Silica: The Deadly Dust

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University of New Mexico Health Sciences Center , East Tennessee State University

Summary Statement

A presentation on what silica is and the illnesses that result from exposure. Includes pre and post test and questions and answers.

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Table 1. --NIOSH-recommended respiratory protection for workers exposed to respirable crystalline silica

Condition Minimum respiratory protection* required to meet the Condition NIOSH REL for crystalline silica (50 µg/m3)**
Less than or equal to 500 µg/m3 (10 x REL)*** Any air-purifying respirator with a high-efficiency particulate filter
Less than or equal to 1,250 µg/m3 (25 x REL) Any powered, air-purifying respirator with a high-efficiency particulate filter, or

Any supplied-air respirator equipped with a hood or helmet and operated in a continuous-flow mode (for example, type CE abrasive blasting respirators operated in the continuous-flow mode)
Less than or equal to 2,500 µg/m3 (50 x REL) Any air-purifying, full-facepiece respirator with a high- efficiency particulate filter, or

Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter
Less than or equal to 50,000 µg/m3 (1,000 x REL) Any supplied-air respirator equipped with a half-mask and operated in a pressure-demand or other positive-pressure mode
Less than or equal to 100,000 µg/m3 (2,000 x REL) Any supplied-air respirator equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode (for example, a type CE abrasive blasting respirator operated in a positive-pressure mode)
Planned or emergency entry into environments containing unknown concentrations or concentrations less than or equal to 500,000 µg/m3 (10,000 x REL) Any self-contained breathing apparatus equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode****, or

Any supplied-air respirator equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained breathing apparatus operated in a pressure-demand or other positive-pressure mode****
Firefighting Any self-contained breathing apparatus equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode****
Escape only Any air-purifying, full-facepiece respirator with a high- efficiency particulate filter, or

Any appropriate escape-type, self-contained breathing apparatus

 

* Only NIOSH/MSHA-approved equipment should be used.
** These recommendations are intended to protect workers from silicosis; only the most protective respirators are recommended for used with carcinogens.
*** Assigned protection factor (APF) times the NIOSH REL. The APF is the minimum anticipated level of protection provided by each type of respirator.
**** Most protective respirators

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