Toxic Substances Released During Welding Stainless Steel and Preventive Measures

A large number of toxic substances are released when welding stainless steel, posing a significant risk to the health of welders. 

Our article helps you understand these substances, how they enter the human body, the related hazards, and preventive measures. So that you can better ensure workplace safety and protect your health.

Is Welding Stainless Steel Toxic?

Yes, welding stainless steel can be toxic if proper safety precautions are not followed. When welding stainless steel, the heat can cause the release of harmful fumes. Inhalation of these fumes can lead to respiratory issues and long-term health risks, such as lung cancer.

What Toxic Substance Is Released When Welding Stainless Steel？

When welding stainless steel, the high temperatures cause the metal and any coatings to vaporize, releasing a mixture of metal fumes and gasses. These substances include hexavalent chromium, manganese, nickel, and a variety of other toxic gasses, each with unique properties and health implications.

Hexavalent Chromium in Stainless Steel

How Is It Produced?   

When chromium in stainless steel oxidizes at the very high temperatures at which it is welded, such as in high-temperature welding processes such as gas-shielded tungsten arc welding (GTAW), gas-shielded metal arc welding (GMAW), and shielded metal arc welding (SMAW), it converts the less hazardous Cr(Ⅲ) to the highly toxic Cr(Ⅵ).

How Does It Enter the Human Body?

Hexavalent chromium enters the body primarily through inhalation. These tiny hexavalent chromium particles travel deep into the lungs when breathed in and can damage the lungs. Hexavalent chromium can also enter the body through skin contact, especially in the case of injuries. Although less common, oral ingestion is also possible, such as touching your mouth with a hand contaminated with hexavalent chromium.

Welding Fumes Hazards

The health impacts of hexavalent chromium are severe and wide-ranging:

• Carcinogenicity: Cr(VI) is a known carcinogen, and long-term exposure can cause lung cancer.

• Respiratory Issues: Inhalation of Cr(Ⅵ) can cause a range of respiratory problems, including nasal and sinus cancers, asthma, chronic bronchitis, and respiratory tract irritation. Lung tissue can be permanently damaged, and lung function can be reduced by prolonged exposure.

• Dermal Effects: Skin contact with hexavalent chromium can cause severe dermatitis or chronic dermatitis requiring long-term treatment, skin ulcers, and allergic reactions.

• Systemic Toxicity: Cr(Ⅵ) can cause damage to various internal organs. It has been linked to kidney and liver damage, gastrointestinal distress, and immune system dysfunction.

• Ocular Damage: Direct eye contact with Cr(Ⅵ) compounds can lead to severe eye irritation, damage to the cornea, and even permanent vision loss.

Preventive Measures

• Ventilation: Install a local exhaust ventilation (LEV) system to remove fumes at the source before they spread into the work environment. General ventilation should also be improved to dilute airborne contaminants.

• Personal Protective Equipment (PPE): Welders should wear appropriate respiratory protection equipment, such as N95 or P100 masks, to filter Cr(VI) particles; they should also wear protective clothing, gloves, and goggles to prevent Cr(VI) from contacting the skin and eyes.

• Process Modification: Opt for welding techniques that produce fewer fumes, such as using low-chromium or chromium-free materials. Techniques like laser welding or electron beam welding can also reduce fume production.

• Work norms: Develop good hygiene habits and clean the work surface regularly to remove any deposited hexavalent chromium particles. Hands and face should be washed thoroughly before eating or drinking, and do not smoke in the work area.

• Monitoring: Conduct air quality monitoring to ensure that the levels of hexavalent chromium remain within safe limits. This involves using personal air sampling devices and fixed-point air monitors to continuously assess airborne Cr(Ⅵ) concentrations.

• Medical Surveillance: Regular health check-ups for welders to monitor for early signs of Cr(Ⅵ) exposure-related health issues. This includes respiratory function tests, skin examinations, and cancer screenings.

Manganese

How Is It Produced?

Manganese fumes are generated when welding stainless steel containing manganese, which is often added to improve the material’s strength and durability. The intense heat of the welding process vaporizes the manganese, releasing it into the air as fine particulate matter.

How Does It Enter the Human Body and Welding Fumes Hazards

These tiny manganese particles enter the body primarily through inhalation and travel deep into the respiratory system, reaching the alveoli in the lungs.

Exposure to manganese can cause bronchitis and decreased lung function. Long-term exposure to manganese fumes can lead to a neurological disorder called manganese poisoning. Symptoms of manganese poisoning include tremors, difficulty walking, facial muscle spasms, and other Parkinson’s-like symptoms.

