Nail guns are powerful construction tools that are easy to operate and boost productivity but require attention and care to use safely. They’re among the most common causes of injury in residential construction, particularly in framing and sheathing work as well as roofing, exterior siding, and finishing. Accidents are especially common among new workers: the Occupational Safety and Health Administration (OSHA) found that 2 out of 5 apprentice carpenters suffered a nail gun injury during their first 4 years of training, with 1 out of 5 injured twice and 1 out of 10 injured more than twice.

Nail Gun Action Mechanisms

Understanding different nail gun mechanisms is crucial to using them safely. There are two basic mechanisms, a finger trigger and a contact safety tip located on the nose of the gun. Nail guns require both mechanisms to work and the gun’s action depends on what order they are activated and whether the action is easily repeatable.

1. Full Sequential Trigger: A single-shot trigger in which the safety tip must be pushed into the work piece, after which the finger trigger must be squeezed. This full process must be followed for each nail.
2. Contact Trigger: A multi-shot trigger that can be activated in any order. If the trigger is kept squeezed, it will fire a nail each time the safety tip is pushed into the work piece.
3. Single Sequential Trigger: Operates similarly to the Full Sequential Trigger, where the only difference is that the trigger may be pulled multiple times as long as the safety tip remains pushed into the work piece.
4. Single Actuation Trigger: Can be activated in any order. If the safety tip is kept pressed, it will fire a nail each time the trigger is squeezed.

Common Causes of Nail Gun Injuries

Different trigger mechanisms are susceptible to different errors.

1. Unintended double fire: Most common with Contact Triggers when the trigger is kept squeezed and the user is trying to accurately place the nail gun against the work piece, causing an expected second firing.
2. Unintended discharge from knocking the safety contact with the trigger squeezed: This happens with Contact and Single Actuation Triggers, when the trigger remains squeezed while the safety contact tip accidentally gets knocked or pulled into an object or person.
3.  Nail penetration through lumber: This can happen with any trigger type and occurs when the nail breaks through a weak spot such in a piece of lumber, often near a knot.
4. Nail ricochet: This can happen with any trigger type and occurs when the nail strikes a hard surface or metal feature, such as a knot in lumber or metal framing hardware, and bounces off, becoming a projectile.
5. Missing the work piece: Incomplete or missed contact with the work piece can happen with any trigger type and most often happens when nailing near the edge of a work piece.
6. Awkward position nailing: Attempting to nail in awkward positions where the tool or recoil is hard to control can lead to injury. This includes nailing in tight quarters, while on a ladder, over a leading edge, above the shoulder, or toe-nailing. Whenever a nail gun is used beyond a comfortable reach distance, with a non-dominant hand, or when the user’s body is in the line of fire, an injury can occur.

Nail Gun Safety Tips

       1. Regularly check equipment functionality and condition

       2. Ensure that manufacturers’ tool manuals are always available for employees and followed completely

       3. Use the Full Sequential Trigger wherever possible. This is the safest trigger mechanism

       4. Never bypass or disable nail gun safety features

       5. Set up proper working conditions

              a. Ensure that surfaces are clear of potential dangers like lumber knots, nails, straps, and hangers

              b. Keep workers are out of the line of fire

              c. Assure that a nailer can be used comfortably within reach with your dominant hand

              d. Keep your hands at least 12 inches away from the nailing point at all times

              e. Use a nailer below head or face height

              f. Take exceptional care and extra time to prepare a safe environment when working at height, toe-nailing, or working in tight quarters

              g. If you cannot meet these conditions, use a hammer instead

       6. Disconnect the compressed air when leaving a nail gun unattended, passing it to someone, moving into a new position with it, or performing any maintenance on it

       7. Use proper PPE including hard hats, ANSI Z87.1 safety glasses and goggles, and hearing protection

       8. Report all nail gun incidents and ensure that medical attention is sought immediately after injury