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6 Shocking Underwater Welding Dangers & Powerful Safety Solutions

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Safety first.

And last.

If you’ve ever worked under a diving adviser or taken a welding class, safety is the primary emphasis. Because underwater welding dangers are prevalent, safety is of equally high importance. A little common sense and understanding of diving operations make all the difference.

Underwater welding is not the most dangerous job in the world. Not by a long shot. But just how dangerous is underwater welding?

We’re steering away from the rumors and looking at the facts.


Most diving classes and employers use safety manuals to explain these safety issues. I’m only including the essentials:

  • Major threats posed to underwater welders
  • Safety tips to combat each threat

Keep in mind:

  • As a welder-diver, you are adopting not only the benefits but the risks of two professions. Also, risk can equate with underwater welding income.
  • Most of the underwater welding dangers below pertain more to wet welding than dry welding, but all have an application to divers.

Underwater Welding Dangers: Diving Equipment & Body

Electric Shock Dangers

Water poses little resistance to electricity, and if left ungrounded electric current will flow freely through water like a hot knife through butter.

All welder-divers face risk of electric shock, especially during wet welding since their entire atmosphere is composed of water. Welder-divers that work in “splash zones” (areas intermittently covered by water) face even more risk given the exact position they must hold while they work – water waves can throw them off-balance and cause variables loosen their grounding cable. Three independent actions occur simultaneously to shock diver-welders:

  • Part of their operating equipment experiences electrical failure
  • Ground fault interrupter fails
  • Underwater welder goes between path of fault and earth ground

Note: There is only one recorded incident of an underwater welder dying while wet welding. Though the job is risky, many of the beliefs of underwater welding dangers and lethal power are unfounded. Studies have shown that drowning and decompression sickness are the primary killers of underwater welders.

Electric Shock Safety Measures

Most preparation for underwater welder projects happens above, not below water. Proper equipment inspections are crucial to reducing risk of shock. Direct current (DC), not alternating current (AC), should be used to power welding equipment.


  • Wear rubber suit and gloves.
  • Glove gauntlets should firmly attach to wrists so no slag floats in.


  • Watertight and completely insulated. To insulate exposed parts, apply rubber tape, scotch cote then electrical tape.
  • Strain relief must be incorporated in cables at deeper water levels.


  • Use waterproofed electrodes that are fully insulated.
  • When electrode is powered or “live:” Never carry electrode around with you (if you’re already carrying it, don’t put it down suddenly – this may ground the charge through your body). Never change out the electrode.
  • Handle loose metallic items carefully so they don’t come in contact with electrode.

Safety (Knife) Switch

  • Open only right before diver-welder is ready to power electrode.
  • Always use double-pole switches – they possess working and ground lead that close simultaneously to interrupt current.

Power Supply

Underwater Explosions


Underwater welding produces gases (oxygen, hydrogen) that have explosive potential if combined in high levels. During wet welding, welder divers may hear a small popping sound caused from hydrogen and oxygen bubbles traveling upward and collecting. This sound should serve as a warning to stop underwater welding immediately to locate the area where gas is collecting.

Explosion Safety Rules

  • Look for any parts of work area that could trap gases overhead. If needed, use a vent tube to direct gases to the surface.
  • Weld from the highest to lowest point if possible.
  • Electrodes that exceed 10,000 degrees Fahrenheit in a gaseous environment may explode if a spark occurs.
  • Thick material: Work from outside and around circumference. Pull away the electrode every few seconds and make brush action. You may want to allow water to enter weld to keep the temperature down, though this reduces its quality.
  • If working on or above river beds, remember that mud may already have explosive methane gas trapped within it. And a river bed with cows nearby? Forget about it.

Health Risks

Diver Bends (Decompression Sickness)


Because many welder-divers work hundreds of feet underwater, they undergo pressure changes that can cause harmful effects on their body on their way up.

Decompression sickness or “the bends” happens when welder-divers make their journey to the surface too quickly and pushes dissolved gases into other parts of the body too quickly and pushes dissolved gases into other parts of the body through the bloodstream. Similar to putting your foot on a half-full balloon and creating bulges in odd places. Symptoms of the bends include dull pain, itching and fatigue in these parts of the body:

  • skin
  • lungs
  • ears
  • brain
  • joints
  • spinal cord

Diver Bends Safety Measures

To transport welder-divers to deep levels underwater, they use a pressurized cabin known as a “diving bell.” This bell will maintain appropriate pressure levels to help diver-welders’ bodies adjust. From the bell, diver-welders will work in either the water or a hyperbaric chamber. To decrease risk of decompression sickness coming up to the surface, diver-welders should avoid the following:

  • Ascending quickly after a deep dive
  • Continuous underwater dives in a few hours’ span
  • Flying quickly after diving
  • Becoming dehydrated
  • Drinking alcohol

In general, underwater welders only ascend about 33 feet per minute with proper decompression. Companies employing diver-welders follow rigorous guidelines for decompression using computers that calculate decompression rates for all their equipment, but diver-welders must still be aware of these procedures in case equipment malfunctions.

In addition to decompression sickness, all divers expose themselves to various risks underwater. Although not as high profile in nature, hyperbaric welders should prepare themselves for these risks:


Malfunctions in breathing equipment such as your mask, hoses or oxygen tank(s) are one of the most daunting underwater welding hazards, especially in situations where they cannot come to the surface quickly. Because underwater welders use surface supplied oxygen, their umbilicals can twist and rip. These dangers are amplified during projects with high water current, demolition and salvaging.

Drowning Safety Techniques

Above all, don’t panic. Divers can make a dangerous situation lethal by overthinking and not following the surface team’s direction. Keep a calm head and slow your breathing as much as possible. If your air supply is cut off through the umbilicals, you may switch to your emergency SCUBA supply tank. Check your helmet for malfunctions. If you’re far below the surface, ascend at a safe rate.


As a rule of thumb, the deeper the descent, the colder it gets. If water penetrates your skin, your body temperature will quickly drop in a cold environment. This can lead to respiratory problems, hypothermia and death.

Safety Measures for Freezing Hazards

In addition to highly insulated scuba equipment, welder-divers should check for any small tears in their dry suit and gloves.

In certain cases, saturation divers will use helium in their environment to reduce chances of decompression sickness. Because of helium’s thermal properties, divers must constantly monitor their temperature after absorbing large amounts of helium into their bloodstream. Hypothermia can onset in a matter of minutes.

Marine Life


Cue Jaws music – not really. However, light from welding can attract plankton, and plankton attract fish. Though marine life are not a major case of underwater welding injuries, they can get in the way of the welder-diver’s work and cause delays. Increased project time means increased risk.

Marine Life Safety Measures

Underwater welders should explore their work area beforehand to clear away any obstacles, including fish.

Hyperbaric Welding Dangers & Risks: Educating for the Future

As you can see, there’s a multitude of operations and procedures in every maritime project involved with underwater welding.

It is my hope to provide the most fundamental risks so as to educate individuals interested in pursuing an underwater welding career. Veteran hyperbaric welders may need a “refresher” as well.

Because underwater welding is only decades old, the long-term effects and dangers are unknown. Researchers continue to study the health and safety of welder-divers as they age. Their results will give us new information to apply.

Until then, we must go into the profession with the wonder and respect that it deserves.

Cameron Dekker

Cameron grew up in Allentown, Pennsylvania, a once-proud steel town on the Lehigh River, where he got a taste of TIG welding in his high school shop class. He holds certificates for Certified WeldingEducator (CWE) and Certified Resistance Welding Technician (CRWT) from the American Welding Institute. His interests include scuba diving, sculpture, and kayaking.