Are welding fumes toxic & what are OSHA’s recommendations for welding fumes safety?

Are welding fumes toxic?

Fumes generated due to welding affect the lungs. They are toxic in some cases and carcinogenic even when welding mild steel as per 2020 study by OHSAS. The health consequences for the welder depend mostly on the composition of welding fumes & type of material to be welded.

The hazardous matters in welding fumes formed during welding are depends on several components:

  1. Basic and supplementary materials,
  2. inert gases, coatings,
  3. contamination and ambient air.

The type and quantity of the hazardous substances in welding fumes depend on the welding process and the materials used. Their effect can be divided into three categories:

  • Respiratory and lung-damaging substances
  • Toxic (poisonous) hazardous substances
  • Carcinogen (carcinogenic) hazardous substances
Welding fumes generation

How welding fumes damage lungs and respiratory system?

If welders are exposed to a high concentration of these hazardous substances in welding fumes over a longer period, then this may lead to a strain on the respiratory system, specifically the lungs. Respiratory diseases such as bronchitis up to a permanent narrowing of the respiratory system (obstructive bronchitis) are the consequence.

Furthermore, dust deposits can settle in the lungs. These may occur in the form siderosis (iron overload) when working with iron oxides. The absorption of high concentrations of hazardous substances in welding fumes also triggers fibro-genic reactions (connective tissue proliferation) in the lungs. Substances affecting the lungs and their effect on the human body are e.g.:

  • Iron oxides: Dust deposits in the lung (welders’ lung or lung siderosis) / Siderosis (leads to joint problems, diabetes, congestive heart failure or impotence)
  • Aluminum oxide: Aluminosis (aluminum dust lung, causes a change of the functional lung tissue into non-functional tissue)
  • Magnesium oxide: Fever, sweats, tickle in the throat / Irritation of the eyes and nasal mucosa / Impaired lung function
  • Titanium dioxide: Dust deposits in the lungs / Damage of liver, spleen, kidneys, heart and brain / Weakening of the immune system

Health effects of breathing welding fume

  • Acute exposure to welding fume and gases can result in eye, nose and throat irritation, dizziness and nausea. Workers in the area who experience these symptoms should leave the area immediately, seek fresh air and obtain medical attention.
  • Prolonged exposure to welding fume may cause lung damage and various types of cancer, including lung, larynx, and urinary tract.
  • Health effects from certain fumes may include metal fume fever, stomach ulcers, kidney damage and nervous system damage. Prolonged exposure to manganese fume can cause Parkinson’s–like symptoms.
  • Gases such as helium, argon, and carbon dioxide displace oxygen in the air and can lead to suffocation, particularly when welding in confined or enclosed spaces. Carbon monoxide gas can form, posing a serious asphyxiation hazard.

Poisonous hazardous substances in welding fumes can be fatal (Metals in Welding fumes)…

Toxic (poisonous) hazardous substances in welding fumes have a toxic effect in the body once a certain concentration is reached. The concentration is decisive with regards to the effect: Whilst slight poisoning may lead to minor health problems, large concentrations of these hazardous substances in welding fumes may cause life-threatening poisoning or at worst be fatal. Depending on hazardous substances, the dangerous dose varies according to the hazardous substances. The toxic hazardous substances in welding fumes include:

  • Manganese oxide: Irritant effect on the respiratory system /Pneumonia / Damages of the nervous system / Parkinson’s disease
  • Zinc oxide: Zinc fever (nanoparticles in the lungs lead to cell necrosis)
  • Copper oxide: Nausea, diarrhea, pain in the eyes / Metal fume fever (malaise with symptoms similar to having the chills) / Damage of liver and kidneys
  • Nitrogen oxides:  Irritation of the respiratory system and shortness of breath / Potentially fatal pulmonary oedema (lung dropsy)
  • Carbon monoxide: Prevents the oxygenation of blood and thus leads to an undersupply of organs / Dizziness, fatigue, headaches, fainting, pulse and breathing increase in pulse rate and quicker breathing / Unconsciousness, respiratory paralysis, cardiac arrest
  • Carbon dioxide: Increased respiratory rate and volume / Dizziness, headache, shortness of breath and unconsciousness
  • Phosgene: Severe respiratory system irritation / Pulmonary oedema

Further toxic hazardous substances in welding fumes are soluble barium compounds, calcium oxide, fluorides, and vanadium pentoxide.

Main danger: carcinogenic hazardous substances in welding fumes

Carcinogenic hazardous substances in all types of welding fumes can cause severe tumors in the body. Furthermore, these substances also have a toxic effect in many cases. In general, the cancer risk depends on several factors such as genetic predisposition or environmental impact. Thus, there are no documented figures on the exact impact of hazardous substances. There is, however, proof that an increasing dose of these hazardous substances in welding fumes increases the risk of cancer. Scientists from the World Health Organization (WHO) have found an increased risk of lung cancer for welders.

For carcinogenic substances, no threshold value is known below which there is no longer any risk. Therefore, especially here, there is a need for minimization as per the Hazardous Substances Regulation. Examples for hazardous substances in welding fumes are:

  • Chrome (VI)-compounds: Irritation and chemical burns to the mucosa
  • Lead oxide: Nerve and kidney damage / Gastrointestinal disorders / Nausea
  • Nickel oxide: Carcinogen in the respiratory organs
  • Beryllium oxide: Metal fume fever / Chronic pneumonia
  • Cadmium oxide: Mucous membrane irritation / Hyperinflation
  • Cobalt oxide: Respiratory organ damage
  • Ozone: Mucous membrane irritation / Acute acute irritant gas poisoning / Delayed pulmonary edema
  • Formaldehyde: Severe mucosa irritation

Welding and Hexavalent Chromium in welding

Chromium (Cr) is a component in stainless steel, nonferrous alloys, chromate coatings and some welding consumables. During welding, Chromium is converted to its hexavalent state, Cr (VI). Cr (VI) fume is highly toxic and can damage the eyes, skin, nose, throat, and lungs and cause cancer.

  • OSHA regulates worker exposure to Cr (VI) under its Chromium (VI) standard, 29 CFR 1910.1026 and 1926.1126.
  • OSHA’s Permissible Exposure Limit (PEL) for Cr (VI) is 5 µg/ m3 as an 8-hour time-weighted average.

Reducing exposure to welding fume

  • Welders should understand the hazards of the materials they are working with. OSHA’s Hazard Communication standard requires employers to provide information and training for workers on hazardous materials in the workplace.
  • Welding surfaces should be cleaned of any coating that could potentially create toxic exposure, such as solvent residue and paint.
  • Workers should position themselves to avoid breathing welding fume and gases. For example, workers should stay upwind when welding in open or outdoor environments.
  • General ventilation, the natural or forced movement of fresh air, can reduce fume and gas levels in the work area. Welding outdoors or in open work spaces does not guarantee adequate ventilation. In work areas without ventilation and exhaust systems, welders should use natural drafts along with proper positioning to keep fume and gases away from themselves and other workers.
  • Local exhaust ventilation systems can be used to remove fume and gases from the welder’s breathing zone. Keep fume hoods, fume extractor guns and vacuum nozzles close to the plume source to remove the maximum amount of fume and gases. Portable or flexible exhaust systems can be positioned so that fume and gases are drawn away from the welder. Keep exhaust ports away from other workers.
  • Consider substituting a lower fume-generating or less toxic welding type or consumable.
  • Do not weld in confined spaces without ventilation. Refer to applicable OSHA regulations (see list below).

Respiratory protection may be required if work practices and ventilation do not reduce exposures to safe levels.

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