Last updated in June 2024
We have been a pioneer in North America, providing welding fume extraction solutions since the 1980s. In this blog post, you will find the exposure limits applicable in Canada for some of the most common hazardous metals and gases found in welding fume.
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.
The fume composition depends on the material being welded, the electrode, the coatings, the flux, and the shielding gas, among other things. Air sampling is usually necessary to know which hazardous and regulated substances are in your working environment. But getting information on the composition of metals, gases, and consumables used in the welding process is usually a good start.
In Canada, there are 14 health and safety agencies. One for each of the 13 provinces and territories and a federal agency that covers federal government employees.
Health and safety regulations for federal government employees
The Canada Occupational Health and Safety Regulations (OH&S), which are part of the Canada Labour Code, apply to federal employees and employees of some companies or sectors that operate across provincial or international borders. Approximately 6% of the Canadian workforce falls under the OH&S jurisdiction of the federal government. The other workers fall under local jurisdiction.
Here are some relevant parts of the Canada Occupational Health and Safety Regulations regarding welding fumes.
“Every ventilation system installed on or after January 1, 1997, to control the concentration of an airborne hazardous substance shall be so designed, constructed, installed, operated and maintained that […] it meets the standards set out in Part 6 of the National Building Code, the publication of the American Conference of Governmental Industrial Hygienists entitled Industrial Ventilation, 20th edition, dated 1988, as amended from time to time, or ANSI Standard ANSI Z9.2-1979 entitled Fundamentals Governing the Design and Operation of Local Exhaust Systems, dated 1979, as amended from time to time. “
“An employee shall be kept free from exposure to a concentration of an airborne chemical agent […] in excess of the value for that chemical agent adopted by the American Conference of Governmental Industrial Hygienists, in its publication entitled Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs), as amended from time to time.”
You can find links to the ACGIH Threshold Limit Values at the end of this article.
The Canadian Center for Occupational Health and Safety (CCOHS) has also published a fact sheet on welding fumes and gases if you are interested.
Any questions? Ask them directly in the chat at the bottom right of your screen or during one of our webinars.

Health and safety regulations for welding fume for each province and territory
Each province and territory in Canada has its own health and safety regulations for welding fume and exposure limits for hazardous substances. In this article, we will review them one by one.
Regarding general ventilation, although not explicitly stated (except in Quebec where it is in the law), the general consensus is that a minimum of 4 air changes per hour is required for industrial buildings, including those with welding operations. In confined spaces, the minimum recommended is 10 air changes per hour, though 20 or more may be necessary.
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
- (t): Total dust
Alberta Occupational Health and Safety Code – Welding Fume
In Alberta, employers are required to follow the Occupational Health and Safety Code. Occupational Exposure Limits can be found in Schedule 1. Here is some important information.
“An employer must ensure that a worker’s exposure to any substance listed in Schedule 1, Table 2 does not exceed its occupational exposure limits listed in Schedule 1, Table 2.”
“If no occupational exposure limit is established for a harmful substance present at a work site, an employer must ensure that a worker’s exposure to that substance is kept as low as reasonably achievable.”
“If no 15-minute occupational exposure limit or ceiling occupational exposure limit is listed for a substance in Schedule 1, Table 2, the employer must comply with the 8-hour occupational exposure limit, and ensure that a worker’s exposure to that substance does not exceed 3 times the 8-hour occupational exposure limit for more than a total of 30 minutes during a continuous 24-hour period, and 5 times the 8-hour occupational exposure limit, or the concentration that is immediately dangerous to life and health, whichever is lower.”
OEL | TWA | STEL | C |
Welding Fumes | ALARA | ALARA | ALARA |
OEL | TWA | STEL | C |
Aluminum | 10mg/m3 | None | None |
Antimony | 0.5mg/m3 | None | None |
Arsenic | 0.01mg/m3 | None | None |
Beryllium | 2µg/m3 | 0.01mg/m3 | None |
Cadmium | 2mg/m3 | None | None |
Cadmium compounds | 2µg/m3(r) | 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 | None | None |
Lead | 0.05mg/m3 | None | None |
Manganese | 0.2mg/m3 | None | None |
Molybdenum | 3mg/m3(r) 10mg/m3(t) | None | None |
Nickel | 1.5mg/m3 | 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 | None | None |
Zinc oxide | 2mg/m3 (r) | 10mg/m3 | 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 | 0.1ppm | 0.3ppm | None |
Phosgene | 0.1ppm | None | None |
British Columbia Occupational Health and Safety Regulation – Welding Fume
In British Columbia, companies must follow the Occupational Health and Safety Regulation. It contains legal requirements that must be met by all workplaces under the inspectional jurisdiction of WorkSafeBC. Part 5 is about chemical and biological agents.
