Welding Fumes: Determining Safe Exposure Limits and Tips for Welder Safety

Determining the exact level of welding fume that could pose a danger to an individual requires an analysis of numerous variables. However, well-defined regulations and laws have been put in place to protect welders. Further, as ongoing research continues to reveal the hazards associated with welding fumes, health and safety organizations are better able to define safe exposure levels.

According to OSHA and Cal/OSHA regulations in the United States, the permissible welding fume exposure limit is 5 mg/m3, as an eight-hour time-weighted average. It’s important to note that harmful substances commonly present in welding fumes, such as chromium and manganese, have their own exposure limits as well.

In Canada, health and safety authorities in Northwest Territories, Nunavut, Quebec, Saskatchewan, and Yukon enforce an exposure limit for welding fume at 5 mg/m3. Other provinces and territories follow the guidelines provided by the ACGIH, with the exception of Alberta, which promotes minimizing exposure as much as possible.

Both the National Institute for Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH) continue to investigate this matter, working towards the optimal guidelines to protect the workforce.

How much welding fume exposure is safe?

The recommended welding fume exposure limits set by North American health and safety organizations range between 3 and 10 mg/m3 over an eight-hour time-weighted average. These levels are currently deemed safe. However, they advise keeping exposure as low as possible to avert health complications.

Giving an absolute answer to the amount of welding fume that is safe is complex due to several factors:

• The health of the welder or person inhaling the fumes. Individuals with existing health issues like cardio respiratory disease are more susceptible to health complications.
• The nature of the welding fume. Fumes differ significantly, with some being considerably more hazardous than others. Some fumes can contain cancer-causing agents such as arsenic, beryllium, or hexavalent chromium. Also, the manganese level is critical as it can induce Manganism (a neurological disorder inducing Parkinson-like symptoms).
• The working conditions and environment. Welding in an enclosed or inadequately ventilated space heightens the risk, as does welding for more than eight hours daily or working in high-temperature conditions.

The consensus is that employers should undertake every feasible measure to minimize their workers’ exposure to welding fumes. They should ensure all hazardous metals and gases remain below permissible exposure limits and, ideally, align with the American Conference of Governmental Industrial Hygienists (ACGIH) guidelines.

ACGIH’s recommended welding fume levels

The American Conference of Governmental Industrial Hygienists holds considerable respect in North America. While their recommendations are not legally binding, many health and safety organizations use them to set exposure limits. When discussing potentially harmful welding fume levels, one should consider their Threshold Limit Values (TLVs).

These TLVs, copyrighted by the ACGIH, cannot be replicated on other sites. However, the relevant page links can be found on their website.

ACGIH has yet to release a specific recommendation on welding fumes, so they currently fall under the Particulates Not Otherwise Regulated category. For respirable and inhalable particles, the ACGIH suggests TLVs of 3mg/m3 and 10mg/m3 respectively.

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 Fumes	TWA	STEL	C
OSHA	5mg/m3(r)	None	None
Cal/OSHA	5mg/m3	None	None

Manganese	TWA	STEL	C
OSHA	None	None	5mg/m3
Cal/OSHA	0.2mg/m3	3mg/m3	None

Chromium (VI)	TWA	STEL	C
OSHA	5µg/m3	None	None
Cal/OSHA	5µg/m3	None	0.1mg/m3

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

• Welding Fume Regulations and Exposure Limits in the US
• Welding Fume Regulations and Exposure Limits in California

Regulations in Canada

Welding Fumes	TWA	STEL	C
Alberta	ALARA	ALARA	ALARA
British Columbia	10mg/m3 (i) 3mg/m3 (r)	30mg/m3* 9mg/m3*	50mg/m3 15mg/m3
Manitoba	10mg/m3 (i) 3mg/m3 (r)	None	None
New Brunswick	10mg/m3 (i) 3mg/m3 (r)	None	None
Newfoundland and Labrador	10mg/m3 (i) 3mg/m3 (r)	30 mg/m3* 9 mg/m3*	50 mg/m3 15 mg/m3
Northwest Territories	5mg/m3	10 mg/m3	None
Nova Scotia	10mg/m3 (i) 3mg/m3 (r)	None	None
Nunavut	5mg/m3	10mg/m3	None
Ontario	10mg/m3 (i) 3mg/m3 (r)	30mg/m3* 9mg/m3*	50mg/m3 15mg/m3
Prince Edward Island	10mg/m3 (i) 3mg/m3 (r)	None	None
Quebec	5mg/m3	15mg/m3*	25mg/m3
Saskatchewan	5mg/m3	10mg/m3	None
Yukon	5mg/m3	5mg/m3	None

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

Preventing Exposure to Welding Fumes: A Healthy Approach

Here are some strategies to help mitigate health problems due to welding fumes:

1. Opt for welding only when it’s essential. Alternative processes can often replace manual welding.
2. Isolate welding tasks from other workers (for instance, dedicate an area or building solely to welding).
3. Choose welding processes and materials that generate less harmful fume. Some welding wires are designed to be less toxic. Also, avoid carcinogenic substances (such as arsenic, beryllium, hexavalent chromium, etc.).
4. Use welding fume extractors. For further details, see our comprehensive article on welding fume extractors or MIG welding fume extraction if that’s the process you use.
5. Train welders to position themselves to avoid inhaling fumes and gases. For example, they should not place their heads between the weld pool and the fume extractor. Or, when welding outdoors, use the wind to blow the fumes away.
6. Ensure the workspace is well-ventilated.
7. Supply personal protective equipment like masks if other measures don’t sufficiently reduce exposure to safe levels.

Discover our step-by-step method to solve welding fume problems.

Do Welders Experience Health Issues?

OSHA, the Centers for Disease Control and Prevention, the International Agency for Research on Cancer, and the CNESST (Canada) suggest that inhaling welding fumes can lead to the following health outcomes:

• 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.

Recognizing the Signs and Symptoms of Toxic Fume Inhalation

Early signs of toxic welding fume inhalation include irritation of the eyes, nose, or throat, dizziness, nausea, breathing difficulties, and metal fume fever (flu-like symptoms that usually appear 4 to 10 hours after exposure and disappear after 12 to 48 hours).

If you experience any symptoms, it’s advisable to move to a well-ventilated area and hydrate. If breathing becomes difficult or symptoms persist, worsen, or recur, seek medical attention for a diagnosis and to initiate necessary treatment steps.

For more detailed information, you can refer to our extensive article what to do if you inhale welding fumes.

Any Questions?

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