What is Welding Fumes?- Hazards, And How to Reduce It

Welding is the process of joining materials together using a molten metal workpiece, along with a filler metal, creating a strong joint. The process of welding creates visible smoke that contains harmful metal fumes and gas by-products.

This fact sheet identifies the welding operations, standards that will apply, and guidance to protect welders and their co-workers from the exposure to the various hazardous substances contained in welding fumes.

What are welding fumes?

Welding fumes are a complex combination of metallic oxides, silicates and fluorides. Fumes are formed when a metal is heated above its boiling point, the vapors of the metal condense into fine, solid particles (etc. For welding, a fume is made up of a collection of particles from the electrode and the metal.

Welding fume is an inconsistent mixture of airborne gases and fine particles. The mixture will vary based on the welding process, and the products being welded. Gases that may be released include for example:

• Shielding: Argon, Helium, Nitrogen, Carbon Dioxide.
• Process: Nitric Oxide, Nitrogen Dioxide, Carbon Monoxide, Ozone, Phosgene, Hydrogen Fluoride, Carbon Dioxide.

Additionally, it may contain a lot of fine metallic oxides solids or particulates and/or fluorides and/or metals including Aluminum, Antimony, Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Copper, Iron, Lead, Manganese, Nickel, Molybdenum, Silver, Tin, Titanium, Vanadium, and Zinc.

Factors that affect worker exposure to welding fume

• Type of welding process
• Base metal and filler metals used
• Welding rod composition
• Location (outside, enclosed space)
• Welder work practices
• Air movement
• Use of ventilation controls

Three factors determine the risks

The level of the risk, if no adjuvant ventilation and protective measures are taken, depends on three factors:

• The Toxicity of The Fume
• The Concentration of The Fume
• For How Long the Fume Has Been Inhaled.

1. Toxicity of the welding fume

The chemical composition and effectiveness from the fume varies widely. As stated, it depends on the type of welding process, the welding materials, and also the type of metal being welded.

We will write more about fumes from mild steel welding, stainless steel welding, also from welding of coated metals, and also fumes of welding specific products and processes.

2. Concentration of the welding fume

The concentration of the fume and the harmful substances are the highest in the plume of fume that rises from the welding point. The faster this fume is eliminated by ventilation, the better.

3. Duration of inhaling welding fumes

A welder’s exposure to fume is based simply upon the duration of the welding. Some fabricators only weld one or two hours a day, while others can weld all day.

A straightforward calculation, (also referred to as the arcing time), apply to welding. The longer you weld, the more fume, and the greater risk of inhaling the airborne gases and fine particles created.

Welding fumes can cause serious diseases

It is quite apparent that inhaling welding fume is possibly hazardous. For those that are not convinced, just read the countless scientific studies and reports explaining how welding fume can create all types of physical complaints and serious diseases such as cancer, asthma, and even symptoms of Parkinson’s disease.

Health effects of breathing welding fume

• Acute exposure to welding fumes and gases can lead to eye, nose, and throat irritation, headaches, dizziness, and nausea. Workers present in the area displaying these symptoms should leave the area immediately for fresh air and seek medical attention.
• Chronic exposure to welding fume may cause lung damage and multiple cancers, including lung cancer, laryngeal cancer, and urinary tract cancer.
• Health symptoms related to certain fumes may include metal fume fever, stomach ulcers, kidney damage, and damage to the nervous system. Chronic exposure to manganese fume can produce Parkinson’s-like symptoms.
• Gases of helium, argon, and carbon dioxide can displace oxygen in air leading to the possibility of asphyxiation or suffocation, especially in confined or enclosed spaces. Carbon monoxide gas can even be formed and present a severe asphyxiation hazard.

