At Henlex, we have been protecting welders and their coworkers from welding fumes for over 40 years. Fumes are formed when a metal is heated above its boiling point, and its vapors condense into very fine particles. Their size ranges from 0.005 to 20 µm, but most are smaller than 1 µm and may deposit throughout the respiratory system. Nowadays, almost every welder is aware that welding fume is toxic. But did you know that it is also carcinogenic?

According to a publication from the International Agency for Research on Cancer (IARC), welding fumes are a group 1 carcinogenic to humans. In addition, the American Conference of Governmental Industrial Hygienists (ACGIH) has classified multiple substances found in welding fume as carcinogenic.

This article will share conclusions from different research projects and a list of common carcinogenic substances commonly found in welding fume. We will also give tips to protect welders from cancer and other health issues.

Welding fume is carcinogenic

In 1989, the International Agency for Research on Cancer, an agency of the World Health Organization, had already classified welding fumes as potentially carcinogenic. At the time, they had a good idea that it was the case but were missing the data and evidence to prove it scientifically.

But in 2017, the IARC finally declared that welding fumes are carcinogenic to humans, regardless of the process used or the type of metal welded. In addition, the Centers for Disease Control and Prevention, part of the National Institute for Occupational Safety and Health (NIOSH), have acknowledged these findings and published them on their website.

Welding fume is now considered a known carcinogen that can lead to lung cancer and is classified as a group 1 carcinogen, the agency’s designation for agents carrying sufficient evidence of human carcinogenicity.

Potential cancer-causing agents found in welding fume

The American Conference of Governmental Industrial Hygienists is a well-respected organization in North America. Here is how they classify metals and gases commonly found in welding fume.

Chromium (VI)A1
Titanium dioxideA3
Vanadium pentoxideA3
Chromium (III)A4
Iron OxideA4
Nickel (soluble compound)A4
Nitrogen dioxideA4
Nickel (metal)A5
A1 = Confirmed human carcinogen
A2 = Suspected human carcinogen
A3 = Confirmed animal carcinogen with unknown relevance to human
A4 = Not classifiable as a human carcinogen
A5 = Not suspected as a human carcinogen

Arsenic is used to manufacture alloys, generally lead or copper. It can sometimes be found in welding fume and is classified as a confirmed human carcinogen.

Beryllium can be found in welding fume as it is used as a hardening agent for copper, nickel, magnesium, and aluminum alloys, as well as for electrical contacts (high heat capacity). It is a confirmed human carcinogen and one of the agents causing metal fume fever.

Hexavalent chromium can be found in fumes when welding most stainless steels and high-alloy materials. Chromium is also used in the composition of welding rods or as a plating material. It is converted to a hexavalent state by high temperatures. Hexavalent chromium is a known carcinogen for humans.

Cadmium oxides can be found in welding fume as some stainless steels and zinc alloys contain cadmium. It is also used in coatings and plating. Cadmium is also present as an impurity in non-ferrous metals (zinc, lead, and copper), iron, and steel. It is classified as a suspected human carcinogen.

Cobalt, Lead, Molybdenum, Titanium dioxide, and Vanadium pentoxide are classified as confirmed animal carcinogens with unknown relevance to humans. More studies will need to confirm the effects on human beings.

If you have any questions about welding fume, do not hesitate to contact us. We will be happy to give you some insight, and we can even visit you for free in the US and Canada.

Henlex Inc.

Risk and types of cancer caused by welding fume

Scientific research has proven lung cancer is more common among welders than non-welders. But there is evidence that welding also increases the risk of other types of cancer, such as mesothelioma, throat cancer, bladder cancer, and kidney cancer.

An article published in 2017 in Saf Health Work showed welders were likely more at risk of developing lung cancer, mesothelioma, bladder cancer, and kidney cancer. Although more research would be needed to prove that without any doubt, especially to disentangle welding effects from smoking and asbestos exposure, they observed a 16% excess risk of lung cancer among welders and a 78% greater risk of mesothelioma than non-welders. They also found that welding may contribute to the 40% increased risk of bladder cancer and the 30% increased risk of kidney cancer.

