Safer Triggers and Training Decrease Nail Gun Injuries
Nail gun injuries decline with the use of safer triggers and
training, but safety regulations are needed for residential
carpenters, according to researchers at Duke University Medical
"Over the past three years, we have consistently found the
sequential trigger twice as safe as the more commonly used
contact trip trigger," said Hester Lipscomb, Ph.D., professor
of occupational and environmental medicine and lead author of
The sequential trigger requires that the nose piece of the
nail gun be pressed down before the trigger is pulled, while
the contact trip trigger allows the gun to fire any time the
nose and the trigger are both depressed.
"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
Nail gun injuries are more common than people realize, said
Lipscomb, whose research published in 2007 showed steady
increases in nail gun injury rates. "There are more than 35,000
visits each year in the U.S. to emergency departments for
injuries from nail guns," she said.
Most injuries involve puncture wounds or imbedded nails in
the hand or fingers, but serious and devastating injuries
involving the head, face and chest also occur, according to the
research. A number of injuries, including several fatalities,
have received attention in the national press in the last few
years surrounding the research published by Lipscomb and
The researchers studied injuries among apprentice carpenters
affiliated with the Carpenters' District Council of Greater St.
Louis and Vicinity (CDC-GSV). The findings are published in the
American Journal of Industrial Medicine.
"We found that carpenters with more training were better
equipped to handle the tool and less prone to an injury,"
Lipscomb said. "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,"
Lipscomb said. The International Staple Nail and Tool
Association sponsored a voluntary change in the standard
trigger for pneumatic tools in May 2003.
"The voluntary standard change only called for shipment of
the sequential triggers rather than their use," Lipscomb said.
"Sequential triggers are now shipped with nail guns, but the
contact trip trigger is still being shipped in the same
In 2007, half of the nailing time among carpenters continued
to be completed with the more dangerous contact trip trigger,
Lipscomb said. "This was in an area with heavy media coverage
and communication of the safety hazards."
The researchers found that switching to the sequential
trigger was more effective than training in decreasing injury
rates, and another recent study showed that switching triggers
did not affect productivity.
Lipscomb's research, published last month in Public Health
Reports, showed the differences in productivity between trigger
types were less than one percent of the building time.
"Additionally, the differences in speed were affected more by
the skill of the carpenter than the trigger being used,"
"Working towards the required use of the sequential trigger
will be important in the prevention of injuries among
Lipscomb believes the message is equally important to the
general public. "Consumers can go to their local home
improvement store and purchase the same tool carpenters are
using, but they may not have any training."
"Consumers, who are less likely to receive training in tool
use, need to be sure they ask for a tool with a sequential
trigger, and they should ask for instructions in safe use as
Other researchers involved in the study include John Dement,
Ph.D., of Duke, and James Nolan and Dennis Patterson of the