Safer Woodworking is Rooted in Knowledge
Carpentry is one of the oldest and most enduring skills known to man. Many of the most rudimentary tools made by prehistoric people were intended for cutting and shaping wood. That’s no surprise, given wood’s abundance and versatility, as well as properties such as light weight, structural strength, and even the ability to float.
While most of today’s large structures are constructed from steel and masonry, woodworking continues to play an important role at most construction sites in everything from temporary structures and bracing to forms for concrete. Inside buildings, wood may be used for framing, flooring, doors, and decorative aspects such as wainscoting.
Because wood is so familiar to us, it’s easy to forget that working with it involves a variety of hazards. That’s why it makes sense to review the ways in which interactions with wood can lead to injuries or other health problems. The hazards associated with working with wood generally fall into two categories: those related to safety, and those related to worker health. We’ll address both groups in this article.
Essentially, safety hazards involve situations in which a worker may become injured. Several specific types of safety hazards are inherent in woodworking. The first of these is hazards related to the machines used by workers.
Point of operation. One type of machine hazard focuses on what’s known as the point of operation. That’s the physical location at which the machine performs its work. An example of the point of operation with a circular saw is the point at which the blade comes in contact with the wood. A worker who places his hand too close to the point of operation risks being cut by the saw. While that may be the most obvious hazard, it’s not the only one. Another common hazard involves situations in which the saw blade grabs the stock that is being cut and pulls the worker’s hand to the blade, or when the stock somehow becomes stuck and jams the blade.
Most machines in use today have been engineered to include some kind of guard to reduce the possibility that a worker may come in contact with the point of operation. However, if guards are removed or poorly maintained, that protection will not be available. In addition, if proper lockout-tagout procedures are not used while the machine is being cleaned or repaired, workers may come in contact with blades or similar objects.
Rotation/Reciprocation. Woodworking machines generally accomplish their tasks through either a rotating or reciprocating motion. Equipment that uses rotation, such as drill presses or lathes, can snag clothing or hair and pull a worker into the machinery or twist an arm or wrist. Protruding parts of rotating equipment may also strike workers. Reciprocating equipment offers similar hazards, except its motion is either up-and-down or back-and-forth.
Pinch points. Whenever machine parts move alongside or past one another, they create the potential for the pinch (also called in-running nip) point that may catch body parts. Pinch points can do everything from crush or mangle those parts to severing them in some cases. A common example of a pinch point is the place at which a belt goes around a pulley.
Tool projections. Some types of woodworking equipment use rotating cutting heads or inserts that include a variety of cutting surfaces. An example is a router bit, which may include several blades that are positioned at different angles. If the tool is not properly inserted or becomes damaged, it may become unbalanced at operating speeds. The resulting centrifugal forces can work the blades free from the tool body and send them flying into workers’ bodies.
Kickbacks. In some cases, a saw can grab a piece of stock and shoot it back toward the operator. This is what’s known as a kickback, and it can be caused by everything from poor-quality wood with too many knots, to blades that have become dull, to incorrectly mounted cutting surfaces. Kickbacks are more common when workers are cutting parallel to the grain than when they cut across it. A similar problem occurs when the cutting equipment sends chips or splinters flying off the stock.
Other hazards. Because wood and sawdust are flammable, the threat of fire and explosion is always present. That threat increases when a worksite also involves flammable chemicals such as varnishes, solvents, or adhesives. Wood dust is especially flammable, can travel throughout the worksite, and may accumulate on a wide variety of surfaces. Any ignition source — whether it’s a welding torch, a worker’s cigarette, a tool that sparks, or a short circuit in an extension — can trigger an explosion or fire. In addition, most of the equipment used with wood is electrical, presenting the positional for shock and electrocution.
The second category of hazards focuses on items that can have a long-term effect on the health of workers. Most of these hazards involve long-term exposures with cumulative effects, so the dangers may not be readily apparent. Some are even carcinogenic.
Wood dust. Even brief exposure to wood dust can affect a worker’s health, with eye and nasal irritation very common. While those symptoms may seem minor or harmless, continued exposure can lead to more serious problems. For example, long-term exposure to wood dust can trigger problems such as asthma and bronchitis. Dust from some species of hardwoods has been identified as a confirmed carcinogen. Continued skin exposure can lead to dermatitis and similar reactions.
Noise. Often seen as one of the most insidious hazards, noise’s effects tend to be cumulative, so they may not be noticed until it’s too late to take corrective action. Beyond the potential for loss of hearing, excess noise has been associated with stress-related conditions such as cardiovascular problems, chronic fatigue, and impaired concentration. The effects of noise depend upon both its intensity or volume and its duration. A noise source that isn’t loud enough to create damage in the short term may have a profound effect when workers are exposed to it for long periods of time.
Chemicals. People who work with wood frequently are exposed to a variety of chemicals as part of the finishing process. That may include adhesives, varnishes, and other chemicals that emit solvent vapors. Besides causing effects such as headaches and dizziness in some workers, many of those chemicals have long-term impacts on organs such as the kidneys and the bladder.
As with most workplace hazards, safety professionals will first try to address woodworking hazards through engineering or controlling work practices. Woodworking machinery is often manufactured with built-in protection such as guards. However, equipment such as guards is only effective when properly installed and maintained, so regular inspections are necessary. In addition, workers must be properly trained to gain the maximum benefit of the protection, and to understand the danger of removing or defeating the equipment. If engineering or work practice controls are impossible or impractical, workers should use appropriate personal protective equipment.
Training is also a critical element of assuring worker safety. Workers need to understand the operation of the equipment they use and any inherent hazards associated with that equipment, materials, and the jobsite itself. Training is not a one-time activity. Workers should receive regular review training, especially if safety professionals notice an increase in unsafe practices. Carefully monitoring worker activities and addressing any issues quickly will minimize the chances of those practices leading to injuries.