NIOSH/OSHA Release Guidance on Nail Safety

By Dr. Cathy J. Rotunda
Writer-Editor
National Institute for Occupational Safety and Health

Nail guns are popular construction tools that boost productivity. But this comes at a cost, because these power tools play a role in 37,000 injuries a year. General contractors now have a resource to help prevent nail gun injuries and to promote nail gun safety on their jobsites.

Nail Gun Safety: A Guide for Construction Contractors, now available in Spanish (Seguridad con las pistolas de clavos), was jointly prepared by the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA). Nail Gun Safety was developed at the request of OSHA’s Advisory Committee for Construction Safety and Health, which is made up of employers and labor, state, and public representatives.

Most reported nail gun accidents injure the tendons, joints, nerves, and bones of the hands and fingers. But the leg, knee, thigh, foot, and toes receive a fair share of injuries. The more serious injuries—those involving the spinal cord, head, neck, eye, internal organs, and bones—have caused paralysis, blindness, brain damage, bone fractures, and death.

How do nail gun injuries happen? Research shows seven ways a nail gun can cause injury:

1. Unintended nail discharge from double fire;
2. Unintended nail discharge from knocking the safety contact with the trigger squeezed;
3. Nail penetration through the lumber work piece;
4. Nail ricochet after striking a hard surface or metal feature;
5. Missing the work piece;
6. Awkward-position nailing; and
7. Bypassing safety mechanisms.

Nail gun safety starts with understanding nail gun trigger mechanisms. Sequential triggers are the safest type. They fire a nail only when the safety contact tip is first pushed into the work piece, followed by squeezing the trigger. Both the safety contact tip and trigger must be fully released before another nail can be fired.

Contact triggers will fire a nail when either the safety contact tip or trigger is activated first. If the trigger is kept squeezed, then a nail will be fired each time the safety contact tip is pushed into the work piece. This is often called bump firing.

Nail Gun Safety lists six practical steps that construction contractors can use to prevent nail gun injuries:

(1) Use full sequential trigger nail guns. A full sequential trigger is always the safest trigger for the job, because it reduces the risk of unintentional nail discharge and double fires.

(2) Provide training. Safety training involves much more than handing employees the manufacturer’s tool manual. To effectively reduce the risk for nail gun injuries, contractors and their employees should understand these aspects of nail gun safety:

How the nail gun (and trigger) works;
How injuries occur;
What to do when the nail gun malfunctions;
What nail gun work procedures the company requires;
What personal protective equipment (PPE) is required;
How to report an injury; and
How to give first aid.

Hands-on training should include instructions on how to load the nail gun, run the air compressor, fire the nail gun, hold lumber during placement, spot ricochet-prone situations, perform awkward position work (toe-nailing and working on ladders), manage nail gun recoil, and avoid double fires.

(3) Establish nail gun work procedures. Accidents can injure nail gun users, coworkers, and others nearby. Safe work procedures include those common to all construction tasks and those that address the particular risks of nail gun work.

(4) Provide PPE. Safety shoes, required by OSHA on residential construction sites, will help protect workers from nail gun injuries. For workers using nail guns, contractors should provide hard hats, high-impact eye protection, and hearing protection.

(5) Encourage reporting and discussion of injuries and close calls. Studies show that many nail gun injuries go unreported. Company policy should include open discussions of all nail gun injuries and close calls. These "teachable moments" help both the experienced worker and the novice, ensure workers get medical attention, identify unrecognized job site risks, and prevent injuries.

(6) Provide first aid and medical treatment. Even seemingly minor nail gun injuries can have less obvious complications, such as embedded glue/plastic/clothing that can lead to infection, secondary injury from improper removal of a nail, or undetected bone fracture. Every injury, even those that seem minor, should receive immediate medical attention.

Nail guns are powerful, loud, and heavy, causing additional risks to workers. Contractors can provide a safe worksite by following industry standards, recommendations, and strategies designed to prevent these types of injuries.

Air Pressure. OSHA’s construction standard (29 CFR 1926.302(b)) on pneumatic power tools calls for using safety devices that keep the user from accidently disconnecting the tool from the hose and require contact between the tool’s muzzle and the work surface before the tool ejects the fastener.
Noise. Pneumatic nail guns produce short, loud noise peaks from driving the nail and from exhausting the air. Peak noise levels of nail guns range from 109 to 136 dBA. This is close to 140 dBA, the level known to instantly damage the ear. NIOSH recommends that workers use earplugs or muffs to protect against a one-second burst of 130 dBA. Workers can also be injured by much lower levels of continuous noise. For instance, 15 minutes of 115 dBA has the same effect as eight hours of 90 dBA. NIOSH recommends workers wear hearing protection if they are exposed to an average of 85 dBA over an eight-hour shift.
Musculoskeletal disorders. Holding an eight-pound nail gun for a long time in awkward hand/arm positions can cause soreness or tenderness in the fingers, wrist, or forearm tendons or muscles. Such overuse can lead to pain and the inability to work. Workers who have these types of musculoskeletal disorders should immediately seek medical attention. More information on work-related musculoskeletal disorders can be found on the NIOSH website.

Nail guns help workers complete jobs faster, but the high number of nail gun injuries show that when used improperly these power tools can make workplaces less safe:
Nail gun injuries cause 37,000 emergency room visits each year.
More than half of these injuries are to the hands and fingers, where tendons, joints, nerves, and bones can be damaged.
Injuries have caused paralysis, blindness, brain damage, bone fractures, and death.
One in 10 nail gun injuries happen when coworkers are hit by projectile nails or they bump into a coworker using a nail gun.
Contact trigger nail guns pose twice the risk for injury over sequential trigger nail guns.

For copies of Nail Gun Safety: A Guide for Construction Contractors, contact NIOSH at 1-800-CDC-INFO (1-800-232-4636), or TTY at 1-888-232-6348. Ask for DHHS (NIOSH) Publication Number 2011-202. An electronic version (PDF) can be downloaded from the NIOSH Web site at www.cdc.gov/niosh/docs/2011-202/. For the Spanish version, ask for DHHS (NIOSH) Publication Number 2011-202 (SP2012) or download a copy from http://www.cdc.gov/spanish/niosh/docs/2011-202_sp/.