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S I L I C A

S I L I C A. HAZARDS & CONTROLS. What are the hazards associated with exposure to silica dust, as well as basic preventive and control measures. Each year more than one million miners and other workers are exposed to dangerous levels of the dust - SILICA. SILICOSIS HIGH RISK JOBS.

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S I L I C A

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  1. S I L I C A HAZARDS & CONTROLS

  2. What are the hazards associated with exposure to silica dust, as well as basic preventive and control measures

  3. Each year more than one million miners and other workers are exposed to dangerous levels of the dust - SILICA

  4. SILICOSISHIGH RISK JOBS DRILLERS CRUSHER OPERATORS BINSETTERS QUALITY CONTROL TECH SANDBLASTERS PLANT HELPERS MAINTENANCE PERSONNEL MOBILE EQUIP. OPERATORS (without environmental cabs) CHANGING SCREENS, BAG REPLACEMENT, BAGGING (without environmental booths) CONFINED SPACE ENTRY

  5. Where’s it come from? Silica (Silicon Dioxide or SiO2) is found mainly as quartz in nearly all mineral deposits. It is found in common rocks such as granite, sandstone, limestone, and is the principle component of sand.

  6. Crystalline Silica • Quartz • Cristobalite • Tridymite

  7. What Are Dusts? • Solid particles suspended in air • Generated by blasting, drilling, crushing, grinding, etc.

  8. The Body Defends Against Dust By: • Trapping larger particles in the nasal passages, throat, trachea, larynx • Trapping particles in mucous and carrying them up the airways where they are coughed out or swallowed (mucociliary escalator)

  9. Silica dustmay be a hazard, if... • it is in the respirablerange: small enough to get into the air sacs (alveoli) ----basically less than 10 microns in size • it is present in high enough concentrations bronchiole alveoli

  10. How Does Silica Affect The Body? • Silica particles build up in the lungs leading to a type of dust disease (pneumoconiosis) called silicosis • Makes affected workers more susceptible to TB • Causes cancer

  11. Silicosis : Severity ofDisease • Depends on: • Dust Concentration • Percent of free silica • Duration of exposure • Size of particles (respirable??)

  12. ChronicSilicosis • Most common form • Occurs after 20 - 45 years of exposure • Inhaled dust causes scarring • After years of exposure - massive fibrosis (scarring)

  13. AcceleratedSilicosis • Develops 5 - 10 years after start of exposure • May lead to massive fibrosis and death

  14. Acute Silicosis • Occurs where silica concentrations are very high • Can cause symptoms within a few weeks to 4 or 5 years • Rapidly FATAL

  15. WARNING!! Even when affected workers are removed from exposure, silicosis may continue to progress

  16. Development of Silicosis is: • More Likely With: • Inadequate dust control measures • Inadequate respiratory protection • Lack of medical screening • Lack of air monitoring

  17. Medical Exams Include: • Medical and work history • Checkup to detect early signs of lung disease • Chest x-ray (reviewed by “B” reader) • Breathing test • TB examination

  18. Mine Operators Must Report • Silicosis cases for which award of compensation or medical diagnosis is received by miner

  19. Evaluate Worker Exposures By: • Doing work area inspections • Sampling, monitoring workers • Observing work practices

  20. Monitoring: Personal Exposures

  21. PERMISSIBLE EXPOSURE LIMIT (PEL) PEL = 10 mg / m 3 % Quartz + 2

  22. REDUCESilica Exposures: • Assess potential for exposure • Use engineering controls, such as: • Dust Collectors • Environmental cabs and booths • Water Sprays • HEPA Filters and Vacuum (Don’t cleanup with brooms/shovels)

  23. THE END !

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