Section G5.48-5 is interesting as it is about welding fumes. Here are some parts to know.
“Except as otherwise determined by the Board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.”
“To determine the potential level of exposure to welding fumes, a systematic review of the base metal, consumables, and type of process is required. Typically, information on consumables is identified by reviewing documents such as the safety data sheets (SDSs) from the manufacturer. Other information, such as the composition of the metal(s) being welded or cut, the specific type of welding process, and other relevant information (e.g., current and voltage) should be gathered to assess the hazardous ingredients and expected products of reaction and decomposition.”
“Once the information on possible types of exposure has been determined, the Table of Exposure Limits for Chemical and Biological Substances should be consulted for the applicable exposure limit(s).”
“The employer must comply with the exposure limit for each of the individual constituents in the welding fume. The exposure limits for Particles Not Otherwise Classified (PNOC) of 8-hour TWA of 10 mg/m3 and respirable fraction of 3 mg/m3 do not apply as total welding fume exposure limits since welding fumes are not considered to be “nuisance dust.”
“The employer must replace substances identified as a designated substance, if practicable, with a material that reduces the risk of exposure to workers. If it is not practicable to substitute a material, then the employer must implement an exposure control plan in accordance with section 5.54 to maintain workers’ exposure as low as reasonably achievable below the exposure limit.”
Some of the individual constituents of welding fumes are also designated substances. Some of the common designated substances in welding fumes are: Hexavalent chromium oxide, Beryllium oxides, Manganese oxides, Cadmium oxide, Nickel.
WorkSafe BC also provides an informational page worth reading about welding fumes and gases. You will find a few tips on reducing the risks for workers, including using a process that generates fewer fumes, using local exhaust ventilation, improving general ventilation, etc.
Exposure Limit | TWA | STEL | C |
Chromium (0) & (III) | 0.5mg/m3 | None | None |
Chromium (VI), insoluble | 0.01mg/m3 | None | None |
Chromium (VI), soluble | 0.025mg/m3 | None | None |
Cobalt | 0.02mg/m3 | None | None |
Iron | 5mg/m3 | 10mg/m3 | None |
Manganese | 0.2mg/m3(t) 0.02mg/m3(r) | None | None |
Nickel | 0.05mg/m3 | None | None |
Silver | 0.01mg/m3 | 0.03mg/m3 | None |
Tin | 2mg/m3 | None | None |
Titanium | 10mg/m3(t) 3mg/3m(r) | None | None |
Carbon dioxide | 5,000ppm | 15,000ppm | None |
Carbon monoxide | 25ppm | 100ppm | None |
Hydrogen Fluoride | None | None | 2ppm |
Nitrogen Dioxide | None | None | 1ppm |
Phosgene | 0.1ppm | None | None |
For all the other substances discussed on this page, ACGIH TLVs apply. Threshold Limit Values 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 published a recommendation regarding welding fumes in general. Therefore, they fall under the Particulates Not Otherwise Regulated category. The ACGIH recommendation, in this case, is a TLV-TWAEV of 3mg/m3 for respirable particles (smaller than 4 µm) and 10mg/m3 for inhalable particles (smaller than 100 µm).
- Aluminum
- Antimony
- Arsenic
- Beryllium
- Cadmium
- Copper
- Lead
- Molybdenum
- Vanadium
- Zinc Oxide
- Argon*
- Helium*
- Nitric Oxide
- Nitrogen*
- Ozone
* Simple asphyxiant: a concentration limit is not included because available oxygen is the limiting factor.
Manitoba Workplace Safety and Health Act – Welding Fume
In Manitoba, companies must follow the Manitoba Workplace Safety and Health Act. Exposure limit regulations can be found in chapter 36.5. Here is some important information.
