Electrical hazards to tree workers are, for the most part, within the realm of those who access tree canopies. True, we do have electrocutions and electric-shock injuries among ground workers, but they are the minority. Tree canopies and electric supply lines often are intertwined with, or at least near, climbers and
aerial-device operators.

Class E helmets provide only a measure of protection. All photos courtesy of John Ball.

Climbers run the greatest risk, at least based on the number of incidents. The contacts are mostly indirect, either through a conductive tool or cut branch. But aerial-device operators also are at risk. Aerial-device operators sometimes become complacent while working around overhead power lines. They assume the insulated qualities of the boom and bucket will protect them from electric shock.

Trees or palms and overhead power lines are a common combination.

Aerial-device electrical incidents
An aerial-device operator working from an insulated platform attached to an insulated boom has a measure of protection against electrical shock, but not absolute protection. First, if the operator contacts the power line through a conductive tool or cut branch that is touching the tree, they have bypassed the insulation. They become the bridge for electricity – the fluctuation or flow of electrons – between the line and the tree.

Even if the operator is isolated from a ground, such as the tree, they still can be shocked. Insulation is not perfect, and it was designed for protection, not as a barrier. Our industry has too many examples of aerial-device operators electrocuted from indirect contact with an overhead power line. One fatal practice is “batting” cut branches with a pole, so the falling branch is kicked away, as sometimes the arc of the pole-saw swing intersects the power line.

The risk of electrocution is even greater when operating the many aerial devices that have no insulating properties. These are never to be operated within 10 feet of an overhead power line. We are seeing an increase in incidents from operators touching an overhead power line indirectly through a cut branch or conductive pole saw while standing in or on a metal platform.

While fewer, we do see incidents where the aerial-device operator directly touches the overhead power line. The platform and boom insulation was never designed to protect the operator from “head butting” a power line! The contact is most often across the back, shoulder or neck. Sometimes the operator was not aware of the power line; it was lost in the foliage and missed during the hazard assessment, or the assessment was not done. Other times, the operator was looking in another direction and did not realize they were closing on the line.

Aerial Lifts, Electrical Hazards and the Revised Z133 & Electrical Hazards Checklist Click Here

Ground-worker electrical incidents related to aerial devices
There has been an increase in step-and-touch potential incidents to ground workers. The source is the aerial device encountering an overhead power line. This is sometimes below the insulated portion of the boom. Once this occurs, the entire truck below the insulted boom becomes energized. Electricity is always going to seek a path to ground, so the current flows from the truck to the outriggers and dissipates though the surrounding soil and pavement.

Touch potential: If a ground worker is touching the aerial device at the same time the aerial device is touching the power line – often because they were opening a side box or even the truck door – they will become a path to ground. The voltage difference between the energized device and the ground will allow current to flow through the person. The amperage can be greater than 100 milliamps, sufficient to cause serious electrical-shock injury or even death.

The best advice is, do not touch any truck that is operating within 10 feet of overhead power lines. Pull everything you need out of any side box before the boom enters this space. Do not get in and out of the cab if the booms are operating closer than 10 feet to the overhead power lines. It might look like a good spot to take a break, but tree workers have died stepping out of the cab at the same time the boom knuckle touched the power line.

Indirect contact through a conductive pole tool is one of the most common electric-shock incidents.

If you are in the cab when the boom touches the overhead power line, stay in the cab. The metal frame acts as a large Faraday cage, which conducts the electricity on the exterior while protecting the occupants. If you must get out because of a fire, jump out and land with your feet touching each other. This is not easy to accomplish, and should only be attempted if there is a risk of burning if you remain in the cab.

The challenge is landing on your feet with both feet together. If the feet are separated when the ground is contacted, there is a risk of step potential.

Step potential: When the uninsulated boom contacts the power line, electricity will flow to the ground through the outriggers. The pads used by most tree companies for their outriggers do not provide insulation from contact with high-voltage power lines, nor do the tires. Once electricity reaches the ground, the voltage dissipates along a gradient; think of this as nested circles of diminishing voltage from the outriggers. The distance between the rings of different voltages is dependent on the resistance of the media, such as soil, concrete or asphalt.

Voltage is a difference in potential, which allows current to flow. If the two points are at the same voltage, there is no current flow. This is the reason you shuffle away from an energized truck. Keeping feet touching one another means the potential is the same, so there is no current. And shuffling means keeping the feet touching, not sliding, on the ground.

When teaching an in-person Electrical Hazard Awareness Training (EHAP) class, I will stop and ask someone to demonstrate shuffling. About 80% of the time the person slides their feet on the floor – but separated. The feet must remain together.

But how far do you shuffle away from the energized aerial-device truck? At least 30 feet, and some recommendations are 50 feet. That is quite different from the 6 feet we were taught back in the 1980s!

