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Published: December, 2008; Vol 5, Num 7

 

Torch Toxic Hazards

Laborers often work closely with welders. Sometimes, they are bystanders in environments where welding is taking place, and they frequently perform demolition tasks, such as torch-cutting, that expose them to the same toxins. It is imperative that all workers understand the damaging effects of welding fumes and other chemicals released in torch operations. Caution must be exercised when working around these hazards.

Recommendations from CPWR:
The Center for Construction Research and Training

  • Remove all paint and solvents before welding or torch-cutting. Make sure all residues are removed.
  • Use the safest welding method for the job. Stick welding makes much less fume than flux core welding.
  • Use welding rods that produce a low fume. Up to 90 percent of the fume can come from the rod. Welding guns that extract fumes can capture 95 percent of the fume.
  • In a confined space, follow all the OSHA confined-space rules — like air monitoring, not storing torches in the space and ventilation.
  • Ensure good ventilation.
  • Use local-exhaust ventilation to remove fumes and gases at their source in still air. Keep the exhaust hood opening four to six inches from the fume source.
  • Use air blowers to blow fumes away from you.
  • Keep your face far from the welding plume.
  • If the ventilation is not good, use a respirator. If respirators are used, OSHA requires employers to have a full respiratory protection program. This means proper selection and fitting of respirators, medical screening to be sure a worker can wear a respirator and worker training. Correct respirator storage and cleaning and an evaluation of the program are also necessary.
  • If you smoke, quit.

Welding is the joining of materials such as metals and thermoplastics by liquefying their parts and bonding them together. Fumes and respirable particles in the welding environment contain chemicals that can cause adverse side effects after inhalation. In a confined space, the gases can overpower oxygen in the air, making it difficult to breathe and sometimes causing asphyxiation. Torch-cutting involves heating metal so that it can be separated into two or more segments. In the process, fumes from the metal as well as any coatings on it are released into the air.

One of the most neurologically damaging chemicals is manganese (Mn). Exposure is prevalent in many welding operations. According to the American Conference of Governmental Industrial Hygienists (ACGIH), the threshold limit value for manganese is 0.2 mg/m3 time-weighted-average, yetOSHA’s permissible exposure limit is 25 times higher at 5.0 mg/m3. However, according to the National Institute for Occupational Safety and Health (NIOSH), levels of manganese less than 0.2 mg/m3 have been known to cause a decrease in brain function and motor skills.

The symptoms (e.g., tremors, shakes, loss of balance, slower response speed, trouble walking, impotency, slurred speech, extreme drowsiness or nighttime leg cramps) are collectively called “manganism” and can be very similar to those of Parkinson’s disease. However, medical evidence linking manganese exposure to Parkinson’s Disease is inconclusive, and it has stirred a controversy in the occupational safety and health community (read “Toxic Smoke and Mirrors”). For further information, read Safety and Health Topic: Welding and Manganese: Potential Neurologic Effects (NIOSH) online.

Manganese is not the only hazard of welding and torch-cutting. The following are some of the toxins listed by OSHA that are released during these operations:

  • Zinc is necessary for protecting metals from erosion as well as the manufacture of brass. When welding with zinc-coated materials, the process gives off a fume called zinc oxide. Inhaling this fume can cause flu-like symptoms known as “metal fume fever.” The exposed worker may experience a high temperature, cough, sweating, chills, nausea, dry throat and fatigue.
  • Cadmium can be found in zinc and is often used to protect steel from rusting. While it shares many similarities with zinc, this substance is far more toxic. OSHA, NIOSH and the Environmental Protection Agency (EPA) find cadmium to be a cancer-causing agent. Inhalation can cause metal fume fever, severe lung irritation and pulmonary edema. If exposed to cadmium over a long period of time, a worker can also suffer from emphysema and kidney damage. Mercury also protects metals from rusting. The government listed mercury as a toxic pollutant in the 1990 Clean Air Act. By federal law, the use of mercury must be controlled to the greatest extent possible via engineering and administrative controls and personal protective equipment (PPE). Its vapor can be released into the air during welding, and when inhaled, it can cause stomach pain, diarrhea, kidney damage or respiratory failure. Long-term exposure may produce tremors, emotional instability and hearing damage.
  • Lead has long been known to be a toxic substance. Welding and cutting metals that contain lead or are coated with lead paint expose workers to dangerous toxins that enter the lungs and blood stream. Elevated levels of lead are commonly called lead poisoning. In the most severe cases, it can cause neurological disorders. Symptoms include a metallic taste in the mouth, loss of appetite, nausea, abdominal cramps and insomnia.

The release of carbon monoxide is also associated with welding and cutting. It is especially dangerous in confined spaces or areas with poor ventilation. Carbon monoxide is odorless and colorless, yet inhalation can be fatal. Mild exposure to this gas can cause headaches, dizziness, ringing in the ears and nausea. High levels of carbon monoxide inhalation can rob a worker’s body of oxygen. For a complete list of welding toxins, including physical and chemical agents, visit the Welding Health Hazards section in OSHA’s online Construction Safety and Health Outreach Program.

You can protect yourself from torch toxic hazards on the job. See the recommended precautions in the sidebar. Also, the LHSFNA publishes a health alert on welding fumes and gases. To order, go online to the LHSFNA web site. Also, read Welding Fume Dangers Get Fresh Scrutiny in LIFELINES ONLINE for more information.

[Jennifer E. Jones]