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Hazards From Exposure to Gases During Welding

Hazards From Exposure to Gases During Welding

Welding can generate gases that can be hazardous to your health.  Depending on the gas or gases generated and the concentration depends on the welding process you are using.  Whether the gases are used to provide a shield or as a consumable these different types of gases may be hazardous.  Many of these gases are well below the workplace exposure limits, but in some cases where the proper safety procedures have not been followed, they may exceed those limits.

When welding using the TIG, MIG/MAG processes the formation of a shielding gas is a natural and relevant result of these types of welding.  The main danger of welders working with this type of welding process is asphyxiation.  This may occur if the accumulation of these gases is greater than the amount of oxygen in the work area.  Without the proper ventilation and inspection of all connections and hoses being used the danger for asphyxiation is extremely high.

Carbon monoxide and carbon dioxide can be created when a flux welding process is being used.  Carbon monoxide is the more hazardous of the two gases; it can cause a reduction in oxygen, headaches, dizziness, nausea and weakness.  The production of carbon monoxide and carbon dioxide during regular types of flux welding is generally not a hazardous situation.  In some cases when high velocity oxy-fuel gas cutting is taking place, the potential for large quantities of carbon monoxide and carbon dioxide being created is much greater.  This process of welding involves large amounts of gas to be consumed in a short period of time; this may expose the welder to high levels of carbon monoxide which can cause health problems.

Nitrogen monoxide and nitrogen dioxide are typically generated by oxidation of nitrogen in the air and by heat caused from an arc or flame.  The acceptable limits of exposure limits to these gases are 1ppm per 8 hours is recommended for each gas.  Being overexposed to nitric acid can cause severe eye, skin and nose irritation.  Nitrogen dioxide is the more hazardous of the two gases, it is highly toxic.  The symptoms of overexposure to these gases is not immediately felt, it may take several hours for any of the symptoms to appear.  Sever overexposure to these two gases may result in the accumulation of water in the lungs which may restrict the supply of oxygen in the blood and in the most severe cases of overexposure death may occur.

The most common methods of welding typically produce small amount of nitrous gases so the risks of becoming overexposed are relatively small.  Exposure problems may occur when you are using a cutting method especially if the cutting is being done in a hand held manner.  This process places the worker closer to the gases.  The hotter the flame the higher the concentration of nitrous gas being produced is. 

Over exposure to ozone while welding typically occurs when there is a reaction between the UV light produced by the arc and oxygen in the air.  Ozone is only produced during arcing and disappears rather quickly after the arc is extinguished.  Therefore, ozone exposure is not one of the more dangerous gases to be exposed to while working.

While any over exposure to a gas while working is not preferable, it is important to take note of any recommendations pertaining to exposure limits before you begin work.  Insuring that you have proper ventilation equipment and have taken all necessary precautions is imperative to maintaining your safety and the safety of those around your work area.  If you feel that you may have been over exposed to any gases while working, it is imperative that you seek medical attention as soon as possible.

Ed C.


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