Conclusion
Aerial devices are an efficient and safe means for tree workers to navigate tree canopies. While the electrical-contact incidents are fewer for aerial devices than for climbers, they still occur every month in this country. Aerial-device operators should be aware of the electrical hazards to them and their ground crew related to the operation of this equipment.

John Ball, Ph.D., BCMA, CTSP, A-NREMT (Advanced-National Registry of Emergency Medical Technicians), is a professor of forestry at South Dakota State University.

Seven lift operators killed in 12 incidents in 18 months

The following accounts were pulled from TCI Magazine Accident Briefs.

Lift operator injured in electrical contact
A lift operator was seriously injured when he contacted a power line while doing tree work October 31, 2025, in Anna, Ohio. Billy Ray Kelly, 44, of Columbus, was in a boom lift trimming branches when he grabbed what he apparently thought was a support cable, but turned out to be a live power line. He suffered a severe electrical shock. Kelly’s co-worker immediately lowered the lift and called for help. Anna Fire/EMS treated him on scene before he was flown by CareFlight from Anna Park to Miami Valley Hospital in critical condition. Officials say he suffered major injuries to his right arm along with
additional exit wounds from the electrical shock, according to WDTN and www.facebook.com/homegrowntonealerts reports.

Lift operator burned contacting power line
A lift operator was badly burned while trimming trees in Minneapolis, Minnesota, August 27, 2025, after he came in contact with a power line. Fire crews responded to reports of a man with a chain saw in a bucket truck who was unconscious after coming into contact with the power line. Firefighters arrived and requested that Xcel Energy respond, because the truck was still touching live electrical wires. The truck was “not operatable,” and crews could not bring down the boom. The man was eventually hospitalized for his injuries, according to a Source Star Tribune report.

Lift operator electrocuted
A lift operator died after contacting power lines August 25, 2025, in Sterling Heights, Michigan. The 41-year-old man, a school-bus driver, was trimming trees around the bus parking lot when the incident occurred. He was transported to the hospital, where he was pronounced dead. It was unclear why he was trimming trees, according to a FOX 2 Detroit report.

One worker dies, another seriously injured from contact with power lines
One worker died and another was seriously injured when they came in contact with power lines August 14, 2025, in Salem, New Hampshire. Marc Glasser, 45, of Salem, was found dead in the bucket of the lift truck. Another worker was transported to the hospital with serious injuries, according to a WCVB report.

Man killed by electrical shock
A man was killed when he came in contact with a power line June 2, 2025, in Amboy, Illinois. Daniel Hicks, 55, of Earlville, Ill., was trimming a tree from a lift when he came in contact with the line. Hicks was alive when emergency crews arrived, but they had to wait for the power to be shut off before they were able to help him, according to a WIFR Newsroom report.

Tree worker injured by electric shock
A tree worker was injured when she was shocked February 15, 2025, in Abilene, Texas. The 22-year-old was working as part of a tree-trimming crew when the crew’s bucket-truck boom struck a power line. It was unclear if the victim was in the bucket or if she was on the ground and received a shock through the truck. She was treated in Abilene and then transported to a burn unit in Lubbock, according to a KTAB report.

Worker seriously injured by electric shock
A worker on the ground was seriously injured when he received an electric shock from an energized aerial-lift truck while clearing trees December 10, 2024, in Newport, Tennessee. Jonathan Lane was walking around the truck when he came into contact with the truck after the truck’s boom had accidentally touched the power line. Co-workers performed CPR, and Lane was transferred to a local hospital by first responders. Lane was out of danger but was expected to be off the job for six months, according to a WVLT/Gray Local Media report.

Crew leader electrocuted
A crew leader was killed while trimming trees August 3, 2024, in Battle Creek, Mich. The 50-year-old was trimming trees from a boom truck when a limb came in contact with a power line, electrocuting the worker, according to a WILX News 10 report.

Worker electrocuted
A tree worker was electrocuted June 27, 2024, in Hudson, Florida. The worker was trimming trees from a bucket truck when the bucket became energized, according to a Fox 13 News report.

Worker electrocuted while trimming near power lines
A worker died when the bucket lift he was working in touched power lines June 15, 2024, in Peru, Maine. Giles Anctil, 81, of Peru, was trimming trees when the bucket touched a power line, according to a Bangor Daily News report.

Worker receives electric shock
A worker received a major electric shock May 23, 2024, in Hunter, New York. The boom of a bucket truck made contact with a power line, which then broke. The worker, who was standing on the ground, was shocked. He was treated at the scene and later transported to a hospital, where he was expected to be discharged, according to a WNYT report.

Worker electrocuted
A worker was electrocuted while trimming a tree from the bucket of an aerial-lift truck March 18, 2024, in Stilwell, Oklahoma. Dalton Stevens, 23, of Tahlequah, Okla., was trimming a Bradford pear tree with another employee in the bucket when Stevens was killed. The power line was approximately 15 feet away, and the direct cause of the accident was not known, according to a report relayed directly to TCIA staff.

For more Accident Briefs, visit accidentbriefs.tcia.org.