates per 200,000 hr worked in the past year were calculated. Using estimates of hours of tool use, Poisson regression was used to calculate adjusted rate ratios for injury associated with time in the trade, trigger mechanism on the tools and training prior to injury.

Forty-five percent of these apprentices had sustained a nail gun injury; injury rates in the past year based on hours of work were considerably higher than previously recognized. Those with less than 1 year in the trade compared to those with more than 5 years experience (RR = 2.7; 95% CI 1.2, 5.9) and those with no training in tool use (RR = 2.9; 95% CI 1.9, 4.4) were at greatest risk. After adjusting for experience and training, the rate of injury was twice as high with tools with a contact trip trigger compared to those with a sequential trigger (RR = 2.0; 95% CI 1.2, 3.3).

Preventive measures should include change to the safer sequential trigger that prevents unintentional firing and early training in safe tool use. Because of the high prevalence of use of tools with contact trip triggers the greatest number of injuries among these apprentices could be prevented with an engineering solution.