How to Stay Safe from Welding Fumes and Gases
PPE may be essential for keeping welders safe, but it should be treated as the last line of defense against respiratory hazards.
Open flames, sparks, and high heat may be some of the most visible hazards in the welding process, but welding also comes with respiratory hazards that need to be taken seriously.
These hazards fall broadly into three categories:
- Welding fumes that are created when the metal's temperature is raised above its boiling point (welding fume particles are smaller than regular dust particles by a degree of magnitude)
- Welding vapors that occur when the electrode and the material being welded coalesce into very fine, solid particles that are easily inhaled
- Welding gases that are either used in the welding or cutting process, produced by the decomposition of fluxes, or by the reaction between UV radiation and gases or vapors in the atmosphere (organic vapors can also result from these reactions)
The exact nature of each of these will depend on the type of welding that produces them, the material being welded, the electrode used, as well as any coating or residue present on the welded material.
Although we're discussing different substances, they all have one thing in common. All welding fumes, gases, and organic vapors pose a risk to the welder and anyone else in the vicinity of the welding activity. Exposure can affect the skin, eyes, central nervous system, kidneys, bones, joints, and respiratory tract. The severity of the resulting condition ranges from mild irritation to various types of cancer.
It is imperative, then, that all welding is done with the appropriate precautions in place. In this article, we'll go over what it takes to protect against these respiratory hazards.
(Learn more in What You Need to Know About Welding Apparel)
Protecting Against Welding Fumes, Gases, and Organic Vapors
Opening the overhead doors in the shop can provide some amount of ventilation. While this can certainly help, it's not always enough to move or dilute welding fumes and gases below hazardous levels.
Those hazardous levels are most commonly based on the Permissible Exposure Limit (PEL) established by OSHA and the Threshold Limit Values (TLV) established by the American Conference of Governmental Industrial Hygienists (ACGIH). To use these measures, however, you must be able to take samples of the air in the welder's breathing zone to ensure that the sample has a value below the stated PEL or TLV.
This simple natural ventilation method also has serious limitations due to the variety of materials that are used throughout the work cycle, variations of the air influx, and the welder changing positions to get a better view of the work area. More control methods will almost certainly be required.
As with all health and safety hazards, the right approach to managing these risks is to follow the hierarchy of hazard controls. It is always best to implement higher-level controls instead of opting strictly for protective gear.
To give you a better sense of what a comprehensive control strategy would look like, let's go through each type of hazard control and see how they can be used to reduce the respiratory risks associated with welding.
Elimination is the highest and most desirable level of control. However, it often can't be applied due to the diversity of tasks needed to get a job done. Field welding work and repairs fall under this category.
It is often feasible in mass production, however. Automatic welding robots have already been put to work producing screw piles, welding vehicle chassis, and many things in between. Some of these automatic welders are fully autonomous, while others require human interaction to get started on a new piece or be refilled with consumables.
Even in the latter case, robotic welding reduces the amount of time workers have to spend around welding fumes and gases. Not only are fewer workers needed to complete the welding process, but those who are involved can stay further away when the welding is carried out.
When welding tasks can't be eliminated, it is sometimes possible to substitute one welding product for another that produces fewer fumes or gases.
Some substitution options include:
- Switching from shielded metal arc welding (SMAW) to gas metal arc welding
(GMAW), eliminating the flux that generates gases by decomposition
- Using low manganese filler metal or manganese-free welding rods to decrease the risk of
central nervous system problems and “Metal Fume Fever”
- Using processes that generate fewer gases or fumes, such as cold joining
- Rethinking the design of a piece so that it requires fewer welded parts, possibly by connecting some of the parts with bolts instead of welding them together
- Using water-based cleaners or high flashpoint solvents to clean welding material
- Using uncoated materials or removing the coating before welding to decrease the fumes
Engineering controls generally gravitate around ventilation, which helps control how welding fumes move. This can be achieved by natural ventilation (e.g., working outdoors, opening the shop door), mechanical ventilation at the source, or local capture devices such as fume extractors. All of these will keep the welding fumes and gases away from the welder’s breathing zone, avoiding inhalation.
Another engineering control is isolation, which physically isolates welding tasks from the other activities in the shop. While this does not provide additional protection to the welders, it reduces the number of employees who are exposed to the fumes and gases produced by them.
(To learn more, check out A Primer on Engineering Controls)
The key element is positioning to avoid intersecting the breathing zone with the plumes of welding fumes. To achieve this, the worker can:
- Reposition their head or body so they are not in the way of the fumes (this can generally be achieved by positioning themselves to the side of the weld instead of above it)
- Reposition their body or work piece so the airflow is from the back to front, thus moving the gases and fumes away from the welder
The safe work procedure should take this into consideration and ensure that the task is designed such that completing the task is compatible with the proper body positioning.
Other administrative controls that can minimize exposure to welding fumes and gases include:
- Developing and implementing an exposure plan for welding fumes and gases
- Installing warning signs (to warn non-welding personnel not to enter the area or reminder welders to practice proper positioning, for example)
- Changing the work schedule to ensure that there are no non-welding personnel working in areas where welding is in progress
Personal Protective Equipment
When these higher level controls can’t keep the exposure levels below the PEL or TVL, welders will have
to wear adequate personal protective equipment (PPE).
The most common PPE for fumes and gases are NIOSH-approved respirators. Since welding tasks have many variables, it is important to ensure the use of gas cartridges that are specific to the task. Clause 4.5 of ANSI standard Z49.1:2021 provides directions regarding respiratory protective equipment for welders.
Companies resorting to the use of PPE to protect against welding fumes and gases should have a respiratory protection program in place. That program should include, among other things, fit testing to ensure that each welder's mask works effectively.
In areas with high levels of fumes and gases, using powered air-purifying respirators (PAPRs) can improve the comfort of the welders. Among other advantages, PAPRs provide the user with cool air, which is a welcome relief for welders who have to wear heavy PPE or work in hot shops.
(Find out How to Complete a Respirator Fit Test)
Employers have an obligation to protect employees from known hazards. In the case of welders, this includes the fumes and gases that are a major and constant concern.
As we've seen in this article, protecting these workers can take many forms. Ideally, those will include higher level hazard controls, with PPE as a last resort used in combination with other control methods.
And remember, while the welders themselves are most obviously at risk, the fumes and gases produced by their work disperse easily. This means that non-welding personnel working nearby are also at risk and need to be protected as well.