Thermal metal spray poses significant health hazard (February 01, 2006)

Metal-based coatings are useful for building up worn parts, applying a corrosion-resistant layer or soldering or brazing filler metals. The process of applying them, however, generates toxic dusts, gases, fumes and radiation that can pose a lethal hazard to workers.

The Washington State Department of Labour and Industries reports that a man in Washington State in the U.S. died in 2003 as a result of spending two days applying chromium- and nickel-based thermal sprays at a worksite using portable equipment. The temporary worksite had inadequate ventilation. The worker did not have an appropriate respirator, nor was he wearing any other personal protective equipment as he worked.

Thermal metal spraying, also known as flame spraying, metal spraying, plasma spraying, electric arc spraying, metallizing, and hardfacing, is the process in which metals are melted and sprayed on a surface to form a coating.

The metals may be melted using a variety of heating processes, and sprayed metals can be pure metals or alloys in the form of powders, wires, or rods.

Aerospace, agriculture, automotive, electronic, machine shops, marine, pulp and paper, and transportation are just some of the industries that use thermal metal spray.

The operator and anyone else in the vicinity of the work are at risk of several types of hazardous exposure. Besides posing a respiratory hazard, thermal metal spraying is also a noisy process that can damage the worker’s hearing.

It poses other hazards as well, including those associated with electrical and mechanical processes, fire and explosion, heat or high temperatures, compressed gases, and infrasound (sub-audible sound).

To protect workers from the hazards of thermal metal spraying, consult your equipment manufacturer and spray-material suppliers about how to ensure that the equipment is being used according to recommended operating guidelines. Find out how to assess the hazards before the job takes place, and how to take appropriate precautions.

Workplaces that use thermal metal spraying should provide appropriate safety training for workers, adequate ventilation, programs for respiratory protection and hearing conservation, as well as additional personal protective equipment.