Introduction Copper and zinc containing welding fumes are suspected to induce inflammatory reactions, which, in humans, may result in metal fume fever. In a series of studies, early reactions of such welding fumes were investigated.

Methods Exposures were performed in the Aachen Workplace Simulation Lab. 15 healthy male subjects were exposed for 6 hours to average welding fume mass concentrations up to 2.5 mg m-3. Welding fumes resulted from Metal-Inert-Gas brazing of zinc coated steel using copper welding wire or resistance spot welding of zinc-coated steel. Inflammatory markers were measured in the blood or in nasal secretions prior to exposure, directly after or 24–29 hours after exposure.

Results The main results of these studies were:

• exposure to zinc and copper containing welding fumes lead to an asymptomatic inflammatory reaction as shown by an increase of blood C–reactive–Protein (CRP).

• Ultrafine resistance spot welding particles with similar composition and number concentration but lower mass concentration do not induce such reactions.

• Both, copper and zinc are individually able to induce such inflammation reactions. However, copper seems to have a higher potential for this induction.

• The inflammatory reaction is also reflected by an increase of Serum Amyloid A (SAA) and Interleukin 6 in the blood and by an increase of Interferon–λ and CRP in nasal secretions.

Discussion Since increases of CRP, SAA, and IL-6 indicate an increased risk for cardiovascular disease, exposure to zinc and copper containing welding fumes may have to be considered for the prevention of work related cardiovascular disease. Future studies should investigate, if the observed inflammatory reaction persists after repeated exposure