Why Is Underwater Welding So Dangerous? 

Why Is Underwater Welding So Dangerous? 

Although there are no current figures for underwater welder fatalities, it is generally accepted that underwater welding has a 15% mortality rate making it substantially higher than other occupations. If you are considering underwater welding as a career, you might be wondering why is underwater welding so dangerous for a job?

Underwater welding is dangerous due to the potential of explosions, electrocution, drowning, delta P hazards, and the bends. Underwater welders are exposed to the dangers of diving and welding combined, and the field has a high fatality rate. Environmental factors such as low visibility and environmental risks also make this job hazardous. 

There is no doubt that diving and welding are both occupations that carry potential hazards, and a combination of the two poses increases risks. However, underwater welders are in high demand, and the top-end salaries are extremely high. If you are enticed by the lure of the underwater welding life, please read on to find out why it may be dangerous.

Is Underwater Welding the Most Dangerous Job?

The Occupational Safety and Health Administration (OSHA) reported 116 commercial fatalities between 1989-1997 at 13 deaths per year, making underwater welding high on the scale of the occupational hazards, but not the most dangerous one. Logging and fishing-related deaths to the charts according to the ISHN. (Industrial Safety & Hygiene News.)

Unfortunately, many of the underwater fatality statistics are outdated, and providers fail to name underwater welding as its owns designated field specifically. However, one can deduce the risks by looking at welding and construction and the dangers of diving and correlate the two figures.

Structural iron and steel workers had 14 reported deaths in 2017 and a fatal injury rate of 28 per 100,000 workers according to ISHN and include welders in their demographic. Correspondingly, Divers Alert Network (DAN) reported  228 deaths involving underwater diving were reported in 2017 alone.

So the nature of diving is hazardous in isolation and becomes enhanced by the electrical nature of an underwater welder’s occupation.

What is Underwater Welding?

Underwater welding, otherwise known as hyperbaric welding, creates welds at elevated pressures, often underwater. Hyperbaric welding can take the form of wet welding in the water or dry welding in a specially engineered chamber underwater that maintains positive pressure.

Typically dry welding is referred to as hyperbaric and wet welding is known as underwater welding. Underwater welding applications are diverse, from ship repair to oil platforms to dams, locks, and pipelines. Underwater welders typically perform their welds on steel.

Underwater welding is generally carried out at shallower depths in a region called the splash zone, which is intermittently covered in water. However, the most challenging wet welding procedures are deeper welding underwater, a highly sought after in marine maintenance and repair.

Underwater welding is invaluable for emergency repairs at sea and in repairs to underwater pipelines. The job requires a high degree of skill and requires a high level of diving experience combined and is considered one of the world’s most dangerous occupations.

How Does Underwater Welding Work?

Underwater welders usually employ varied arc welding forms and use 300-400 amps to power their electrodes and are exposed to the water and surrounding elements. Shielded metal arc welding is typically combined with waterproof electrodes or flux-cored welding, and friction welding is used in underwater welds.

The welding power supply is connected to the welding equipment through cables and hoses and is generally used on low-carbon steels due to hydrogen-induced cracking challenges. The wet welding process is similar to the dry, but the electrode holders are made specifically for water cooling and have greater insulation.

As the electric arc heats the metal workpiece and rod, the molten metal is transferred through the arc’s gas bubble. The bubble is formed by the specialized flux coating on the electrode, and slag deposition helps slow the cooling rate.

 Is Underwater Welding Dangerous?

The life of an underwater welder is one that is fraught with a multitude of perils. Not for the faint-hearted, the job requires not only a high level of skill but nerves of steel, it seems. Welding itself can be a dangerous profession and combined with the dangers of diving, the possibility of injury and death become compounded. The most common causes of underwater fatalities are as follows.

Explosion Fatalities

Hydrogen explosions caused seven percent of reported underwater welding fatalities between 2014 and 2015. Every water molecule is made up of two parts hydrogen and one part oxygen. Cutting steel underwater increases welding temperatures to 10,000℉ and above, causing the hydrogen and oxygen to separate in the water nearest the rod’s end.

The electrical current to light the rods also causes the atoms to further separate in the water molecules. Thus underwater cutting has a doubled effect on the source of hydrogen.

Hydrogen is high explosive and unstable, and only one cubic foot of hydrogen has the same explosive force as a stick of dynamite.

Coupled with water density and the possibility of shock waves, even a relatively minor explosion has enough force to cause diver fatalities. Because underwater welders often work in irregular spaces, the accumulated hydrogen may pocket in ceratin overhanging structures and form an even greater risk.


Water itself is not a great conductor of electricity, but it contains ions of dissolved salts and metals that effectively conduct electric current. Working surrounded by a body of water places underwater welders in a precarious position, especially when using electrical equipment.

Wet welders face the risk of an electric shock, especially in unstable environments such as splash zones where waves may throw them off balance or loosen their grounding cables. Three factors that are responsible for causing electric shock in welders are:

  • Failure in the welder’s electrical equipment
  • Faults and interruptions in the grounding cable
  • The diver positions himself between the fault and the earth ground.

The Bends

Generalized barotrauma is commonly known as the bends and refers to damage caused by a rapid decrease in the pressure surrounding a diver in either the air or water. Divers take in extra oxygen and nitrogen, where the nitrogen remains dissolved in the blood. As the diver swims back to the surface, the surrounding water pressure decreases.

