Occupational exposure to airborne contaminants during offshore oil drilling

Abstract

The aim was to study exposure to airborne contaminants in oil drillers during ordinary work. Personal samples were collected among 65 drill floor workers on four stationary and six moveable rigs in the Norwegian offshore sector. Air concentrations of drilling mud were determined based on measurements of the non-volatile mud components Ca and Fe. The median air concentration of mud was 140 μg m(-3). Median air concentrations of oil mist (180 μg m(-3)), oil vapour (14 mg m(-3)) and organic carbon (46 μg m(-3)) were also measured. All contaminants were detected in all work areas (drill floor, shaker area, mud pits, pump room, other areas). The highest air concentrations were measured in the shaker area, but the differences in air concentrations between working areas were moderate. Oil mist and oil vapour concentrations were statistically higher on moveable rigs than on stationary rigs, but after adjusting for differences in mud temperature the differences between rig types were no longer of statistical significance. Statistically significant positive associations were found between mud temperature and the concentrations of oil mist (Spearman's R = 0.46) and oil vapour (0.39), and between viscosity of base oil and oil mist concentrations. Use of pressure washers was associated with higher air concentrations of mud. A series of 18 parallel stationary samples showed a high and statistically significant association between concentrations of organic carbon and oil mist (r = 0.98). This study shows that workers are exposed to airborne non-volatilized mud components. Air concentrations of volatile mud components like oil mist and oil vapour were low, but were present in all the studied working areas.

Pulmonary function and high-resolution computed tomography examinations among offshore drill floor workers

“…Mud circulates between the drill hole and drilling rig. During drilling, the returning mud is separated from the cuttings in the mud handling area of the rig with the use of shale shakers (Kirkhus et al 2015 ).…”

“…Exposure to oil mist in the Norwegian offshore sector has decreased since the 1980s, from around 4.3 mg/m 3 (arithmetic mean) in the time period from 1989 to 1997 to 0.54 mg/m 3 during 1998–2004 (Steinsvåg et al 2006 ). A recent study showed median oil mist concentrations of 0.18 mg/m 3 during 2010 and 2011 (Kirkhus et al 2015 ). Also, non-volatile mud components (NVM) are present in the working atmosphere of the drill floor workers (Hansen et al 1991 ; Kirkhus et al 2015 ).…”

“…A recent study showed median oil mist concentrations of 0.18 mg/m 3 during 2010 and 2011 (Kirkhus et al 2015 ). Also, non-volatile mud components (NVM) are present in the working atmosphere of the drill floor workers (Hansen et al 1991 ; Kirkhus et al 2015 ). This exposure has not been regularly assessed, although oil-based and water-based drilling fluids are alkaline solutions, and mud aerosols may have alkaline properties (Hansen et al 1991 ; OGP/IPIECA, Drilling Fluid Task Force 2009 ).…”

“…The formation of oil particles during oil drilling is a combination of mechanical and thermal generation (Kirkhus et al 2015 ). Mechanically generated aerosols contain all the chemical components present in the drilling mud.…”

“…This study is part of a larger investigation of drill floor workers’ exposure and pulmonary health (Kirkhus et al 2015 ). The aim of this study was to assess whether current exposure to airborne contaminants during oil drilling with oil-based mud is associated with short-term changes in pulmonary function in drill floor workers (Part 1).…”