Chain saws are among the most basic tools for tree workers. While we once performed pruning and felling with one- and two-person crosscut saws, no one would want to return to those days. The chain saw is also the power tool we most share in common with homeowners. Most people do not own an aerial lift or chipper, but many have a chain saw in the garage (yes, they rent chippers and lifts, but these are stories for future articles).
Unfortunately, any saw chain that can plane through wood fibers also can tear through flesh. Chain saws can easily slice through skin and do so at an alarming rate when operated improperly. The key phrase here is operated improperly. The modern chain saw is so light and well balanced that too many think they can wield it like a lightsaber (see Star Wars movies).
The lightsaber thing did not go well for Luke Skywalker. He lost his hand in a lightsaber fight with Darth Vader. Real fights with chain saws sometimes happen. Tree workers have fought each other with top-handled saws, bosses have held disgruntled ex-employees at bay with chain saws and members of the public even have used them in bar fights.
But none of these incidents can be considered within the realm of tree work. They are highlighted only to point out just how light our chain saws have become. No one would consider trying to fight with a 1949 McCulloch 3-25. That “lightweight” chain saw with a 24-inch bar was “only” 25 pounds, a poor choice for a weapon.
Fortunately, chain-saw massacres are mostly in the imagination of movie and television-show producers. Just as well. There are enough injuries with the normal applications of chain saws, i.e., cutting wood. We are far more likely to become the unintended target from an improperly handled saw than the intended target of Leatherface (see The Texas Chainsaw Massacre).
If you read any articles on chain-saw injuries, they frequently show figures that use injury data from a 1994 U.S. Consumer Product Safety Commission report. This data shows that about 42% of the injuries occur to the arms and hands, 38% to the legs, 8% to the head, 7% to the feet and 5% to the upper-body area, the shoulder and neck.
I have not been able to find the original source for the figures in this report, though they are cited in numerous articles. But the figures are more than 25 years old, so they may be outdated – our chain saws and PPE have changed – and the figures really do not help us separate what might be happening to tree workers operating chain saws every day versus the occasional users, i.e., the weekend woods warriors.
So, for this article, it might be interesting to look at what chain-saw injuries have happened in the past decade, 2010 through 2019, and separate homeowners from tree workers. This review covers emergency-department visits resulting from chain-saw incidents. The primary focus is on injuries that resulted in admission to the hospital rather than being treated and released; however, it also will touch upon the latter.
“Tree worker” as used in this context refers to a paid worker operating a chain saw during tree pruning or removal, excluding logging, firefighting or construction. If you were logging, you are not counted here. If you were cutting wood debris on a construction site, you are not counted here. If you were a landscaper operating a chain saw to cut wood posts on the job, you are not counted as a tree worker. If you were working as a landscaper and operating a chain saw to remove a tree, you are counted here as a tree worker. Obviously, anyone working on trees for a tree service is counted here as well.
The layperson operating a chain saw will be referred to as a “homeowner,” as home is the site for most of their injuries (after all, anyone can do tree work, and they will save money by not hiring you, right?). Some of their injuries happened while operating chain saws on other properties, such as during a church or school clean-up project, where it seems everyone with a chain saw wants to come out and do the cutting. However, once again the only homeowner injuries counted here are those that happened during tree pruning or removal, not during volunteer construction projects, such as on playgrounds, where chain saws may be used to cut posts.
The injury data comes from various databases, with the U.S. Bureau of Labor Statistics, U.S. Occupational Safety and Health Administration and hospital emergency-department visits being the principal sources. This review does not include first-aid treatments made on site for chain-saw lacerations or visits to stand-alone, urgent-care facilities. These facilities are prepared to treat minor injuries, not serious trauma associated with severe chain-saw cuts. However, some chain-saw operators with minor cuts may have used these facilities, and these visits are missing from the data sets.
How many chain-saw injuries occurred during the past decade?
There were an estimated 282,000 hospital emergency-department visits for chain-saw injuries in the U.S. from 2010 through 2019. This comes to about 28,000 a year. Only about 6% of these visits, an estimated 16,700, required admission to the hospital. Very few died in an ambulance on the way to the hospital or in the emergency department.
This does not mean chain saws were not involved in fatal incidents. They were, but fewer than 30 a year, so fatalities are relatively rare events compared to the nonfatal injuries. But nonfatal does not mean nonserious. No one would want to endure the pain from a deep laceration and the possible scarring afterwards. There is also the possibility of permanent nerve loss from lacerations. Loss of fingers and hands and limb amputations are also possible outcomes of tangling with a chain saw.
