Machine Operator's Lung. A Hypersensitivity Pneumonitis Disorder Associated With Exposure to Metalworking Fluid Aerosols

Chest. 1995 Sep;108(3):636-41. doi: 10.1378/chest.108.3.636.


Six auto parts manufacturing workers were referred for evaluation of a 6-week history of work-related dyspnea, cough, and fatigue. Two workers also reported fever and weight loss. All six worked in a machining area where a waterbased metalworking fluid was used and recirculated under high pressure, thereby creating an aerosol. Chest radiographs revealed pulmonary interstitial infiltrates in four workers. Lung function tests showed that four workers had decreased diffusing capacity. After removal from the work area, all workers recovered. The metalworking fluid was cultured for bacteria and fungi. Isolates from broth cultures were sonicated to obtain antigen extracts. Serum precipitins to one or more of the microbial isolates were identified in all six workers but not in eight of nine nonexposed control subjects. The most frequent precipitin response (six of six workers) was against antigens of Pseudomonas fluorescens, which was cultured from the metalworking fluid. In all workers, precipitins to at least one other cultured organism were detected; these included Aspergillus niger, Staphylococcus capitas, an acid-fast Rhodococcus sp, and Bacillus pumilus. This represents the first report of hypersensitivity pneumonitis associated with industrial exposure to aerosolized metalworking fluid. Observed precipitin responses to a variety of microbial contaminants in metalworking fluid strongly suggest a causative role for microbial antigens in the induction and elicitation of this manifestation of hypersensitivity pneumonitis.

MeSH terms

  • Adult
  • Aerosols
  • Alveolitis, Extrinsic Allergic / chemically induced*
  • Alveolitis, Extrinsic Allergic / epidemiology
  • Alveolitis, Extrinsic Allergic / microbiology
  • Equipment Contamination
  • Humans
  • Male
  • Metallurgy*
  • Occupational Diseases / chemically induced*
  • Occupational Diseases / epidemiology
  • Occupational Diseases / microbiology
  • Occupational Exposure / adverse effects*
  • Precipitins / analysis
  • Pseudomonas Infections / diagnosis
  • Pseudomonas Infections / etiology
  • Pseudomonas fluorescens / isolation & purification
  • Respiratory Function Tests


  • Aerosols
  • Precipitins