Hazardous substances during welding work

Welding, thermal cutting and spraying as well as soldering generates welding fumes that are hazardous to health. The welding fume particles contained therein are dangerous to humans. These can belong to dust fraction A. In this case, the welding smoke particles are alveolar. Class E welding fume particles are inhalable. 95 % of the particulate hazardous substances are generated during welding work from filler materials. These are usually metal oxides during welding work.

In addition to particles, welding fumes can contain gaseous hazardous substances. These are produced during machining processes such as gas welding and flame blasting.

• Ozone: This hazardous substance is mainly produced when radiation-reflecting materials are welded. These include aluminium sheets and chrome-nickel steels (MIG). Ozone exposure is particularly severe in low-smoke welding (TIG). The hazardous substance is one of the carcinogenic substances mentioned in the list of hazardous substances.
• Phosgene: The hazardous substance is produced during welding work at temperatures above 300 °C. The toxic gases released during this process cause a caustic reaction on the mucous membranes and skin.

Hazardous substances in metalwork machining

The risk in metal machining with cooling lubricants is a major factor. The main component of cooling lubricants are oils and those are supplemented by additives. The water-mixed cooling lubricants supplied by the manufacturer consist of 90 % water. The use of cooling lubricants become dangerous when foreign substances mix with the cooling lubricants during the metalworking process. Foreign substances include metal abrasions or hardening salts. Colonisation of the cooling lubricants with moulds or bacteria is also possible. Unprotected handling of cooling lubricants often leads to skin diseases such as contact dermatitis. Cooling lubricant vapours bear the risk of respiratory diseases. N-nitrosamines are particularly dangerous. Those must not be contained in the cooling lubricants of the suppliers. Nevertheless, there is a risk that nitrite can get into the cooling lubricant emulsions via, for example, nitrogen oxides from the air.

Hazardous substances for surface treatment

Paints, varnishes, adhesives and/or thinners are used in the treatment of surfaces. The solvents contained in them pose health risks to humans. Paints and varnishes partly contain organic binders, solvents and pigments as well as fillers and paint additives. Dispersion paints contain additives, which affect the skin on direct contact. The higher the volatility of the solvents in the paints or varnishes is, the stronger the solvent vapours are. There is risk of explosion when solvents evaporate. Inhalation of the solvents cause damages to the lungs, liver, kidneys and bone marrow to name a few. The occurrence of fatigue as well as irritated eyes or headaches are first signs of a narcotic effect. During processes such as the sanding of painted objects, the coating is damaged and harmful dust is generated. Those contain hazardous substances cadmium oxides or lead oxides among other things. Thinners and adhesives are also hazardous as they contain solvents just like paints and varnishes.

Hazardous substances in plastics processing

Plastic is a popular material used by many companies. In its cured state, plastic is not a hazardous material, on the other hand mechanical processing of plastic generates dust, among other things. However, those plastic dusts along with dangerous gases or vapours, which are to be expected when processing plastic that requires high temperatures, pose a major health risk. Risks are associated with the use of polyurethane plastics for adhesives or foams, polyester resins for adhesives and the use of epoxy resins. The latter are used for glass fibre reinforced plastics, among other things. Irritation of the respiratory tract, which can lead to asthma, and skin irritation are health risks posed by the plastics.