We have been a pioneer in North America, supplying welding fume extraction solutions since the 1980s. In this blog post, we’re going to shed light on the exposure limits in Ontario pertaining to some of the most frequent hazardous metals and gases found in welding fume.
Fumes arise when a metal is heated beyond its boiling point, and its vapors cool down to form very fine particles. These particles range in size from 0.005 to 20 µm, but the majority are less than 1 µm and can end up in the respiratory system.
The composition of the fume is determined by factors like the material being welded, the electrode, the coatings, the flux, and the shielding gas, among others. Air sampling is typically needed to identify the hazardous and regulated substances in your work environment. However, obtaining information on the composition of metals, gases, and consumables used in the welding process can be a helpful starting point.
Which particles in welding fume can be potentially hazardous?
Here’s a rundown of some of the harmful metals and gases that are commonly present in welding fume and will be discussed on this page:
- Aluminum
- Antimony
- Arsenic
- Beryllium
- Cadmium
- Chromium
- Cobalt
- Copper
- Iron oxide
- Lead
- Manganese (learn more about manganese in welding fumes)
- Molybdenum
- Nickel
- Silver
- Tin
- Titanium dioxide
- Vanadium
- Zinc
- Argon
- Carbon Dioxide
- Carbon Monoxide
- Helium
- Hydrogen Fluoride
- Nitric Oxide
- Nitrogen
- Nitrogen Dioxide
- Ozone
- Phosgene
Ontario Regulation 833, Control of Exposure to Biological or Chemical Agents – Welding Fume
In Ontario, as per section 4 of Regulation 833, Control of Exposure to Biological or Chemical Agents, employers have the responsibility to restrict the exposure of workers to specific hazardous biological or chemical agents.
“Every employer shall take the measures required by that section to limit the exposure of workers to a hazardous biological or chemical agent in accordance with the following rules:
1. If the agent is listed in the Ontario Table, exposure shall not exceed the TWA, STEL, or C set out in the Ontario Table.
2. If the agent is not listed in the Ontario Table but is listed in the ACGIH Table, exposure shall not exceed the TWA, STEL, or C set out in the ACGIH Table.
3. If the Table that applies under paragraph 1 or 2 sets out a TWA for an agent but sets out neither a STEL nor a C for that agent, exposure shall not exceed the following excursion limits: Three times the TWA for any period of 30 minutes. Five times the TWA at any time.”
Moreover, Regulation 833 asserts that: “An employer shall protect workers from exposure to a hazardous biological or chemical agent without requiring them to wear and use a respirator.” This implies that welding fume extractors should be deployed to remove pollutants at the source.
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Ontario – Occupational Exposure Limits for Welding Fume, Metals, and Gases
In compliance with Regulation 833, the following are the applicable Occupational Exposure Limits (OEL) in Ontario for welding fume and some of its constituents.
The abbreviations employed in the tables below are:
- TWA: The Time-Weighted Average concentration for an 8-hour workday and a 40-hour workweek
- STEL: Short-Term Exposure Limit (maximum time-weighted average concentration for 15 minutes, no more than four times per day, with at least 60 minutes in between)
- C: Ceiling (concentration never to be exceeded)
- (i): Inhalable dust (smaller than 100 µm)
- (r): Respirable dust (smaller than 4 µm)
| OEL | TWA | STEL | C |
| Welding Fumes* | 10mg/m3(i) 3mg/m3(r) | None | None |
| OEL | TWA | STEL | C |
| Aluminum | 1mg/m3(r) | None | None |
| Antimony | 0.5mg/m3 | None | None |
| Arsenic | 0.01mg/m3 | 0.05mg/m3 | None |
| Beryllium | 0.05µg/m3(i) | None | None |
| Cadmium | 0.01mg/m3 | None | None |
| Chromium metal & (III) | 0.5mg/m3 | None | None |
| Chromium (VI) | 0.01mg/m3 | None | None |
| Cobalt | 0.02mg/m3 | None | None |
| Copper | 0.2mg/m3 | None | None |
| Iron Oxide | 5mg/m3(r) | None | None |
| Lead | 0.05mg/m3 | None | None |
| Manganese | 0.2mg/m3 | None | None |
| Molybdenum | 3mg/m3(r) 10mg/m3(i) | None | None |
| Nickel | 1mg/m3(i) | None | None |
| Silver | 0.1mg/m3 | None | None |
| Tin metal & oxide | 2mg/m3 | None | None |
| Titanium dioxide | 10mg/m3 | None | None |
| Vanadium pentoxide | 0.05mg/m3(i) | None | None |
| Zinc oxide | 2mg/m3(r) | 10mg/m3(r) | None |
| OEL | TWA | STEL | C |
| Argon* | None | None | None |
| Carbon Dioxide | 5,000ppm | 30,000ppm | None |
| Carbon Monoxide | 25ppm | None | None |
| Helium* | None | None | None |
| Hydrogen Fluoride | 0.5ppm | None | 2ppm |
| Nitric Oxide | 25ppm | None | None |
| Nitrogen* | None | None | None |
| Nitrogen Dioxide | 3ppm | 5ppm | None |
| Ozone | None | None | 0.1ppm |
| Phosgene | 0.1ppm | 0.3ppm | None |
Remember, as per the Regulations, “if the Table […] sets out a TWA for an agent but sets out neither a STEL nor a C for that agent, exposure shall not exceed the following excursion limits: Three times the TWA for any period of 30 minutes. Five times the TWA at any time.”
ACGIH – Threshold Limit Values for Welding Fume, Metals, and Gases
The American Conference of Governmental Industrial Hygienists (ACGIH) is a significant organization that studies hazardous substances and suggests exposure limits. Their recommended Threshold Limit Values (TLV) are influential for most health and safety organizations in North America and are crucial to understand.
Threshold Limit Values are protected by copyright from ACGIH and can’t be reproduced on other websites. Nonetheless, links to the pertinent pages on their website are provided below.
The ACGIH hasn’t given a specific recommendation regarding welding fumes as a whole. Consequently, they are classified under the Particulates Not Otherwise Regulated category. In this instance, the ACGIH recommendation is a TLV-TWA of 3mg/m3 for respirable particles and 10mg/m3 for inhalable particles.
- Aluminum
- Antimony
- Arsenic
- Beryllium
- Cadmium
- Chromium
- Cobalt
- Copper
- Iron Oxide
- Lead
- Manganese
- Molybdenum
- Nickel
- Silver
- Tin, organic
- Tin oxide & inorganic
- Titanium
- Vanadium
- Zinc Oxide
- Argon*
- Carbon Dioxide
- Carbon Monoxide
- Helium*
- Hydrogen Fluoride
- Nitric Oxide
- Nitrogen*
- Nitrogen Dioxide
- Ozone
- Phosgene
* A concentration limit is not included because available oxygen is the limiting factor.
Health risks associated with breathing welding fumes
According to OSHA, the Centers for Disease Control and Prevention, the International Agency for Research on Cancer, and the CNESST (Quebec), 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
These are good reasons to protect welders, meet the standards, and even extract pollutants as efficiently as possible. Welding fume extractors will be the best way to do so.
To learn more about welding fume regulations in another Canadian province or territory, feel free to use one of the links below to be directed to our article on the subject:
- Alberta
- British Columbia
- Manitoba
- Newfoundland and Labrador
- New Brunswick
- Northwest Territories
- Nova Scotia
- Nunavut
- Prince Edward Island
- Quebec
- Saskatchewan
- Yukon
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.
1-866-800-8421
info@airgomig.com