Welding fumes are toxic and carcinogenic. Therefore, protecting welders and their colleagues is very important. We have been involved in the welding industry for over 40 years, and this is the step-by-step method we have developed to solve welding fume problems and prevent workers from inhaling hazardous particles and gases.
As you will see, steps 1 to 7 should consistently be implemented (unless impossible), but step 8 should only be considered if the welding fume problem is not solved yet. Furthermore, steps 1 to 4 are meant to reduce the fume to a minimum, while steps 5 to 8 are all about protecting welders.
If you need help or have questions, feel free to contact us.
1 – Only weld when it is necessary.
This first step, although very important, is not always feasible. But companies should consider alternatives to manual welding.
Robotic welding is more affordable than ever. Some welding robots can be efficient even in manufacturing small batches. It is not a luxury that only big companies can afford and is worth exploring, especially nowadays since welders are hard to find. Moreover, extracting fume generated by a welding robot is a lot easier as the goal is to protect workers around instead of welders close to the welding pool.
Other processes can sometimes replace welding, like mechanical fastening (bolts, screws, rivets, etc.) or adhesive bonding (there are multiple metal-to-metal adhesives available on the market). You will have to make sure that the properties offered by the alternative joining method are adequate for your needs.
2 – Isolate welding operations from other workers
The second step will not protect welders per se but will prevent other workers around from breathing toxic welding fume.
Some companies ensure that all welding operations are performed in one building, room, or area. Ideally, it could be a place where only welders are working. But more realistically, it is at least possible to limit the number of workers around welding operations.
If people are working close to welders, it is always better to use welding screens. They will protect them from bright arcs, sparks, and ultraviolet radiation. Welding curtains hanging from the ceiling are even better since they can also contain fumes that can easily be extracted.
3 – Use welding processes that produce less fume
Although it is only one variable of the equation, some welding processes produce less fume than others. However, that does not mean that they do not require local exhaust ventilation to be within the permissible exposure limits, nor are they necessarily less dangerous.
But everything else being equal, it is interesting to know which welding and cutting process to favor if you have the possibility to choose:
- Less fume: TIG, resistance welding, submerged arc, laser cutting
- More fume: MIG, MAG, plasma cutting
- The most: Stick welding, flux cored, arc gouging
You could also experiment and change the power settings to reduce fumes. An American research article called Evaluation of operational parameters role on the emission of fumes concluded that: “For reducing exposures to fumes, welders are recommended to use the lowest voltage and amperage and the highest travel speed to the extent that does not compromise in the quality of welds.”
A research institute in Canada also published a detailed resource called Influence of Electric Arc Welding Parameters on Fume Concentrations and Their Metal Constituents: State of Knowledge. Here are some of their conclusions:
- “GMAW using the pulsed […] mode generates less manganese and hexavalent chromium fumes than the conventional GMAW process.”
- “An increase in the carbon dioxide fraction in a shielding gas mixture causes a corresponding increase in the quantity of fumes.”
- “An increase in voltage, current strength or electrode diameter also leads to higher fume levels.”
- “The same thing occurs when more flux is used, in the electrode core (FCAW) or coating (SMAW).”
- “For GMAW, pulsed spray transfer is associated with lower fume levels than the short-circuit and axial spray transfer modes.”
4 – Use consumables and materials that produce less toxic fume
The first thing to know is that you should never weld metal covered with plating, paint, primer, solvent, lubricant, oils, rust inhibitors, or any other type of coating. They will always add to the quantity and toxicity of the welding fume, sometimes drastically.
You should remove them from welding areas, which will likely improve the weld quality as well. Always follow the appropriate safety procedures during the removal process. Contact your supplier for more information on the products and ways to remove them safely.
Grinding coatings could seem like a good idea and an easy solution, but it is essential to know that grinding dust could also be toxic and create another problem instead of solving one.
