title: Oil mist and vapour concentrations from drilling fluids: inter- and intra-laboratory comparison of chemical analyses.
abstract: OBJECTIVE
  There are no recognized analytical methods for measuring oil mist and vapours arising from drilling fluids used in offshore petroleum drilling industry. To inform the future development of improved methods of analysis for oil mist and vapours this study assessed the inter- and intra-laboratory variability in oil mist and vapour analysis. In addition, sample losses during transportation and storage were assessed.
  
  
  METHODS
  Replicate samples for oil mist and vapour were collected using the 37-mm Millipore closed cassette and charcoal tube assembly. Sampling was conducted in a simulated shale shaker room, similar to that found offshore for processing drilling fluids. Samples were analysed at two different laboratories, one in Norway and one in the UK. Oil mist samples were analysed using Fourier transform infrared spectroscopy (FTIR), while oil vapour samples were analysed by gas chromatography (GC).
  
  
  RESULTS
  The comparison of replicate samples showed substantial within- and between-laboratory variability in reported oil mist concentrations. The variability in oil vapour results was considerably reduced compared to oil mist, provided that a common method of calibration and quantification was adopted. The study also showed that losses can occur during transportation and storage of samples.
  
  
  CONCLUSIONS
  There is a need to develop a harmonized method for the quantification of oil mist on filter and oil vapour on charcoal supported by a suitable proficiency testing scheme for laboratories involved in the analysis of occupational hygiene samples for the petroleum industry. The uncertainties in oil mist and vapour measurement have substantial implications in relation to compliance with occupational exposure limits and also in the reliability of any exposure-response information reported in epidemiological studies.
authors.affiliation: Institute of Occupational Medicine (IOM), Research Avenue North, Riccarton, Edinburgh, UK. karen.galea@iom-world.org
authors.forename: Karen S
authors.initials: KS
authors.lastname: Galea
authors.forename: Alison
authors.initials: A
authors.lastname: Searl
authors.forename: Araceli
authors.initials: A
authors.lastname: Sánchez-Jiménez
authors.forename: Torill
authors.initials: T
authors.lastname: Woldbæk
authors.forename: Kristin
authors.initials: K
authors.lastname: Halgard
authors.forename: Syvert
authors.initials: S
authors.lastname: Thorud
authors.forename: Kjersti
authors.initials: K
authors.lastname: Steinsvåg
authors.forename: Kirsti
authors.initials: K
authors.lastname: Krüger
authors.forename: Laura
authors.initials: L
authors.lastname: Maccalman
authors.forename: John W
authors.initials: JW
authors.lastname: Cherrie
authors.forename: Martie
authors.initials: M
authors.lastname: van Tongeren
mesh_terms: D000336:Aerosols; D000395:Air Pollutants, Occupational / Q000032:analysis* / Q000737:chemistry; D002849:Chromatography, Gas; D004784:Environmental Monitoring / Q000379:methods; D019652:Extraction and Processing Industry; D005583:Fourier Analysis; D006801:Humans; D007219:Industrial Oils / Q000032:analysis*; D013055:Spectrophotometry, Infrared
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational