Silica exposure risk for rig workers during fracking

Sand

Sand transfer at a rig site for a fracking operation./NIOSH photo

OSHA issues hazard alert

High exposure to frack sand poses silicosis risk

Workers, industry must work together to ensure worker safety

Wyoming rig hands would do well to take notice of a national hazard alert warning that workers in hydraulic fracturing operations must be protected from silica exposure. Workers must use respirators and other safety equipment properly to maximize protection from the exposure. Federal regulators say industry likewise must do more to protect workers from the exposure. Exposure to silica can cause silicosis when small particles of silica sand become lodged in lung tissue and cause inflammation and scarring. The condition interferes with breathing because it reduces the ability of the lungs to absorb oxygen. Eric Esswein, a NIOSH scientist, studied the silica exposure risk of rig workers for months. He sampled air to measure dust levels and observed handling of sand used in hydraulic fracturing operations at a wide range of drilling sites. The hazard alerted noted that NIOSH worked with the oil and gas industry to sample air at 11 drilling sites in five states where fracking was taking place. The alert was issued June 21 by the federal Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health. The alert urged companies conducting hydraulic fracturing – commonly known as “fracking” – to take steps to protect workers from silica exposure. Industry and labor officials joined in the issuance of the alert. zThe oil and gas industry uses s combination of water and sand in hydraulic fracturing to drive sand crystals into rock formations to open passages for oil and gas to flow to a well bore for production. Esswein found sites where workers were were breathing air with more than 28 times the allowable exposure level to silica. Half-mask respirators protect workers from exposure levels only up to 10 times the allowable exposure, Esswein said during an April presentation at the University of Colorado medical campus in Denver. In comments on a NIOSH blog, Esswein wrote: “The magnitude of the exposures is particularly important; 36 of the 116 (31%) samples exceeded the NIOSH REL by a factor of 10 or more. The significance of these findings is that even if workers are properly using half-mask air-purifying respirators, they would not be sufficiently protected because half-mask air-purifying respirators have a maximum use concentration of 10 times the occupational health exposure limit.” Esswein also lists a number of ways to protect workers including:
  •  Use a less hazardous, non-silica material such as ceramic where feasible
  • Use local exhaust ventilation for capture and collection
  • Use passive enclosures at points of dust generation
  • Minimize the distances that sand must be moved
  • Replace belts with screw augers on sand movers
  • Use “amended water” – which contains chloride and magnesium – to reduce dust at the well site
  • Provide adequate training of workers about the hazards
  • Monitor workers to determine exposure
  • Use protective equipment until engineering controls are in place
Listen to a radio story by reporter Deborah Smith that includes ESPC and Petroleum Association of Wyoming comments on the OSHA-NIOSH hazard alert. It is available from the Public News Service. Elizabeth Grossman also addressed the alert in her blog “The Pump Handle”  on the National Geographic website.

Sand refill truck and dust release from “thief” hatches on the top of a sand mover./NIOSH photo

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