As mentioned earlier, the International Agency for Research on Cancer has also found that breathing welding fume increases lung cancer risk.

Moreover, according to the Cancer Council, exposure to welding fume and UV radiation increases the risk of developing melanoma of the eye, lung, and other cancers. They state that scientific evidence suggests exposure to all welding fume, including mild steel welding fume, can cause lung cancer. There is also limited evidence linked to kidney cancer.

Over the past years, many other studies have shown that welding increases cancer risk, especially lung cancer. A quick search on PubMed will give you many results proving this point.

It is essential to understand that the risk of getting cancer from welding depends on many factors, including:

  • the welding process and power settings;
  • the material being welded (including the plating, solvents, and coatings such as paint or lubricants);
  • the consumables (electrode, wire, etc.);
  • the shielding gas or flux;
  • the working conditions and environment (outside, inside, confined space);
  • the overall air quality in the working area;
  • the fume extraction and ventilation efficiency;
  • the welder’s positioning to avoid breathing fume and gases;
  • the use of personal protective equipment;
  • the time spent welding during the day;
  • the number of welding days per week;
  • the number of years spent welding;
  • the worker’s health condition.

Other health issues caused by welding fume

According to OSHA, the Centers for Disease Control and Prevention, the International Agency for Research on Cancer, and the CNESST (Canada), breathing welding fumes could cause the following health effects:

  • Eye, nose, and throat irritation
  • Dizziness and nausea
  • Breathing difficulties that could lead to suffocation or asphyxiation
  • Metal fume fever
  • Lung damage
  • Stomach ulcers
  • Kidney damage
  • Nervous system damage
  • Manganism (a neurological condition with Parkinson–like symptoms caused by manganese fume)
  • Chest pain
  • Asthma
  • Bleedings
  • Dermatitis or eczema
  • Kidney disease
  • Bone and joint disorders
  • Siderosis (iron oxide in lung tissue after inhalation)
  • Stannosis (tin oxide in lung tissue after inhalation)
  • Anthracosis (poisoning after inhalation of carbon dust)
  • Berylliosis (poisoning after inhalation of beryllium dust)
  • Accumulation of fluid in the lungs

Learn more about the dangers and toxicity of welding fumes.

Prevent cancer and other health issues from welding

Here are a few tips to sustainably protect welders and other workers around from cancer and other health problems caused by welding fume:

  1. Only weld when it is necessary. Other processes can sometimes replace manual welding (bolts, fasteners, robotic welding).
  2. Isolate welding operations from other workers (have an area or building dedicated to welding only, for example, or at least use welding screens).
  3. Use welding processes that produce less fume, such as submerged arc, TIG, and resistance welding. On the other hand, MIG and flux core tend to generate more fume. You could also change the power settings to reduce fumes.
  4. Use consumables and materials that produce less toxic fume. For example, you should remove paint or coatings. Avoid carcinogenic substances (arsenic, beryllium, hexavalent chromium, etc.) and hazardous metals (manganese, etc.).
  5. Use welding fume extractors. For more information, see our general article about welding fume extractors or MIG welding fume extraction if that’s the process you are using.
  6. Make sure welders position themselves to avoid breathing fumes and gases. For example, they should not leave their head between the weld pool and the fume extractor. Or they can use the wind to drive the fumes away when welding outside.
  7. Make sure your factory is adequately ventilated.
  8. Use personal protective equipment such as masks and respirators if the previous measures are insufficient to reduce exposure to safe levels. They should be fitted for each worker individually.

Learn more about our step-by-step method to solve welding fume problems.

Permissible exposure limits for welding fume, metal fume, and gases are regulated and are enforced by health and safety agencies like OSHA everywhere In North America. To know more about the maximum concentrations allowed, you can read one of the following articles:

In these articles, you will also find recommendations from the American Conference of Governmental Industrial Hygienists (ACGIH).

Any Questions?

Feel free to contact us. We will help you protect your workers and comply with welding fumes standards anywhere in the US and Canada.