Chain-saw lacerations, the most common injury, are often jagged and deep. These wounds can become contaminated with wood dust, wood chips and other organic debris as well as metal. Severed muscles and tendons are at risk for infection, particularly near or at joints. Antibiotics, sometimes delivered as an IV along with pain medication, are used to reduce infection in these deep wounds. Treatments for chain-saw lacerations are not always simply “clean and apply a dressing.”
Injuries treated in the emergency department without admission
Homeowner chain-saw-related injuries treated in the emergency department without admission to the hospital totaled about 265,000 during the past decade. The chain saw was not the source of the injury for all these visits. A source is the object or exposure that directly produces the injury. For example, there were fractures from falls while cutting with a chain saw from a ladder, and these were coded as chain-saw incidents. The ladder pulling away from the tree and falling was the source – the chain saw was the secondary source; it contributed to the injury by throwing off the balance of the operator.
We will focus on the chain-saw-related visits to emergency departments where the chain saw was the primary source of the injury. About 209,000 of these visits, where the patient was treated and released, were trauma emergencies involving being cut by the chain of the saw. These chain-saw lacerations were mostly to the hands and fingers (33%), followed by the knee (20%) and lower legs (14%).
The average age of the patient suffering a laceration was 45.2 years old, with a range from 12 to 79. The 12-year-old was holding a branch while his father cut it with the chain saw and the saw slipped, cutting the pre-teen’s hand. The 79-year-old was struck in the knee when the saw kicked back while he was felling a tree.
It is not possible to trace most of the minor injuries as to whether they occurred to homeowners or tree workers. But we know what they were doing. Most of the time the saw was being used to fell a tree or cut a stump down, two activities accounting for most of the lower-extremity lacerations. Bucking and limbing accounted for many of the upper-extremity lacerations, along with trimming overhead branches from the ground or a ladder. A few injuries were to a thumb that was cut when the chain came off the bar.
About 1% of the injuries were finger and thumb partial or complete amputations. These can sometimes be treated in the emergency department and the patient released the same day. The amputations of fingers and thumbs usually happened while bucking and limbing fallen trees.
There were also burns that were treated in the emergency department, with the patient released that same day. These were less than 1% of the chain-saw injuries treated in the emergency department. Most burns were to a hand or finger that touched a hot muffler. They were usually superficial burns, but a few were more severe, either a
partial-thickness burn (second-degree) or a full-thickness burn (third-degree) to the finger from contact with a hot muffler. There were also a few thermal burns to arms or legs caused by ignition of leaking saw gas.
Finally, there were some other medical emergencies associated with operating a chain saw. The most common were chest pains. Just as shoveling heavy snow can trigger a heart attack, so can operating a chain saw and clearing brush. Not too surprising, the average age of patients coming to the emergency department with chest pains was 62 years old.
Injuries requiring hospitalization
About 16,700 chain-saw-related incidents during the past decade were injuries severe enough for admission to the hospital. But only about half were due to lacerations. There were also fractures, which amounted to about a quarter of all the hospitalizations related to chain-saw operations. The saw did not cause the majority of these fractures. They were due to either the tree falling on the chain-saw operator or the chain-saw operator falling from the tree. There were also burns and amputations, among other injuries.
The average age of the homeowner patient admitted to the hospital from chain-saw lacerations was 47 years old. The youngest was 9, the oldest 84. The 9-year-old fell on the chain of a chain saw that was not running. The 84-year-old set a chain saw on the ground while the chain was still spinning, and it kicked back.
The average age of the tree workers admitted to the hospital for chain-saw lacerations was 34 years old, more than a decade younger than the homeowner. The range in ages was not as wide either, with the youngest being 17 and the oldest 63. The 17-year-old lacerated his knee when the chain saw kicked back while making a back-cut. The 63-year-old cut his lower-left arm when the chain saw slipped while he was limbing.
The most common reason for admission to the hospital for homeowners operating chain saws was laceration to the lower arm, distal to the elbow. This was also the body region with the most injuries to tree workers, and for both groups it was usually the left arm, finger or hand. It seems many chain-saw operators want to hold onto the branch with one hand while operating the chain saw with the other. Another common one-handed operation was felling small trees with one hand on the chain saw during the back-cut and the other hand, usually the left, pushing over the tree. The operator loses their balance, and the left arm or hand is struck by the chain.
