Welding Fumes

Welding fumes are composed of metals and most fumes contain a small percentage of manganese. There is a concern by workers, employers, and health professionals about potential neurological effects associated with exposure to manganese in welding fumes. NIOSH has been conducting research and reviewing the published scientific literature to assess this problem.

Manganese is an essential nutrient. A healthy person with normal liver and kidney function can excrete excess dietary manganese. Inhaled manganese is of greater concern because it bypasses the body’s normal defense mechanisms. This can lead to manganese accumulation and adverse health effects including damage to the lungs, liver, kidney and central nervous system. Male workers exposed to manganese also have a higher risk of fertility problems. Prolonged exposure to high manganese concentrations (>1 mg/m³) in air may lead to a Parkinsonian syndrome known as “manganism.” Chronic exposure to the manganese-containing pesticide, maneb, is also reported to cause Parkinson-like symptoms. Parkinson-like symptoms may include tremors, slowness of movement, muscle rigidity, and poor balance.

What Are Welding Fumes?

Welding Fumes

Welding fumes are toxic metal fumes produced during welding operations. They usually have different compositions, depending on the metals that are used for welding, and for this reason they contain several contaminants.

Which fumes and gases are produced during welding?

Fumes

• Aluminum
• Beryllium
• Cadmium Oxides
• Chromium
• Copper
• Fluorides
• Iron Oxide
• Lead
• Manganese
• Molybdenum
• Nickel
• Vanadium
• Zinc Oxides

Gases

• Carbon Monoxide
• Hydrogen Fluoride
• Nitrogen Oxide
• Ozone

How can welding fumes and gases enter my body?

Welding fumes enter our body through the lungs, that is, we inhale them together with the air we breathe.

How can welding fumes affect your health?

Exposure to different types of welding fumes produce different health effects. If over the years you breathe in gases, fumes, and vapors in large quantities, your health will suffer.

• irritation of the eyes, nose, and chest
• coughing
• shortness of breath
• bronchitis
• fluid in the lungs (edema)
• Inflammation of the lungs (pneumonitis)
• Loss of appetite
• cramps
• nausea / vomiting

Some short-term health effects are:

• chronic lung problems (bronchitis, pneumonia, asthma, emphysema, silicosis, siderosis)
• lung cancer
• cancer of the larynx
• cancer of the urinary tract

Other health problems that may be related to welding fumes are:

• skin diseases
• hearing loss
• gastritis, ulcers of the stomach
• kidney damage
• heart disease

Effective control of gas shielded arc welding fume

HSE inspectors have noted that, although Local Exhaust Ventilation (LEV) was often available for controlling exposure to inert gas shielded welding fume, it frequently remained unused, due, partly to claims by welders that the LEV was responsible for removing shielding gas and thereby compromising the quality of the weld. However, there appeared to be few data to substantiate the welders’ claims. HSE commissioned this research project to establish whether efficient welding fume capture could be achieved using LEV whilst, at the same time, maintaining weld metal integrity. The objectives of this research project were to be met in three phases:

• Phase 1 was to provide the information necessary to develop an experimental plan.

• Phase 2 was to determine the maximum cross flow velocity of air that could be tolerated before the onset of weld metal porosity during gas shielded arc welding using parameters defined in Phase 1.

• Phase 3 was to measure capture efficiencies for a range of different LEV hoods positioned at various distances and orientations to the welding arc, whilst monitoring weld metal integrity. An on-gun extraction system was also evaluated. This report gives a brief summary of the work carried out in phase 1 and 2, and details the work carried out in phase 3

The report shows that when using standard welding parameters, satisfactory fume extraction is possible without compromising the weld integrity. The results are confirmed for a number of welding positions and with various extraction hoods in different positions. The results for the on-gun extraction equipment are evaluated against those observed for the stand-alone fume extraction equipment.

This report and the work it describes were funded by the Health and Safety Executive (HSE). The on-gun evaluation study was part funded by Nederman and Abicor-Binzel. Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

Tips for Welding, Cuttings and Brazing

* Safety and Health Fact Sheets: American Welding Society Fact Sheets covering aspects of safety and health applicable to welding and cutting. Includes subjects such as fumes and gases, radiation, noise and electrical hazards. Produced by the Labeling and Safe Practices Subcommittee of the AWS Safety and Health Committee.

* Electric Welding Safety: Workplace Safety and Health Division of the Manitoba Labour Department, Worksafe Bulletin Provides a short description of the hazards associated with electric arc welding and protective measures.

* Arc Welding Safety: University of Arizona College of Agriculture. The electric arc welder remains one of our most useful and timesaving pieces of shop equipment. Properly installed and used the arc welder is very safe, but if used improperly the operator can be exposed to a number of hazards, including toxic fumes, dusts, burns, fires, explosions, electric shock, radiation, noise, and heat stress.

* American Welding Society: The American Welding Society was founded in 1919 as a multifaceted, nonprofit organization with a goal to advance the science, technology and application of welding and related joining disciplines. Headquartered in Miami, Florida, AWS serves more than 48,500 members in the United States and around the world.

* NIOSH Strategic Research on Welding Identifies Data Needs: Some studies suggest that occupational exposures to welding fumes may pose the risk of serious respiratory, neurological, and reproductive effects. However, the available data generally are too limited to offer conclusive answers. Thus, scientists and policymakers face a need for more and better data.

* Welding Fumes Sampling: This summary prepared by MSHA provides guidance on hazards associated with welding and procedures for chemical sampling.

* Control Technology Assessment of Welding Operations A field study performed by identify, observe, and evaluate engineering control measures that may reduce the amount of fume a worker is exposed to during welding. Includes photos and figures of local exhaust systems.

Spot- Weldings

Spot welding is a type of resistance welding in which pieces of metals are pressed together and an electric current is passed through them. Spot welders are at risk of contact with some potentially hazardous agents but there are few studies about the respiratory effects of spot welding.

AIM: Our objective was to study lung function and respiratory symptoms among spot welders and office workers at an automobile assembly factory in Iran.

METHODS: This was a cross-sectional study of 137 male spot welders and 129 office workers. We used a questionnaire to record demographic data, smoking habits, work history and respiratory symptoms. Spirometry was performed to assess lung function status. Metal fume samples from the respiratory zone of spot welders were analysed.

The concentrations of metal fume were less than the American Conference of Industrial Hygienists (ACGIH) threshold limit values. There were significantly lower values for average forced expiratory volume in 1st second (FEV(1)), FEV(1)/forced vital capacity and 25-75% forced expiratory flow in spot welders compared to controls. There was also a significantly raised prevalence of respiratory symptoms (sputum and dyspnoea) in spot welding. Fifteen per cent of spot welders and 1% of controls had an obstructive pattern in spirometry.

CONCLUSION: Our survey suggests that spot welders are at risk of developing respiratory symptoms and decreasing pulmonary function values despite their exposure to components of welding fume being within ACGIH guidelines.