“In the case of an airborne substance for which the ACGIH has established a threshold limit value, establish an occupational exposure limit for the substance that does not exceed the threshold limit value established by the ACGIH.”
“In the case of an airborne designated material, establish an occupational exposure limit for the material that is as close to zero as possible and does not exceed the threshold limit value established by the ACGIH.”
“Designated material: a chemical or biological substance which meets the criteria as a carcinogen, mutagen, respiratory sensitizer or reproductive toxin under the Hazardous Products Regulations.”
When there is no ACGIH threshold limit value, a competent person must establish one. Some conditions in the workplace or workers’ health could require the employer to establish a lower occupational exposure limit than the one from ACGIH to ensure their safety.
In short, in Manitoba, companies must establish their Occupational Exposure Limits (OEL) to ensure their workers’ safety. They must also use the ACGIH recommendations as the maximum OEL authorized.
OEL | TWA | STEL | C |
Welding Fumes* | 3mg/m3(r) 10mg/m3(i) | None | None |
OEL | TWA | STEL | C |
Aluminum | 1mg/m3(r) | None | None |
Antimony | 0.5mg/m3 | None | None |
Arsenic | 0.01mg/m3 | None | None |
Beryllium | 0.05µg/m3(i) | None | None |
Cadmium | 2µg/m3(r) | None | None |
Chromium (0) | 0.5mg/m3(i) | None | None |
Chromium (III) | 3µg/m3(i) | None | None |
Chromium (VI) | 0.2µg/m3(i) | 0.5µg/m3(i) | None |
Cobalt | 0.02mg/m3(i) | None | None |
Copper | 0.2mg/m3 | None | None |
Iron Oxide | 5mg/m3(r) | None | None |
Lead | 0.05mg/m3 | None | None |
Manganese | 0.02mg/m3(r) 0.1mg/m3(i) | None | None |
Molybdenum | 3mg/m3(r) 10mg/m3(i) | None | None |
Nickel | 1.5mg/m3(i) | None | None |
Silver | 0.1mg/m3 | None | None |
Tin, organic | 0.1mg/m3 | 0.2mg/m3 | None |
Tin oxide & inorganic | 2mg/m3(i) | None | None |
Titanium | 0.2mg/m3(r) | None | None |
Vanadium | 0.05mg/m3(i) | None | None |
Zinc | 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 | 0.2ppm | None | None |
Ozone | 0.05ppm | None | None |
Phosgene | None | None | 0.02ppm |
New Brunswick Occupational Health and Safety Act – Welding Fume
In New Brunswick, companies must follow the Occupational Health and Safety Act. Welding regulations can be found in chapter XVIII (Welding, Cutting, and Soldering), Indoor Air Quality is chapter III and exposure limits are defined in chapter I (Interpretation). Here is some information to know.
“Occupational Exposure Limit means, except with respect to lead sulfide, formaldehyde, sulfur dioxide, hydrogen sulfide, nitrogen dioxide, and any other air contaminant for which the Commission sets an exposure limit, a threshold limit value adopted by the ACGIH and set out in the ACGIH publication entitled 2016 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices.”
“An employer shall ensure that an employee is protected from the effects of harmful fumes and gases or particles emitted from welding, cutting, burning or soldering operations by providing a local exhaust system close to the source of the fumes, gases or particles in an indoor welding, cutting, burning or soldering area, monitoring the exposure level of employees to harmful fumes and gases or particles emitted from welding, cutting, burning or soldering operations to ensure that the level of concentration of air contaminants does not exceed the occupational exposure limits, and monitoring the work areas in proximity to the welding, cutting, burning or soldering area to ensure that the level of concentration of air contaminants does not exceed the occupational exposure limits.”
“An employer shall ensure that a local exhaust ventilation system is designed so that under normal work conditions an employee’s breathing zone is not located between the source of contamination and the exhaust uptake.”
Threshold Limit Values (TLV) are copyrighted by ACGIH and cannot be reproduced on other websites. To learn more about the 2016 ACGIH TLVs, contact WorkSafeNB.

Newfoundland and Labrador Occupational Health and Safety Regulations – Welding Fume
In Newfoundland and Labrador, companies must follow the Occupational Health and Safety Regulations under the Occupational Health and Safety Act.
