THURSDAY, Aug. 14 (HealthDay News) -- Safer triggers and training have helped reduce nail gun injuries, but safety regulations are needed to help protect residential carpenters, say Duke University Medical Center researchers.

Nail guns cause more injuries than people realize, according to study lead author Hester Lipscomb, a professor of occupational and environmental medicine.

"There are more than 35,000 visits each year in the U.S. to emergency departments for injuries from nail guns," she said in a Duke news release.

"Over the past three years, we have consistently found the sequential trigger twice as safe as the more commonly used contact trip trigger," she said.

The contact trip trigger allows the nail gun to fire any time the nose and trigger are both depressed, while the sequential trigger requires the nose piece to be pressed down before the trigger is pulled.

"The contact trip trigger allows workers to rapidly fire the tool and more frequently results in injuries from accidental discharges, double fires and ricocheting nails," Lipscomb said.

In this new study, she and her colleagues analyzed injuries among apprentice carpenters in St. Louis and the surrounding area.

"We found that carpenters with more training were better equipped to handle the tool and less prone to injury. Carpenters were best protected when they received both classroom training and hands-on instruction. Unfortunately, most residential carpenters, including immigrant workers, are less likely to get training compared to the union workers we studied," Lipscomb said.

"There are currently no regulations that require the sequential trigger be used or that define minimal training requirements, even though data suggests there should be," she noted.

The study was published in the American Journal of Industrial Medicine.

More information

The Canadian Centre for Occupational Health and Safety has more about nail guns.