Background: Metal working fluids (MWF) constitute a significant respiratory hazard, although symptoms experienced by workers are often poorly investigated and attributed.
Aims: A single possible case of extrinsic allergic alveolitis (EAA) led to a formal workplace investigation. It was clear that other exposed workers were affected. The aim of this study was to accurately quantify the clinical, immunological and microbiological findings in MWF workers following presentation of a sentinel case.
Methods: Eleven of 21 individuals participated; eight were assessed by symptom questionnaire, spirometry and serology and three workers provided blood samples only. The microbes cultured from MWF and air samples were used to determine the presence of precipitating antibodies.
Results: Work-related respiratory symptoms were reported in six of eight individuals questioned, two of these complaining of 'flu-like' symptoms. Personal breathing zone measures identified 2.1 x 10(3) to 1.1 x 10(5) colony-forming units/m3 air (CFU/m3). Pseudomonas fluorescens was isolated from air samples. Despite visible 'fungal' contamination of MWF, airborne fungi were detectable in only one sample, at 486 CFU/m3 air. MWF cultured Eurotium sp., Fusarium sp. and Pseudomonas sp. Precipitating IgG antibodies to Pseudomonas sp. were identified in 4/11 and to an extract of the MWF in 3/11. IgG to Pseudomonas was elevated in the two individuals who had the strongest precipitating bands to Pseudomonas sp.
Conclusions: Workplaces with possible EAA must be investigated promptly, thus allowing clinical assessment to be contemporary to exposures and accurate microbiological profiling included to identify the likely cause.