Information regarding Exposure Limits can be found in Part 6 (Occupational Health Requirements). However, here are a few essential parts regarding welding fume, metals, and gases.
“An employer shall ensure that
(a) atmospheric contamination of the workplace by hazardous substances is kept as low as is reasonably practicable;
(b) a worker is informed of the nature and degree of health effects of the hazardous substances to which the worker is exposed;
(c) exposure of a worker to hazardous substances is as minimal as is reasonably practicable, and where a threshold limit value has been established by the ACGIH, exposure shall not exceed the threshold limit value;
(d) except as otherwise determined by the division, a worker is not exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA (time-weighted average) limit prescribed by ACGIH; and
(e) where a substance referred to in paragraph (d) has an 8-hour TWA limit, a worker’s exposure to the substance does not exceed
(i) 3 times the 8-hour TWA limit for more than a total of 30 minutes during the work period, and
(ii) 5 times the 8-hour TWA limit.”
“TLV means the documentation of threshold limit values for chemical substances and physical agents in the work environment published annually or more frequently by the ACGIH.”
“ACGIH means the American Conference of Governmental Industrial Hygienists.”
Welding regulations can be found in Part 21 (Welding, Burning, and Cutting Operations). In addition, article 454 is specifically about ventilation.
“Effective local exhaust ventilation shall be used at a fixed work station to minimize worker exposure to harmful air contaminants produced by welding, burning or soldering.”
You can find links to the ACGIH Threshold Limit Values at the end of this article.
Northwest Territories Occupational Health and Safety Regulations – Welding Fume
Employers must comply with the Occupational Health and Safety Regulations in the Northwest Territories.
Ventilation regulations can be found in Part 6 (General Health Requirements). Here are a few relevant quotes when it comes to welding.
“An employer shall ensure the adequate ventilation of a work site; and, to the extent that is reasonably possible, render harmless, and prevent the accumulation of, any contaminants or impurities in the air by providing an adequate supply of clean and wholesome air and maintaining its circulation throughout the work site.”
“An employer shall provide a mechanical ventilation system at a work site that is sufficient and suitable to protect workers against inhalation of a contaminant and to prevent accumulation of the contaminant […] if any work, activity or process at the work site gives off a dust, fume, gas, mist, aerosol, vapour or other airborne contaminant that is hazardous to workers.”
“An employer shall, to the extent that is reasonably possible, ensure that a mechanical ventilation system […] includes local exhaust ventilation that is installed and maintained at or near the point of origin of the contaminant so as to effectively prevent the contaminant from entering the air of the work site.”
Finally, Contamination Limits can be found in Schedule O.
“If a chemical or biological substance set out in Schedule O is present at a work site, an employer shall, to the extent that is reasonably possible, provide adequate engineering controls to ensure that the contamination limit set out in Schedule O is not exceeded; and take steps to ensure that workers’ personal exposure does not exceed the contamination limits set out in Schedule O.”
CL | TWA | STEL |
Welding Fumes | 5mg/m3 | 10mg/m3 |
CL | TWA | STEL |
Aluminum | 10mg/m3 | 20mg/m3 |
Antimony | 0.5mg/m3 | 1.5mg/m3 |
Arsenic | 0.01mg/m3 | 0.03mg/m3 |
Beryllium | 2µg/m3 | 0.01mg/m3 |
Cadmium | 0.01mg/m3 | 0.03mg/m3 |
Cadmium, respirable | 2µg/m3 | 6µg/m3 |
Chromium metal and (III) | 0.5mg/m3 | 1.5mg/m3 |
Chromium (VI), soluble | 0.05mg/m3 | 0.15mg/m3 |
Chromium (VI), insoluble | 0.01mg/m3 | 0.03mg/m3 |
Cobalt | 0.02mg/m3 | 0.06mg/m3 |
Copper | 0.2mg/m3 | 0.6mg/m3 |
Iron Oxide | 5mg/m3 | 10mg/m3 |
Lead | 0.05mg/m3 | 0.15mg/m3 |
Manganese | 0.2mg/m3 | 0.6mg/m3 |
Molybdenum, inhalable | 10mg/m3 | 20mg/m3 |
Molybdenum, respirable | 3mg/m3 | 6mg/m3 |
Nickel, inhalable | 1.5mg/m3 | 3mg/m3 |
Silver | 0.1mg/m3 | 0.3mg/m3 |
Tin metal and oxide | 2mg/m3 | 4mg/m3 |
Titanium dioxide | 10mg/m3 | 20mg/m3 |
Vanadium pentoxide, respirable | 0.05mg/m3 | 0.15mg/m3 |
Zinc oxide, respirable | 2mg/m3 | 10mg/m3 |
CL | TWA | STEL | C |
Argon* | None | None | None |
Carbon Dioxide | 5,000ppm | 30,000ppm | None |
Carbon Monoxide | 25ppm | 190ppm | None |
Helium* | None | None | None |
Hydrogen Fluoride | 0.5ppm | None | 2ppm |
Nitric Oxide | 25ppm | 38ppm | None |
Nitrogen* | None | None | None |
Nitrogen Dioxide | 3ppm | 5ppm | None |
Ozone | 0.05ppm | 0.15ppm | None |
Phosgene | 0.1ppm | 0.3ppm | None |
Nova Scotia Workplace Health and Safety Regulations – Welding Fume
In Nova Scotia, companies must follow Workplace Health and Safety Regulations. Information regarding Threshold Limit Values (TLVs) can be found in Part 2 (Occupational Health).