Source and Health Effect of Welding Fumes

Fume Type	Source	Health Effect
Aluminum	Aluminum components of some alloys, e.g., Inconel, copper, zinc, steel, magnesium, brass, and filler materials.	Respiratory irritant.
Beryllium	Hardening agents are found in copper, magnesium, aluminum alloys, and electrical contacts.	“Metal Fume Fever.” A carcinogen. Other chronic effects include damage to the respiratory tract.
Cadmium Oxides	Stainless steel containing cadmium or plated materials, zinc alloy.	Irritation of respiratory system, sore and dry throat, chest pain, and breathing difficulty. Chronic effects include kidney damage and emphysema. Suspected carcinogen.
Chromium	Most stainless-steel and high-alloy materials, welding rods. Also used as the plating material.	Increased risk of lung cancer. Some individuals may develop skin irritation. Some forms are carcinogens (hexavalent chromium).
Copper	Alloys such as Monel, brass, bronze. Also some welding rods.	Acute effects include irritation of the eyes, nose, and throat, nausea, and “Metal Fume Fever.”
Fluorides	Common electrode coating and flux material for both low- and high-alloy sheets of steel.	The acute effect is irritation of the eyes, nose, and throat. Long-term exposures may result in bone and joint problems. Chronic effects also include excess fluid in the lungs.
Iron Oxides	The major contaminant in all iron or steel welding processes.	Siderosis – a benign form of lung disease caused by particles deposited in the lungs. Acute symptoms include irritation of the nose and lungs. Tends to clear up when exposure stops.
Lead	Solder, brass, and bronze alloys, primer/coating on steels.	Chronic effects to the nervous system, kidneys, digestive system, and mental capacity. Can cause lead poisoning.
Manganese	Most welding processes, especially high-tensile steels.	“Metal Fume Fever.” Chronic effects may include central nervous system problems.
Molybdenum	Steel alloys, iron, stainless steel, nickel alloys.	Acute effects are eye, nose, and throat irritation, and shortness of breath.
Nickel	Stainless steel, Inconel, Monel, Hastelloy, and other high-alloy materials, welding rods, and plated steel.	The acute effect is irritation of the eyes, nose, and throat. Increased cancer risk has been noted in occupations other than welding. Also associated with dermatitis and lung problems.
Vanadium	Some steel alloys, iron, stainless steel, nickel alloys.	The acute effect is irritation of the eyes, skin, and respiratory tract. Chronic effects include bronchitis, retinitis, fluid in the lungs, and pneumonia.
Zinc	Galvanized and painted metal.	Metal Fume Fever.

Source and Health Effect of Welding Gases

Gas Type	Source	Health Effect
Carbon Monoxide	Formed in the arc.	Absorbed readily into the bloodstream, causing headaches, dizziness, or muscular weakness. High concentrations may result in unconsciousness and death
Hydrogen Fluoride	Decomposition of rod coatings.	Irritating to the eyes and respiratory tract. Overexposure can cause lung, kidney, bone, and liver damage. Chronic exposure can result in chronic irritation of the nose, throat, and bronchi.
Nitrogen Oxides	Formed in the arc.	Eye, nose, and throat irritation in low concentrations. Abnormal fluid in the lung and other serious effects at higher concentrations. Chronic effects include lung problems such as emphysema.
Oxygen Deficiency	Welding in confined spaces, and air displacement by the shielding gas.	Dizziness, mental confusion, asphyxiation, and death.
Ozone	Formed in the welding arc, especially during plasma-arc, MIG, and TIG processes.	Acute effects include fluid in the lungs and hemorrhaging. Very low concentrations (e.g., one part per million) cause headaches and dryness of the eyes. Chronic effects include significant changes in lung function.

Source and Health Effect of Organic Vapors as a result of Welding

Gas Type	Source	Health Effect
Aldehydes (such as formaldehyde)	Metal coating with binders and pigments. Degreasing solvents	Irritant to eyes and respiratory tract.
Diisocyanates	Metal with polyurethane paint.	Eye, nose, and throat irritation. High possibility of sensitization, producing asthmatic or other allergic symptoms, even at very low exposures.
Phosgene	Metal with residual degreasing solvents. (Phosgene is formed by the reaction of the solvent and welding radiation.)	Severe irritant to eyes, nose, and respiratory system. Symptoms may be delayed.
Phosphine	Metal coated with rust inhibitors. (Phosphine is formed by the reaction of the rust inhibitor with welding radiation.)	Irritant to the eyes and respiratory system can damage kidneys and other organs.

Reducing exposure to welding fume

• Welders should know the hazards associated with the materials they are using. OSHA’s Hazard Communication standard requires employers to provide training and information to workers about the hazards of materials used in the workplace.
• Welding surfaces should be cleaned of any coating that may have resulted in potentially toxic exposure; this includes all residues from solvents and coatings like paint.
• Workers should consider the position of themselves relative to welding fume and gases. For example, when working outdoors or in an open-air environment, workers should remain upwind.
• Ventilation, which is the natural or forced movement of air, can help lower the levels of fumes and gases present in the work area. Working outdoors or in an open situation does not equate to adequate ventilation. In the absence of a ventilation and exhaust system, welders will need to make use of natural drafts, and proper positioning to help keep fumes and gases away from themselves and other workers.
• Local exhaust ventilation systems can help remove fumes and gases from the welder’s breathing zone. Positioning fume hoods or fume extractor guns; and keeping vacuum nozzles close to the source of the plume, can help remove the maximum amount of fumes and gases. Portable exhaust systems or other flexible systems should be positioned to draw fumes and gases away from workers heating and welding, while keeping exhaust vent ports away from other workers.
• Explore different welding types or consumables that are less toxic or generate less fumes.
• Do not weld in a confined space without ventilation. See appropriate OSHA regulations.
• Respirators may be required when work practices and ventilation do not reduce exposures to safe levels.

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