Does Welding Produce Ozone? Why This Is So Important

The more I’ve been learning about welding, the more I’ve looked into the safety of it. So I started to wonder if welding produces ozone – a toxic gas.

So does welding produce ozone? Ozone is produced during welding, and it forms in the welding arc, typically during TIG, MIG, and plasma-arc welding. Ozone is a highly toxic and chemically reactive gas and is known to cause lung damage. But there are a lot of variables that contribute to production and exposure, and there are ways to protect yourself.

This article explains how welding processes produce ozone and other gases. It also contains the health risks associated with ozone exposure and the recommended safety measures for protecting workers.

How Does Welding Produce Ozone?

The arc welding process generates hazardous gases, and ozone is one of them. Ozone is created by the welding arc and the resulting ultraviolet radiation from the oxygen in the surrounding air. Oxygen molecules are split into oxygen atoms.

From there, the free atoms combine with another oxygen molecule to form ozone. The intensity of the UV radiation depends on the intensity. When the intensity is sufficient, ozone forms.

While there are several types of welding processes, the two that generate the highest levels of ozone are Metal Inert Gas (MIG) welding and tungsten Inert Gas (TIG) welding.

Inert Gas (MIG) Welding

MIG welding, or Gas Metal Arc Welding (GMAW) as it is sometimes called, is faster than other types of shielded arc welding. Welders can use it for most metal types, including copper, nickel, stainless steel, and their alloys. MIG welding is widely used throughout the industry. For example, it’s often used on pressure vessels, vehicles, bridges, and cranes.

The MIG process combines the flow of an electric arc between the base metal with a continuous, spool-fed, consumable electrode. The electrode has no flux coating or core because the shielding gas is externally supplied. The shielding gas is usually a mixture of argon and carbon monoxide.

While MIG welding produces fewer fumes because it lacks the flux coating, the intense current levels result in high levels of nitrogen oxides and O3.

Tungsten Inert Gas (TIG) Welding

Also known as Gas Tungsten Arc Welding (GTAW), Welders perform TIG welding on metals like aluminum, carbon steel, magnesium, brass, stainless steel, copper-nickel alloys, and silver. This method is often used for welding thin metals or light metals like magnesium alloys and aluminum and copper.

TIG welds resist corrosion and cracking. Also, because the heat concentration covers a small zone, the result is a quality weld with low thermal distortion.

TIG welding employs a non-consumable tungsten electrode. The welder feeds the filler metal manually. As with MIG welding, the shielding gas is externally supplied. High electrical currents are in play here, which means this method also generates high levels of nitric oxide, ozone, and nitrogen dioxide.

According to the US Bureau of Labor Statistics, there were over 377,250 welders, solderers, cutters, and brazers employed in the United States in 2017. These workers are exposed to toxic fumes produced because of welding processes.


Welding produces contaminants like ozone that can cause

short and long-term health issues if working conditions are not adequately controlled. Some of those health issues include respiratory ailments, lung infections, and certain types of lung cancer.

Ozone (O3) is a toxic gas that can damage a person’s lungs. Oxygen in the air around the welding areas produces ozone. Controlling ozone exposure is a challenge.

How Much Ozone Is Produced In Welding?

Ozone is created when the UV light from the welding arc combines with the oxygen in the air. It’s difficult to say how much ozone is produced in welding because it depends on the exact situation – namely, the metals used.

Ozone is created when the UV light from the welding arc combines with the oxygen in the air. It’s difficult to say how much ozone is produced in welding because it depends on the exact situation – namely, the metals used.

Here are a few things to know:

  • Metal inert gas (MIG) welding of aluminum alloys, using silicon and aluminum filler wire will produce the highest level of ozone.
  • If you switch to an aluminum-only filler wire, it’ll produce less ozone than the silicon/aluminum filler wire.
  • Using a magnesium and aluminum filler wire will produce the lowest amount of ozone.

Remember that ozone is only produced in the welding arc. Once the welding arc dissipates, ozone will quickly dissipate as well.

This means that to stay as safe as possible, limit your exposure to ozone when welding to 15 minutes, and keep the total exposure limit to 0.2 parts per million.

It’s actually pretty rare to see this level of exposure – both in time and parts per million – for ozone in a normal working environment.

As long as you’re following standard safety precautions and not continuously producing a welding arc (or frequently using filler wire and alloys that produce a large amount of ozone), you should generally be safe.

Risks Associated With Ozone Exposure

According to the US Occupational Safety and Health Administration’s (OSHA) Fact Sheet regarding Controlling Hazardous Fumes and Gases during Welding, exposure to ozone and other gases causes both short-term and long-term health effects.

Short-Term Health Effects

Exposure to welding gases and fumes can cause eyes, throat, and nose irritation. It can also cause nausea and dizziness. Welders with these symptoms should leave the work area right away, and then seek medical attention.