The hand injuries were not always to the chain-saw operator. Homeowners operating chain saws cut helpers who were holding branches for them. These incidents also happened to tree workers. There were groundworkers who were injured while darting into a falling tree to grab brush as a chain-saw operator bucked and limbed it. The chain-saw operator cut the groundworker’s hand as they reached in to grab brush. Surprisingly, some injuries were to groundworkers who were holding a branch while the chain-saw operator cut it. We should know better.
Homeowners had about the same percentage of leg lacerations requiring hospitalization as arm injuries, while for tree workers there was a higher percentage of arm lacerations than leg injuries. The most likely reason is the common use (though not universal) of leg protection among tree workers (much rarer with homeowners). While not every narrative entry provides information on the use of personal protective equipment (PPE), many narratives for leg lacerations for both homeowners and tree workers mentioned the operator was not wearing leg protection.
The narratives for leg injuries usually included the word “kickback,” and the injuries frequently happened while felling the tree. However, some leg injuries were to homeowners standing on ladders while trimming branches. The chain saw “slipped” after the branch was cut and dropped down, cutting the leg. Some tree-worker leg lacerations were for a similar reason, but to a climber supported by a climbing line rather than standing on a ladder.
Amputations were another reason for hospitalization. The majority were severed fingers and thumbs, again mostly on the left hand. Some right-finger amputations were to groundworkers holding a branch while the chain-saw operator cut it. There were also a small number of amputations to the hands or feet of chain-saw operators.
There were also burns and fractures resulting in hospitalizations. Burns from touching a hot muffler were usually the ones treated and the patient released the same day. The more severe burns, in terms of the area of the skin affected, were from fires. There were extensive – often most of a leg – full-thickness burns from leaking saw fuel bursting into flames and catching the operator’s clothes on fire.
Misuse of a chain saw sometimes resulted in fractures. Broken – maybe shattered is a better description – fingers were outcomes of having the left hand get in front of the saw. There were also mandibular fractures from kickback striking the face and mouth region. You might not think maintaining an airway would be a concern with chain-saw cuts, but this can be a challenge with lacerations to the face and mouth. These injuries occurred to both homeowners and tree workers.
There is a subset of tree workers who do not wear the same PPE as groundworkers operating a chain saw. These are climbers and aerial-lift operators. Aerial-lift operators have a bucket for protection, and for climbers, at least in the U.S. and Canada, leg protection is not a requirement. Most of the aerial chain-saw injuries (excluding homeowners on ladders) were to climbers. If we separate the tree workers into two subgroups, groundworkers and aerial workers, there were some differences in body regions where the chain-saw injuries occurred.
The most common injury for tree workers aloft, either as a climber or an aerial-lift operator, was to the lower arm, followed by the hand (which includes fingers). These were generally to the left hand. They were often incidents where the climber was operating the chain saw with the right hand and supporting the trunk piece or branch being cut with the left hand. Sometimes the hands were reversed, holding the saw handle with the left and supporting the branch with the right, but with the same outcome. The saw “slipped,” and the free hand was cut. There were also instances where one hand was operating the chain saw while the other was reaching out to a limb for balance or to catch a cut branch falling in an unintended direction.
There were fewer leg lacerations than arm and hand lacerations to the aerial tree workers. Aerial-lift operators have the bucket for leg protection, so there were no leg lacerations noted, but even climbers had fewer leg injuries proportional to upper-body injuries. While most of the leg lacerations happened from chain saws swinging down and striking the leg after the branch was cut, there was another type of incident repeatedly appearing in narratives. These were deep lacerations to the back of the lower leg when a climber attached an idling chain saw to the saddle and then continued to climb; while pulling over limbs, twigs caught the throttle, revving up the saw and sending it into the leg.
Aerial chain-saw operators had very few shoulder, neck or head injuries, despite operating saws in an environment where many might be reaching up to cut a branch. The reason? These were fatalities. Deep lacerations to the neck and face can kill – quickly.
Despite the capability of the chain saw to cut through wood with speed and power – and there are millions of chain saws used in this country – we have relatively few deaths. Even one is too many, and zero is a worthy goal, but we should also remember the thousands of severe, nonfatal injuries that occur each year due to the improper use of chain saws and the absence of PPE.
John Ball, Ph.D., BCMA, CTSP, A-NREMT (Advanced – National Registry of Emergency Medical Technicians), is professor of forestry at South Dakota State University and a Board Certified Master Arborist.