“TLVs and BEIs means the latest version of the publication of the American Conference of Governmental Industrial Hygienists of threshold limit values and biological exposure indices.”
“An employer must comply with, and ensure compliance with, the threshold limit values for exposure to all of the following, as listed in the TLVs and BEIs: gases; vapors; mists; fumes; smoke; dust; chemical substances; physical agents.”
You can find links to the ACGIH Threshold Limit Values at the end of this article.
Nunavut Occupational Health and Safety Regulations – Welding Fume
Employers must comply with the Occupational Health and Safety Regulations in Nunavut.
Ventilation regulations can be found in Part 6 (General Health Requirements). Here are a few relevant quotes when it comes to welding.
“An employer shall ensure the adequate ventilation of a work site; and, to the extent that is reasonably possible, render harmless, and prevent the accumulation of, any contaminants or impurities in the air by providing an adequate supply of clean and wholesome air and maintaining its circulation throughout the work site.”
“An employer shall provide a mechanical ventilation system at a work site that is sufficient and suitable to protect workers against inhalation of a contaminant and to prevent accumulation of the contaminant […] if any work, activity or process at the work site gives off a dust, fume, gas, mist, aerosol, vapour or other airborne contaminant that is hazardous to workers.”
“An employer shall, to the extent that is reasonably possible, ensure that a mechanical ventilation system […] includes local exhaust ventilation that is installed and maintained at or near the point of origin of the contaminant so as to effectively prevent the contaminant from entering the air of the work site.”
Finally, Contamination Limits can be found in Schedule O.
“If a chemical or biological substance set out in Schedule O is present at a work site, an employer shall, to the extent that is reasonably possible, provide adequate engineering controls to ensure that the contamination limit set out in Schedule O is not exceeded; and take steps to ensure that workers’ personal exposure does not exceed the contamination limits set out in Schedule O.”