Preventive Measures

• Ventilation and Filtration: Use high-efficiency particulate air (HEPA) filters and local exhaust ventilation to remove manganese particles from the air.

• Respiratory Protection: Provide welders with respirators that are specifically made to filter out fine particulate matter.

• Work Practices: Implement work practices that minimize the generation of manganese fumes, such as reducing welding current and using welding processes that produce fewer fumes.

• Medical Surveillance: Regular health check-ups for welders to monitor for early signs of manganism.

Nickel

How Is It Produced?

Nickel fumes are released during the welding of stainless steel and nickel alloys. The high temperatures required for welding cause the nickel to vaporize, forming nickel oxide fumes.

How Does It Enter the Human Body and Welding Fumes Hazards

Inhalation is the primary route through which nickel fumes enter the body. 

Nickel exposure can cause immediate respiratory irritation, coughing, and shortness of breath. Long-term exposure increases the risk of developing lung and nasal cancers. In addition, nickel can cause allergic reactions such as contact dermatitis.

Preventive Measures

• Ventilation Systems: Utilize both local and general ventilation to reduce airborne nickel concentrations.

• Protective Equipment: Ensure welders use appropriate respiratory protection and protective clothing.

• Workplace Hygiene: Maintain good hygiene habits, wash your hands and face before eating or drinking, and clean the work area in time.

• Alternative Materials: When possible, use alternative materials that do not contain nickel or have lower nickel content.

Zinc Oxide

How Is It Produced?

Zinc oxide fumes are produced when welding galvanized steel or zinc-coated metals. The intense heat of welding vaporizes the zinc coating, releasing zinc oxide fumes.

How Does It Enter the Human Body and Welding Fumes Hazards

Zinc oxide enters the body through inhalation and causes metal fume fever, a disease with symptoms similar to the flu, such as fever, chills, nausea, and muscle aches.

Prolonged exposure to zinc oxide may cause respiratory problems and lead to impaired lung function. Also, high concentrations of zinc oxide may cause gastrointestinal distress and anemia symptoms.

Preventive Measures

• Removal of Coatings: Remove zinc coatings from metals before welding to minimize fume generation.

• Ventilation and Extraction: Use local exhaust ventilation to capture zinc oxide fumes at the source.

• Personal Protective Equipment: Provide welders with appropriate respirators and protective clothing.

• Work Practices: Implement work practices that reduce exposure, such as welding in well-ventilated areas and taking regular breaks.

Carbon Monoxide (CO)

How Is It Produced?

Carbon monoxide is produced by incomplete combustion of carbon-containing materials during welding, for example, when using carbon dioxide as a shielding gas.

How Does It Enter the Human Body and Welding Fumes Hazards

After carbon monoxide enters the human body through inhalation, it binds to hemoglobin in the blood, reducing the blood’s ability to deliver oxygen to tissues and organs.

Excessive inhalation of carbon monoxide (CO) can cause carbon monoxide poisoning. Its symptoms include headache, dizziness, vomiting, chest pain, etc. Inhalation of large amounts can cause loss of consciousness and even death. Long-term complications include fatigue, memory loss, and movement problems.

Preventive Measures

• Preventive measures for carbon monoxide exposure include:

• Ventilation: Ensure proper ventilation in the welding area to disperse carbon monoxide.

• Monitoring: Use carbon monoxide detectors to monitor levels in the workplace.

• Protective Equipment: Provide welders with respirators that filter out carbon monoxide.

• Training: Educate workers on the risks of carbon monoxide and safe work practices to minimize exposure.

Ozone (O3)

How Is It Produced?

Ozone is produced during welding processes that generate UV light, such as gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW), where the UV light interacts with oxygen to form ozone.

How Does It Enter the Human Body and Welding Fumes Hazards

Ozone enters the body through inhalation. It is a powerful respiratory irritant that can cause symptoms such as coughing, throat irritation, chest pain, and shortness of breath.

Ozone can aggravate existing lung diseases. Long-term exposure to ozone can cause asthma and chronic respiratory diseases.

Preventive Measures

• Ventilation Systems: Use adequate ventilation to disperse ozone away from the welding area.

• Protective Equipment: Equip welders with respirators that filter out ozone.

• Work Practices: Implement work practices that minimize the production of ozone, such as reducing welding current and using alternative welding processes.

Is Welding Stainless Steel Dangerous?

Yes, welding stainless steel releases toxic fumes, particularly hexavalent chromium and nickel compounds, which can cause harm when breathed in. Without proper ventilation and protective equipment, exposure to these fumes can cause serious health problems, including breathing problems, lung damage, and an increased risk of cancer.