If this happens too fast, the nitrogen separates from the diver’s blood and forms dangerous bubbles in the tissue and blood. These nitrogen bubbles cause decompression sickness.

To use an example, opening a fizzy cooldrink causes a change of pressure. This change in pressure causes the gas to form bubbles, much like the effects of the bends. Nitrogen bubbles can damage blood vessels and inhibit normal blood flow and lead to death in severe cases. Each person reacts differently to decompression sickness, and the effects may range from barely noticeable to rapid fatalities.

Symptoms of decompression sickness are:

  • Dizziness or vertigo
  • Head pain
  • Pain in the joints
  • Excessive fatigue
  • Difficulty thinking clearly
  • Numbness and tingling
  • Weakness in the extremities
  • Skin rashes.

Modern decompression techniques and monitoring equipment have made the bends less common today. Treatment is usually hyperbaric oxygen therapy in a recompression chamber and has a high recovery rate if treated early.


An unstable environment such as the ocean has a host of complications that might cause metal welders to drown. Scuba equipment failures such as disruptions of the oxygen hose or mask failures present particular hazards to underwater welders who cannot return quickly to the surface.

Even if the diver has experience and proper equipment, drowning may occur. Underwater divers work in low viability, which drops further as they go deeper underwater. They may become entangled or pinned by their equipment in these unforgiving conditions and may not be able to free themselves in time.

A scientific study was conducted on 947 diving accidents between 1992 and 2003. The study found that of the 70 victims who drowned, their deaths were linked to injury, equipment, air-supply issues, and cardiac arrests.

Differential pressure

Differential pressure hazards are high on the list for underwater welder fatalities. Dangers of differential pressure account for 7 percent of reported diving deaths and are caused when water moves from a high-pressure area to an area of lower pressure.

Differential pressure is challenging to detect, and by the time a welder notices it, it is too late to escape. When two bodies of water at different pressure intersect, the pressure difference can rapidly create a force of hundreds of pounds per square inch. This rapid and crushing force may trap and drown an unsuspecting diver.

Differential pressure accidents can be caused by opening a valve, cutting into an empty space, or engaging a pump. The height differences between two bodies of water at different pressures generate a suction force through holes in the barrier between them. The greater the height or pressure difference, the larger and more deadly the potential suction force.


Fatalities may even occur at depths as low as 3 meters or less by the substantial suction forces present in large openings, even when there is a slight difference in water levels. Differential pressure hazards or Delta P hazards are usually identified before welding and should have the proper lockout/tag procedures in place or double isolation to protect from injuries.

Environmental Hazards

Underwater welding exposes welders to various welding environments, including lakes, rivers, dams, and oceans. Each environment contains unique challenges and potential dangers to the unwary diver. In a critical study, 36% of all driving fatalities, difficult water conditions were implicated. 

These factors involved:

  • Strong currents
  • Rough water conditions
  • Surges in a wave movement
  • Poor visibility caused by water conditions.

Underwater welders operate in some of the most extreme depths imaginable, down to 2,500 m (8,200 ft.) These unnatural operating depths may expose divers to a host of potential complications such as:

  • Impaired judgment
  • Reduced visibility
  • Increased air consumption
  • Nitrogen narcosis
  • Slower buoyancy compensator response
  • Decompression sickness
  • Hypothermia.

There is also the threat inherent in marine life such as sharks and deadly stingrays for an underwater welder to fear. Coupled with poor visibility, welders might snag scuba equipment on underwater hazards.


Deep commercial diving and long water times, welders often suffer from exposure to the cold, especially when breathing oxygen and helium mixtures. For deeper dives, the heat loss from the lungs to the colder breathing gas can be so significant that hot water suits and insulated helmets cannot provide sufficient heat to prevent hypothermia.

If adequate gas heating is not applied, pulmonary complications may occur, and the diver may succumb to hypothermia. Reduced body core temperatures below 35.0 °C (95.0 °F) in humans cause specific physiological symptoms that range in severity.

Moderate hypothermia can cause confusion and decreased reflexes, and loss of fine motor skills, while severe hypothermia compromises the heart, respiration ability, and blood pressure.

Factors that contribute to immersion hypothermia include:

  • Inadequate insulation
  • Diving in a cold, wet diving suit
  • Insufficient warm-up time between dives
  • Poor physical condition.

If it is So Dangerous, Why Choose Underwater Welding?

Not only do you travel the globe and visit remote sites, but underwater welders are also generally paid handsomely for the inherent hazards of their work. Top earners in the field can earn around $118,000 per year or more, comparable to lawyers’ and doctors’ average wages.

Underwater welders may achieve certification in under a year, whereas doctors have to spend up to seven years before they may start earning. So is a highly paid occupation that does not require the time and resources of a university degree. For those who seek their fortunes fast will certainly benefit from underwater welding careers.

Underwater welders are in high demand and will continue to be so for the foreseeable future, which affords a certain level of career security for those engaging in this exciting field.


Underwater welding certainly has its dangers and its inherent hazards and may not be for everyone as a career option. However, you cannot deny that the job provides tremendous excitement and travel opportunities and is a lucrative field. Wasting years behind the same desk has its hazards; just think of stress-related diseases of stationary office life!