CL | TWA | STEL |
Welding Fumes | 5mg/m3 | 10mg/m3 |
CL | TWA | STEL |
Aluminum | 10mg/m3 | 20mg/m3 |
Antimony | 0.5mg/m3 | 1.5mg/m3 |
Arsenic | 0.01mg/m3 | 0.03mg/m3 |
Beryllium | 2µg/m3 | 0.01mg/m3 |
Cadmium, total | 0.01mg/m3 | 0.03mg/m3 |
Cadmium, respirable** | 2µg/m3 | 6µg/m3 |
Chromium metal and (III) | 0.5mg/m3 | 1.5mg/m3 |
Chromium (VI), soluble | 0.05mg/m3 | 0.15mg/m3 |
Chromium (VI), insoluble | 0.01mg/m3 | 0.03mg/m3 |
Cobalt | 0.02mg/m3 | 0.06mg/m3 |
Copper | 0.2mg/m3 | 0.6mg/m3 |
Iron Oxide | 5mg/m3 | 10mg/m3 |
Lead | 0.05mg/m3 | 0.15mg/m3 |
Manganese | 0.2mg/m3 | 0.6mg/m3 |
Molybdenum, inhalable* | 10mg/m3 | 20mg/m3 |
Molybdenum, respirable** | 3mg/m3 | 6mg/m3 |
Nickel, inhalable* | 1.5mg/m3 | 3mg/m3 |
Silver | 0.1mg/m3 | 0.3mg/m3 |
Tin metal and oxide | 2mg/m3 | 4mg/m3 |
Titanium dioxide | 10mg/m3 | 20mg/m3 |
Vanadium pentoxide, respirable** | 0.05mg/m3 | 0.15mg/m3 |
Zinc oxide, respirable** | 2mg/m3 | 10mg/m3 |
** For respirable fraction, see Table B of Schedule O
CL | TWA | STEL | C |
Argon* | None | None | None |
Carbon Dioxide | 5,000ppm | 30,000ppm | None |
Carbon Monoxide | 25ppm | 190ppm | None |
Helium* | None | None | None |
Hydrogen Fluoride | 0.5ppm | None | 2ppm |
Nitric Oxide | 25ppm | 38ppm | None |
Nitrogen* | None | None | None |
Nitrogen Dioxide | 3ppm | 5ppm | None |
Ozone | 0.05ppm | 0.15ppm | None |
Phosgene | 0.1ppm | 0.3ppm | None |
Ontario Regulation 833, Control of Exposure to Biological or Chemical Agents – Welding Fume
In Ontario, employers are required under section 4 of Regulation 833, Control of Exposure to Biological or Chemical Agents, to limit the exposure of workers to specified 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.”
Regulation 833 also stipulates that: “An employer shall protect workers from exposure to a hazardous biological or chemical agent without requiring them to wear and use a respirator.” Which means that welding fume extractors should be used to extract pollutants at the source.
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 |
Any questions? Ask them directly in the chat at the bottom right of your screen or during one of our webinars.

Prince Edward Island Workplace Health and Safety Regulations – Welding Fume
In Prince Edward Island, companies must follow Occupational Health and Safety Act General Regulations. Welding regulations can be found in Part 37 (Welding), and Threshold Limit Values (TLV) are defined in Part 11 (Ventilation). Here is some information to know.
37.1 Ventilation
“Where welding or cutting or soldering operations emit harmful fumes and gases, the employer shall ensure that ventilation is provided which will remove the fumes at the source required to maintain the airborne contaminants at or below the permissible levels as outlined in Part 11 of these regulations.”
11.3 Threshold limit values
” Where the air of working areas is contaminated by vapors, fumes, gases, mists or other impurities which constitute a hazard to the health or safety of workers, suitable means of ventilation shall be provided by the employer to reduce contamination in the atmosphere at or below the threshold limit values specified by the American Conference of Governmental Industrial Hygienists (ACGIH) in the 2019 edition of the publication “Threshold Limit Values and Biological Exposure Indices”, as amended from time to time.”
You can find links to the ACGIH Threshold Limit Values at the end of this article.
Quebec Regulation Respecting Occupational Health and Safety – Welding Fume
In Quebec, companies must follow the Regulation respecting occupational health and safety. Permissible Exposure Values (PEV) for gases, dust, fumes, vapors, or mists in the work environment can be found in Schedule I. Chapter 107 stipulates that local exhaust ventilation is required for welding.
“Local ventilation: Any localized source at a stationary workstation that emits dusts, gases, fumes, vapours or mists shall be equipped with a local exhaust ventilation system for trapping the dusts, gases, fumes, vapours or mists at their source.”
Division V introduces the permissible exposure value table: “No worker in an establishment shall be exposed to a concentration of airborne oxygen below 19.5% in volume at normal atmospheric pressure; gases, fumes, vapours, dusts or mists, beyond the limits provided for in Schedule I.”
Finally, there is an important note in Schedule I.
“EXCURSION LIMITS: These limits apply to substances which do not have a short-term exposure value. Provided the time-weighted average exposure value is not exceeded, excursions in exposure levels may exceed 3 times that value for a cumulative period not exceeding a total of 30 minutes during a workday. Notwithstanding the foregoing, none of those excursions in exposure levels may exceed 5 times the time-weighted average exposure value during any length of time whatsoever.”