The next thing to do is to avoid, or at least reduce, the quantity of carcinogenic and toxic substances in the materials and consumables used. Here is a list of metals and gases that are particularly problematic:
- Toxic: lead, manganese, cadmium, ozone
- Carcinogenic: hexavalent chromium, cadmium, beryllium, nickel
- Metal fume fever: zinc, copper, magnesium, aluminum, cadmium, iron oxide, manganese, nickel, selenium, silver, tin
We understand that it is virtually impossible to avoid all of these, but many solutions are available to reduce their concentration.
In the first four steps, you should have done everything you can to reduce the quantity and toxicity of welding fume to a minimum. Now we must ensure workers do not breathe the remaining smoke.
5 – Use welding fume extractors
It is time to remove the welding fume with local exhaust ventilation (or source extraction). As a rule of thumb, the closer you can extract it from the weld pool, the more efficient it will be, and the better welders will be protected. There are five leading welding fume extraction technologies:
- Fume extraction MIG guns
- Fume extraction arms
- Fume extraction nozzles
- Fume extraction hoods
- Downdraft tables
The following table introduces the best ways to extract welding fume depending on the process used.
|MIG / GMAW||Best||Yes||Yes||No||No|
|TIG / GTAW||No||Best||Yes||No||No|
|Fluxed-Cored / FCAW||Best||Yes||Yes||No||No|
|Stick / SMAW||No||Best||Yes||No||No|
For more information on selecting the proper extractors and which performances are necessary, read the article about welding fume extractors or MIG welding fume extraction if that’s the process you are using. You can also check our resource helping you choosing between a portable or stationary vacuum unit.
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.
6 – Make sure welders position themselves to avoid breathing fumes and gases
Step 6 is simple. Welders should take advantage of the elements and their environment to avoid breathing welding fume. For example, they can use the wind or air circulation to drive the welding fume away from them.
In general, welders should avoid placing their heads just above the welding pool since the welding fume naturally climbs.
Finally, they should never place their head between the weld pool and the fume extractor. Otherwise, the extractor does not protect them since they still have fumes in their face. And it also reduces its efficiency, meaning the smoke could travel elsewhere in the factory and incommode other workers (not a problem with fume extraction MIG guns since the smoke is extracted a few inches away from the weld).
7 – Make sure your factory is adequately ventilated
Ambient ventilation should be used in addition to source extraction, not as a replacement.
According to OSHA: “General mechanical ventilation shall be of sufficient capacity and so arranged as to produce the number of air changes necessary to maintain welding fumes and smoke within safe limits.” In practice, an air exchange rate between four and 12 is usually appropriate (it includes the air extracted by fume extractors as well).
It depends on the quantity and toxicity of the fumes produced and on the efficiency of the source extraction systems. They can significantly reduce the required air exchange rate. Therefore, the general ventilation system can be smaller and cheaper and it generates considerable savings in heating and air conditioning.
According to the AIHA (American Industrial Hygiene Association), in a confined space, an acceptable practice is 20 air changes per hour.
8 – Use personal protective equipment
At this point, the welding fume problem should be solved, and permissible exposure limits should be met at every workstation. If that is not the case, personal protective equipment, such as masks and respirators, must be used. They have to be fitted for each worker individually.
But this has to be the last resort. Health and safety agencies require employers to take every other measure before using PPEs to solve welding fume problems. Therefore, masks or respirators should not be permanently necessary for welding operations; if required, they should only be for short periods.
I will recommend this 3M guide to learn more about respiratory protective equipment for welders if it comes to that.
How much welding fumes can you breathe in before it becomes harmful?
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:
- Welding Fume Regulations and Exposure Limits in the US
- Welding Fume Regulations and Exposure Limits in California
- Welding Fume Regulations and Exposure Limits in Canada
In these articles, you will also find recommendations from the American Conference of Governmental Industrial Hygienists (ACGIH). These concentrations are considered safe nowadays if the welder does not work more than 8 hours a day and welds in a typical environment.
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. 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, which requires keeping it as low as reasonably possible.
Many hazardous substances found in welding fumes are also subjected to their exposure limit, such as chromium, manganese, etc.
Health issues caused by toxic 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
- Chest pain
- 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
- Different types of cancer
Feel free to contact us. We will help you protect your workers and comply with welding fumes standards anywhere in the US and Canada.