Super Categories

Subcategories

Known Synonyms

Welding of stainless steel is a well recognised cause of occupational asthma, the chrome in the fume has been shown to be the cause in some challenge tests. Non-stainless steel welding is more problematic as specific causative agents have not been demonstrated, but nevertheless occupational asthma occurs. Probably the best evidence comes from longitudinal studies of apprentice welders.   

El-Zein, M, European Respiratory Journal 2003; 22: 513 is a study in Canada of 286 students entering welding profession apprenticeship with assessments before exposure and on average 15 months later. About 3% (6 of 194) developed occupational asthma and 11.9% new bronchial reactivity, often a precursor of asthma. There have also been studies of populations, looking at the excess of amount of asthma seen in welders as opposed to the general population.  One in Sweden – Toren K, Scandinavian Journal of Work Environmental Health 1999; 25:430.  Welding fume exposure was amongst those with increased odds ratio for developing physician diagnosed asthma.

There is one report of non chrome, non cobalt welding causing occupational asthma and confirmed by Specific bronchial provocation testing (Vandenplas O, Thorax 1995; 50:587).

There are several studies of workplaces looking at welders v others, finding more respiratory disease in welders.  One more recent study is by Loukzadeh Z, Occupational Medicine 2009; 59:267 showing that spot welding fumes at levels less than the exposure limits associated with significantly lower FEV1 values and increased respiratory symptoms.

Finally, there is evidence from the reporting schemes for occupational asthma in the UK from chest physicians (SWORD) and from occupational physician (OPRA).   The evidence required for reporting is more likely than not (i.e., in the balance of probabilities) to be due to the agent specified.  A core group report all cases whereas most report one month out of every twelve (the values are therefore multiplied by 12 for those reporting one month in twelve).  Welding fume is one of the more commonly recognised causes of occupational asthma.  There have been 121 actual cases of occupational asthma from non stainless steel welding reported 1989-2007 with 268 estimated.