PEV | TWAEV | STEV |
Welding Fumes | 5mg/m3 | None |
PEV | TWAEV | STEV |
Aluminum | 5mg/m3(r) | None |
Antimony | 0.5mg/m3 | None |
Arsenic* | 0.01mg/m3 | None |
Beryllium* | 0.15µg/m3 | None |
Cadmium | 0.01 mg/m3 | None |
Chromium metal & (III) | 0.5mg/m3 | None |
Chromium (VI)* | 0.001mg/m3 | None |
Cobalt | 0.02mg/m3(i) | None |
Copper | 0.2mg/m3 | None |
Iron Oxide | 5mg/m3 | None |
Lead | 0.05mg/m3 | None |
Manganese | 0.2mg/m3(i) 0.05mg/m3(r) | None |
Molybdenum | 3mg/m3(r) 10mg/m3(i) | None |
Nickel | 1.5mg/m3(i) | None |
Silver | 0.1mg/m3 | None |
Tin metal & oxide | 2mg/m3(i) | None |
Titanium dioxide | 10mg/m3(t) | None |
Vanadium pentoxide | 0.05mg/m3(i) | None |
Zinc oxide | 2mg/m3(r) | 10mg/m3(r) |
PEV | TWAEV | STEV | C |
Argon* | None | None | None |
Carbon Dioxide | 5,000ppm | 30,000ppm | None |
Carbon Monoxide | 35ppm | 200ppm | None |
Helium* | None | None | None |
Hydrogen Fluoride** | None | None | 3ppm |
Nitric Oxide | 25ppm | None | None |
Nitrogen* | None | None | None |
Nitrogen Dioxide | 3ppm | None | None |
Ozone** | None | None | 0.1ppm |
Phosgene | 0.1ppm | None | None |
** Cannot be recirculated

Saskatchewan Occupational Health and Safety Regulations – Welding Fume
In Saskatchewan, companies must follow the Occupational Health and Safety Regulations. Contamination limits can be found in Table 18, as explained in Section 21.6.
“If a chemical substance or biological substance listed in Table 18 of the Appendix is present at a place of employment, an employer shall: provide adequate engineering controls, to the extent that it is reasonably practicable to do so, to ensure that the contamination limit set out in Table 18 is not exceeded in any area where a worker is usually present; and take all practicable steps to ensure that no worker’s personal exposure exceeds the contamination limit set out in Table 18.”
Sections 6.2 and 6.3 detail the expectations regarding ventilation. Here are a few quotes that could apply to welding fume. As you will see, companies are encouraged to use welding fume extractors.
“(1) An employer, contractor or owner shall provide a mechanical ventilation system in a place of employment that is sufficient and suitable to protect the workers against inhalation of a contaminant and to prevent accumulation of the contaminant and ensure that the mechanical ventilation system is maintained and properly used, if any work, activity or process in the place of employment gives off a dust, fume, gas, mist, aerosol or vapour or other contaminant of a kind and quantity that is likely to be hazardous to workers; or substantial quantities of contaminants of any kind.”
“(3) If practicable, an employer, contractor or owner shall ensure that a mechanical ventilation system required by subsection (1) includes local exhaust ventilation that is installed and maintained at or near the point of origin of the contaminant so as to prevent effectively the contaminant from entering the air of the place of employment […]”.