Side Effects of Welding Stainless Steel

Welding stainless steel can lead to various side effects if safety precautions are not followed, including:

• Respiratory issues such as asthma, bronchitis, or lung irritation from inhaling toxic fumes.
• Metal fume fever, a flu-like illness caused by inhaling metal oxides.
• Long-term risks, including an increased likelihood of developing lung cancer or kidney damage due to prolonged exposure to hexavalent chromium.
• Skin and eye irritation from ultraviolet (UV) light and heat produced during the welding process.

Stainless Steel Poisoning Symptoms

Stainless steel poisoning, mainly from exposure to hexavalent chromium and nickel, can cause symptoms like:

• Breathing difficulties or wheezing
• Irritation of the nose, throat, and lungs
• Coughing or sore throat
• Metallic taste in the mouth
• Nausea, fever, or flu-like symptoms (metal fume fever)
• In severe cases, kidney or liver damage may occur due to long-term exposure to hazardous fumes.

How to Prevent Inhaling Stainless Steel Welding Fumes?

Managing the hazards arising from the inhalation of welding fumes requires a multi-faceted approach, including improvement of the working environment, enhancement of personal protection, promotion of occupational health awareness, and regular health surveillance. The following are some specific management measures.

Improving the Working Environment

Ventilation protection

• Where conditions permit, try to maintain natural ventilation in the workplace to reduce the concentration of welding fumes.
• In the closed or semi-closed working environment, mechanical ventilation equipment should be installed, such as exhaust fans, smoke exhaust systems, etc., to ensure air circulation and timely discharge of welding fumes outside.

Process Improvement

• Promote the use of low-smoke, low-toxicity welding materials and processes to reduce the generation of welding fumes.
• Adopt advanced welding technology, such as laser welding, friction stir welding, etc., which produce relatively less smoke.

Strengthen Personal Protection

Respiratory protection

• Equip welding operators with standardized filtering respirators or gas masks to ensure that they can effectively filter harmful substances in welding fumes.
• Regularly check the completeness and filtering effect of respiratory protection equipment, and timely replacement of damaged or expired parts.

Eye and skin protection

• Wear protective eyewear or face shields to prevent eye irritation and damage caused by welding fumes.
• Wear special work clothes and gloves to reduce the chance of direct contact between skin and welding fumes.

Raising Awareness of Occupational Health

Occupational health education

• Educate welding operators on occupational health knowledge so that they understand the hazards of welding fumes and the importance of protective measures.
• Regularly organize emergency drills to improve the emergency response capabilities of welding operators in unexpected situations.

Self-management

• Welding operators should consciously abide by the occupational health management system and use personal protective equipment correctly.
• Pay attention to personal hygiene habits, such as washing hands and changing clothes, etc., to reduce the chance of harmful substances entering the body through the skin or mouth.

Regular Health Monitoring

Occupational health check

• Employers should regularly organize welding operations personnel for occupational health checks, including lung function tests, eye examinations, etc., in order to early detection of potential health problems.
• For welding operators found to be suffering from occupational diseases, treatment and rehabilitation should be carried out in a timely manner.

Environmental monitoring

• Regularly monitor the air quality of the welding workplace to assess the concentration of welding fumes and the types and levels of hazardous substances.
• Ventilation protection and personal protection measures are adjusted according to the monitoring results to ensure the safety of the working environment.

OSHA Standard 

The standards set by the Occupational Safety and Health Administration (OSHA) to protect workers from the hazards associated with welding fumes mainly cover several aspects to ensure workplace safety and worker health. Key regulations include:

Permissible Exposure Limits (PELs): OSHA sets PELs for various hazardous substances, including hexavalent chromium (5 µg/m3), manganese (5 mg/m3 ceiling), and nickel (1 mg/m3).

Exposure Monitoring: Employers must conduct regular air monitoring to measure workers’ exposure levels and ensure they are within the PELs.

Ventilation requirements: The standard requires employers to take necessary ventilation measures, such as installing local exhaust systems and maintaining natural ventilation, to reduce the concentration of harmful substances in the workplace. For workers who may be exposed to harmful substances such as welding fumes, employers must provide appropriate respiratory protective equipment.

Training and Education: OSHA requires employers to provide workers with occupational safety and health training, especially training on the hazards and protective measures of hazardous substances such as welding fumes.

Medical Surveillance: For workers exposed to certain hazardous substances, OSHA mandates medical surveillance to monitor their health and detect early signs of adverse effects.

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