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  • Silicait’s one of the most common substances on earth.

  • It can be found in materials like sand and rock, and building products like concrete and brick.

  • When a worker cuts, grinds, or drills materials that contain silica, dangerous crystalline silica dust is released into the air.

  • As the worker breathes, silica crystals flow into his mouth and nose and down the air passages deep into the lungs.

  • The tiny crystals enter the small fragile air sacs where oxygen is absorbed into the blood.

  • Immune system cells called macrophages engulf and try to dissolve the crystals, but they are unable to.

  • Over time, more and more crystals build up inside the microphage cells.

  • The macrophages carry the silica into the walls of the lungwhere they die.

  • Scar tissue forms around the dead cells and spreads as more cells die.

  • This damage can continue even after the exposure to silica stops.

  • Eventually, so much scar tissue forms that the lungs can no longer function.

  • For information on how to protect yourself from silica exposure, visit

Silicait’s one of the most common substances on earth.


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B1 中級

シリカ暴露 (Silica Exposure)

  • 314 10
    kuoyumei に公開 2021 年 01 月 14 日