CL | TWA | STEL |
Welding Fumes | 5mg/m3 | 10mg/m3 |
OEL | TWA | STEL |
Aluminum oxide | 10mg/m3 | 20mg/m3 |
Antimony | 0.5mg/m3 | 1.5mg/m3 |
Arsenic | 0.01mg/m3 | 0.03mg/m3 |
Beryllium | 2µg/m3 | 0.01mg/m3 |
Cadmium | 0.01mg/m3(t) 2µg/m3(r) | 0.03mg/m3(t) 6µg/m3(r) |
Chromium metal & (III) | 0.5mg/m3 | 1.5mg/m3 |
Chromium (VI), soluble | 0.05mg/m3 | 0.15mg/m3 |
Chromium (VI), insoluble | 0.01mg/m3 | 0.03mg/m3 |
Cobalt | 0.02mg/m3 | 0.06mg/m3 |
Copper fume | 0.2mg/m3 | 0.6mg/m3 |
Iron Oxide | 5mg/m3 | 10mg/m3 |
Lead | 0.05mg/m3 | 0.15mg/m3 |
Manganese | 0.2mg/m3 | 0.6mg/m3 |
Molybdenum | 3mg/m3(r) 10mg/m3(i) | 6mg/m3(r) 20mg/m3(i) |
Nickel | 1.5mg/m3(i) | 3mg/m3(i) |
Silver | 0.1mg/m3 | 0.3mg/m3 |
Tin metal & oxide | 2mg/m3 | 4mg/m3 |
Titanium dioxide | 10mg/m3 | 20mg/m3 |
Vanadium pentoxide | 0.05mg/m3(r) | 0.15mg/m3(r) |
Zinc oxide | 2mg/m3(r) | 10mg/m3(r) |
OEL | TWA | STEL | C |
Argon* | None | None | None |
Carbon Dioxide | 5,000ppm | 30,000ppm | None |
Carbon Monoxide | 25ppm | 190ppm | None |
Helium* | None | None | None |
Hydrogen Fluoride | 0.5ppm | None | 2ppm |
Nitric Oxide | 25ppm | 38ppm | None |
Nitrogen* | None | None | None |
Nitrogen Dioxide | 3ppm | 5ppm | None |
Ozone | 0.05ppm | 0.15ppm | None |
Phosgene | 0.1ppm | 0.3ppm | None |
Yukon Workers’ Safety and Compensation Act – Welding Fume
In Yukon, employers must comply with the Workers’ Safety and Compensation Act, which is a consolidation of multiple regulations.
Welding regulations can be found in Part 13 (Trades and Miscellaneous), article 13.08 to 13.12 of the Occupational Health and Safety Regulations. Here are a few essential parts.
“Any fixed workplace shall have effective local exhaust ventilation to minimize worker exposure to harmful air contaminants produced by welding, burning or soldering.”
“Work areas close to welding, cutting, burning or soldering shall be monitored to ensure that the concentration of the air contaminants is kept within the limits, as established by the Occupational Health Regulations.”
“Respiratory protective equipment shall be used only for short duration welding or burning operations if the use of effective local exhaust ventilation is not practicable.”
Finally, Permissible Concentrations for Airborne Contaminant Substances can be found in Table 8 of the Occupational Health Regulations.
PCACS | TWA | STEL |
Welding Fumes | 5mg/m3 | 5mg/m3 |
PCACS | TWA | STEL |
Aluminum | None | None |
Antimony | 0.5mg/m3 | 0.75mg/m3 |
Arsenic | 0.5mg/m3 | 0.5mg/m3 |
Beryllium | 2µg/m3 | None |
Cadmium | 0.05mg/m3 | None |
Chromium | None | None |
Cobalt | 0.05mg/m3 | 0.15mg/m3 |
Copper | 0.2mg/m3 | 0.2mg/m3 |
Iron Oxide | 5mg/m3 | 10mg/m3 |
Lead | 0.15mg/m3 | 0.45mg/m3 |
Manganese | 5mg/m3 | None |
Molybdenum | 5mg/m3 | 10mg/m3 |
Nickel | 1mg/m3 | 3mg/m3 |
Silver | 0.01mg/m3 | 0.03mg/m3 |
Tin oxide | 10mg/m3 | 20mg/m3 |
Titanium dioxide | 10mg/m3 | 20mg/m3 |
Vanadium | 0.05mg/m3 | None |
Zinc oxide | 5mg/m3 | 10mg/m3 |
PCACS | TWA | STEL |
Argon* | None | None |
Carbon Dioxide | 5,000ppm | 15,000ppm |
Carbon Monoxide | 50ppm | 400ppm |
Helium* | None | None |
Hydrogen Fluoride | 3ppm | 3ppm |
Nitric Oxide | 25ppm | 35ppm |
Nitrogen* | None | None |
Nitrogen Dioxide | 5ppm | None |
Ozone | 0.1ppm | 0.3ppm |
Phosgene | 0.1ppm | 0.3ppm |
ACGIH Threshold Limit Values for Welding Fume
Threshold Limit Values (TLV) 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. Use them to know the OELs to follow.
ACGIH has not published a recommendation regarding welding fumes in general. Therefore, they fall under the Particulates Not Otherwise Regulated category. The ACGIH recommendation, in this case, 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, 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.

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