Irritated Throat and Chest

The TIG welding process involving stainless steel and aluminum, which generates ozone, irritates the throat and chest. The fine particles and gases in welding fume can make the throat feel dry or cause coughing or a feeling of tightening of the chest.

Metal Fume Fever

Often, welders describe having flu-like symptoms after welding. The effects seem worse at the beginning of the workweek. While this condition has no lasting impact, there is enough exposure to cause illness (8).

Temporarily Reduced Lung Function

General lung capacity and the peak flow of breathing are affected by sustained exposure to fumes. The effects get worse as the workweek progresses and improve once exposure ends. (8)

Long-term Health Effects

Extended exposure to fumes and ozone can damage the lungs permanently, causing chronic respiratory issues. In the worst cases, cancer develops.

Cancer Risk

Ozone is identified as a carcinogenic per the Technical Rules for Hazardous Substances (TRGS 905). Welders are at increased risk for lung cancer and larynx and urinary tract cancer.


Welders are susceptible to lung infections that can sometimes lead to severe and potentially fatal pneumonia. Standard antibiotics usually stop the virus before it becomes life-threatening. Though, in severe cases, patients are hospitalized or worse. This applies to those welders still on the job. If a person was exposed to ozone fumes, it does not mean they are at risk of pneumonia now.


Health and Safety Executive (HSE) research shows that welders have a higher-than-normal diagnosis of asthma compared to other occupations. Exposure to stainless steel fumes is believed to be the culprit because they contain nickel oxide and chromium oxide (CrO3). Both chemicals are linked with asthma.

Other Respiratory Issues

Welders may also experience chronic respiratory illnesses such as emphysema, bronchitis, pneumoconiosis, silicosis, and siderosis.

Pneumoconiosis is a dust-related disease that causes decreased lung capacity. Silicosis is another illness that occurs when the silica is exposed to welding fumes. Finally, siderosis is another dust-related disease, which is caused when the lungs are exposed to iron oxide.

Other Health Risks

Other health problems connected to welding are skin diseases, heart disease, hearing loss, and gastritis, which is chronic inflammation of the stomach. Likewise, gastroduodenitis is a related ailment in which the stomach and small intestine become inflamed. Sometimes, that develops into ulcers of the stomach and small intestines.

Welding also has reproductive risks, especially for those who work with stainless steel. Studies show that male welders have lower sperm quality than men in other professions. Additional studies show that welders and their spouses experience a higher percentage of delayed conception and miscarriages.

Recommended Safety Procedures

Reducing or even eliminating the worker’s exposure to fumes and gases is the best way to ensure the welder’s safety in the work environment. Welders must understand the hazards associated with the materials they work with daily.

OSHA’s Hazard Communication Standard states that employers must provide training and information on hazardous materials in the workplace. For welders, this includes the O3 and other gases emitted during the MIG and TIG welding processes.

OSHA recommends welders adhere to these best practices:

  • The welding surface should be cleaned to remove coatings that might add another toxic element to the process. Examples would be solvent residue or paint.
  • Welders should position themselves to avoid breathing in the welding gases and fumes. One way is to simply stay upwind when welding outside or in open environments.
  • The ventilation, whether it be natural or forced, should allow for fresh air to move freely. Such air movement reduces gases and fumes in the workspace.
  • Welding outside or in an open area doesn’t mean there’s adequate ventilation. If the work area lacks ventilation or a formal exhaust system, the welder should take advantage of natural drafts to avoid gases and fumes.
  • If there is an exhaust system, it can remove gases and fumes from the worker’s breathing zone. The system should be configured, so the following components are near the plume source: The fume hoods, vacuum nozzles, and fume extractor guns. This enables the system to take away the max amount of gases and fumes from the area.
  • If there is a flexible or portable exhaust system in place, place it so the gases and fumes move away from the welder. Exhaust ports should not be near the other workers.
  • Substitute for a welding type that’s less toxic or one that generates fewer fumes.
  • Welders should not weld in confined spaces or spaces with no ventilation.
  • If these practices and recommended ventilation don’t reduce exposure sufficiently, welders should wear respiratory protection to ensure their safety while on the job.

Related Questions

What are the dangers of welding stainless steel?

Welding stainless steel is actually strongly believed to have significant repercussions on the physical health of welders along with individuals within the welding workspace. Cr(VI) fume is really actively toxic and can undoubtedly damage the eyes, skin, nose, windpipe, as well as lungs and is possibly cancer-causing.

What are the welding fume exposure limits?

In the past, OSHA provided zero limits concerning direct exposure to welding fumes. Welding fumes are simply defined as fumes developed due to the manual metal arc, as well as oxy-acetylene welding of ironware, light steel, or even lightweight aluminum. The ACGIH has already placed an 8-Hour TWA of 5 mg/m3 for these welding fumes, quantified as total air particles within the welder’s inhalation area.