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Silica. It’s Not Just Dust Rick Gleason, CIH, CSP October 8, 2009

Silica. It’s Not Just Dust Rick Gleason, CIH, CSP October 8, 2009. Rick Gleason, CIH, CSP rgleason@u.washington.edu (206) 856-6660. 1. History of Silica 2. L & I Regulations 3. UW Airborne Silica Sampling 4. Questions. Hawk’s Nest Tunnel West Virginia, 1932. In Nature Beach sand

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Silica. It’s Not Just Dust Rick Gleason, CIH, CSP October 8, 2009

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  1. Silica. It’s Not Just Dust Rick Gleason, CIH, CSP October 8, 2009

  2. Rick Gleason, CIH, CSPrgleason@u.washington.edu(206) 856-6660

  3. 1. History of Silica2. L & I Regulations3. UW Airborne Silica Sampling4. Questions

  4. Hawk’s Nest Tunnel West Virginia, 1932

  5. In Nature Beach sand Granite Sandstone Clays Diatomaceous earth In Industry Mining Quarrying Stone cutting Sand blasting Concrete & mortar work Cutting, grinding, drilling, sanding Where is it found?

  6. Silica Exposure • Size of particles - can it be inhaled deep into the lung? • % silica in the dust • Concentration • How much time exposed each day? • How often exposed?

  7. What is Sililcosis • A Fibrotic disease of the lungs – it scars the lung tissue • Lung is less flexible and has less area for the exchange of oxygen • Makes it difficult to do hard work and breath • May be from short-term high exposure (acute) or long-term lower exposure (chronic)

  8. Silicosis • Incurable and irreversible • May progress even after exposure has stopped • This is completely preventable!

  9. Risk of Developing Silicosis* * Flinn et al, 1939

  10. Other Health Problems Related to Silica Exposure • Lung Cancer • More susceptible to tuberculosis • Maybe immune system disease • Kidney disease

  11. Silica Exposures Labor and Industries Rules

  12. Standard 10 (d) Sanitation and Cleanliness

  13. Labor and Industries Industrial Hygiene CodesWhat year???

  14. October 1, 1938

  15. Video: Stop Silicosis1938Available from the L & I DOSH Video Lending Library

  16. UW Research –ExposureWhat did we find? • 1,375 personal quartz samples • Geometric mean quartz concentration: • 0.13 mg/m3 • compare to Washington PEL of 0.1 mg/m3

  17. 9% 36% 55%

  18. Exposure by Tool Used

  19. Tool: abrasive blaster No.= 57 0.28 mg/m3 Range 0.01 – 832.71 mg/m3

  20. Tool: hand-held saw No.= 65 0.13 mg/m3 Range <0.01 – 14.15 mg/m3

  21. Tool: table saw No.= 51 0.07 mg/m3 Range 0.01 – 2.75 mg/m3

  22. Tool: walk-behind saw No.= 33 0.09 mg/m3 Range 0.02 – 1.64 mg/m3

  23. Tool: rock drill No.= 93 0.21 mg/m3 Range <0.01 – 16.00 mg/m3

  24. Tool: jackhammer/chipping gun No.= 178 0.15 mg/m3 Range <0.01 – 3.86 mg/m3

  25. Tool: broom/shovel No.= 49 0.03 mg/m3 Range <0.01 – 1.19 mg/m3

  26. Tool: surface grinder No.= 123 0.28 mg/m3 Range 0.01 – 18.20 mg/m3

  27. Tool: tuckpoint grinder No.= 102 0.61 mg/m3 Range 0.01 – 76.10 mg/m3

  28. Tool: concrete mixer No.= 32 0.04 mg/m3 Range 0.01 – 0.55 mg/m3

  29. Tool: backhoe/excavator/bulldozer/bobcat No.= 28 0.01 mg/m3 Range <0.01 – 0.12 mg/m3

  30. Tool: road mill No.= 48 0.11 mg/m3 Range 0.01 – 16.10 mg/m3

  31. Environment • No.Conc. • 0.08 Open Enclosed Confined 235 0.15 15 0.33

  32. Project Type Highway N= 294 0.13 mg/m3 17% Industrial/Commercial N = 465 0.09 mg/m3 12%

  33. Huge Variability in Exposure • Half of samples were below PEL (0.1 mg/m3) • 13% of samples were over 10 times the PEL! • These extremely high exposures represented 9 of 12 tools

  34. Prioritzing for Control • Abrasive blasting and grinding • Drilling, jackhammering, and chipping • Road demolition • Concrete cutting • Clean up and cement mixing • Heavy equipment demolition

  35. Exposure Summary • Control should focus on task and tool • Degree of enclosure and type of project are also important • There is a problem – we need to move on to controlling it!

  36. Vacuum on Tools • 90% exposure reduction is possible • LEV may reduce exposures below PEL

  37. Vac

  38. Flex Grinder and Shroud Metabo Grinder Sawtec Shroud

  39. Water Control • Typically very effective • High exposures can potentially result if: - Water application rate is low and/or - Work is enclosed • Common for cutting - some other applications • Problematic in some settings

  40. Water Control • Keep spray close to the • source • Keep spray continuous • during dusty operations • Keep water reservoir filled • Maintenance needed to avoid clogging

  41. * *Based on monitoring data > 6 hours *

  42. Summary • There is a problem – we need to move on to controls! • Respirators currently used aren’t always protective enough • We need to implement other controls or controls in combination with respirators

  43. More information:http://depts.washington.edu/silica/

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