Although many factors must be considered to know how much welding fume could be dangerous for a specific person, there are clear guidelines and legislation to protect welders. In addition, more studies about the dangers of welding fume come out every year and help health and safety organizations establish safe levels of exposure.

In the United States, the permissible exposure limit for welding fume enforced by OSHA and Cal/OSHA is 5 mg/m3. It is the 8 hours time-weighted average. Many hazardous substances found in welding fumes are also subjected to their exposure limit, such as chromium, manganese, etc.

In Canada, health and safety agencies in the Northwest Territories, Nunavut, Quebec, Saskatchewan, and Yukon set the exposure limit for welding fume at 5 mg/m3. Other provinces and territories follow the ACGIH recommendations, except for Alberta that requires to keep it as low as reasonably possible.

The National Institute for Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH) are constantly researching this issue to establish the best recommendations to protect workers.

How much welding fumes can you breathe in before it becomes harmful?

Health and safety organizations in North America recommend an exposure limit for welding fume between 3 and 10 mg/m3 as a time-weighted average for eight hours. This concentration is nowadays considered safe. However, they recommend reducing the exposure as much as possible to avoid health problems.

For multiple reasons, it is complicated to give a definitive answer as to how much welding fume is safe. It depends on the following:

  • The health of the welder or worker breathing them. People with pre-existing medical conditions, such as cardiorespiratory disease, are more at risk of developing health problems.
  • The welding fume itself. Not all fumes are equal. Some can be a lot more dangerous than others. For example, they can contain carcinogenic substances, such as arsenic, beryllium, or hexavalent chromium. The level of manganese is also a critical factor as it can cause Manganism (a neurological condition causing Parkinson–like symptoms).
  • The work environment and conditions. Welding in a confined or poorly ventilated area increases the risk. The same goes for people welding for more than 8 hours per day or working in a hot environment.

The consensus is that employers should always do everything that is reasonably possible to reduce their workers’ exposure to welding fume. They should at least ensure that all the hazardous metals and gases are kept below the permissible exposure limits, or even better, try to follow the American Conference of Governmental Industrial Hygienists (ACGIH) recommendations.

Safe levels of welding fume according to the ACGIH

The American Conference of Governmental Industrial Hygienists is a well-respected organization in North America. Although their recommendations cannot be enforced, many health and safety agencies use them to establish permissible exposure limits. When talking about how much welding fume can be harmful, one should consider their Threshold Limit Values (TLVs).

TLVs are copyrighted by ACGIH and cannot be reproduced on other websites. However, you will find the links to the relevant pages on their website below.

ACGIH has not yet published a recommendation regarding welding fumes in general. Therefore, they fall under the Particulates Not Otherwise Regulated category. The ACGIH recommends a TLV of 3mg/m3 for respirable particles and 10mg/m3 for inhalable particles.

Metals: Aluminum, Antimony, Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron Oxide, Lead, Manganese, Molybdenum, Nickel, Silver, Tin oxide & inorganic, Titanium, Vanadium, Zinc Oxide,

Gases: Argon, Carbon Dioxide, Carbon Monoxide, Helium, Hydrogen Fluoride, Nitric Oxide, Nitrogen, Nitrogen Dioxide, Ozone, Phosgene.

Permissible levels of welding fumes

Abbreviations used in the tables below:

  • ALARA: Exposure must be kept As Low As Reasonably Achievable
  • TWA: The Time-Weighted Average concentration for an 8-hour workday
  • STEL: Short-Term Exposure Limit (maximum time-weighted average concentration for 15 minutes)
  • C: Ceiling (concentration never to be exceeded)
  • (r): Respirable portion
  • (i): Inhalable portion

Regulations in the US

Welding FumesTWASTELC

To see the permissible exposure limits for more metals and gases, you can read one of the two following articles:

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.

Regulations in Canada

Welding FumesTWASTELC
British Columbia 10mg/m3 (i)
3mg/m3 (r)
Manitoba10mg/m3 (i)
3mg/m3 (r)
New Brunswick 10mg/m3 (i)
3mg/m3 (r)
Newfoundland and Labrador 10mg/m3 (i)
3mg/m3 (r)
30 mg/m3*
9 mg/m3*
50 mg/m3
15 mg/m3
Northwest Territories5mg/m310 mg/m3None
Nova Scotia10mg/m3 (i)
3mg/m3 (r)
Ontario10mg/m3 (i)
3mg/m3 (r)
Prince Edward Island10mg/m3 (i)
3mg/m3 (r)
* For 30 minutes during a workday.

For more information and hazardous substances that can be found in welding fume, read: Welding Fume Regulations and Exposure Limits in Canada

Avoid inhaling welding fumes and stay healthy

Here are a few tips to sustainably prevent health problems caused by welding fumes:

  1. Only weld when it is necessary. Other processes can sometimes replace manual welding.
  2. Isolate welding operations from other workers (have an area or building dedicated to welding only, for example).
  3. Use welding processes and materials that produce less toxic fume. Some welding wires have been designed to be less toxic, for example. Try also to avoid carcinogenic substances (arsenic, beryllium, hexavalent chromium, etc.).
  4. 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.
  5. 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.
  6. Make sure your factory is adequately ventilated.
  7. Use personal protective equipment such as masks if the previous measures are insufficient to reduce exposure to safe levels.

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

Do welders have health problems?

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 and various types of cancer
  • Stomach ulcers
  • Kidney damage
  • Nervous system damage
  • Manganism
  • 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.

Signs and symptoms that you’ve breathed in toxic fumes

The first indicators that one has been breathing hazardous welding fumes are eye, nose, or throat irritation, dizziness, nausea, breathing difficulties, and metal fume fever (flu-like symptoms that typically occur 4 to 10 hours after exposure and disappear after 12 to 48 hours).

If you feel any symptoms, the best thing to do is get some fresh air and hydrate. However, if you have difficulty breathing or if the symptoms worsen, persist, or reappear, you should seek medical attention to get a diagnosis and take any steps necessary to recover.

We have a whole article about what to do if you inhale welding fumes if you want to know more.

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.