HAZARD ALERT
One of the most dangerous kinds of dust you can breathe is crystalline silica. Silica is the same as quartz. Silica sand is used for abrasive blasting. You get silica dust when you drill in most kinds of rock.
The Hazards
In the lungs, silica scars air sacs and keeps oxygen from getting in the blood. Silica can cause shortness of breath. And it increases your chance of getting tuberculosis (TB). Silica also causes silicosis, which can kill you. (Many industrial countries have restricted the use of silica sand for sandblasting.)
You can get silicosis after 5 to 10 years of working without breathing protection around silica dust. (You can be in danger even if you do not see dust.) Or you can get silicosis after a few weeks if you work in thick clouds of crystalline silica and you are not protected. (This happened to tunnel workers who cut through hard rock and were not protected.) Silicosis can get worse even years after you are away from the dust.
What You Can Do
• Wet down dry materials and surfaces before you work with them or before you sweep them. This will reduce some dust.
• Do not use disposable dust masks if the dust has any silica. Disposable masks do not protect you from silica. They do not form a snug seal with your face.
• For abrasive blasting, replace silica sand with safer materials. The U.S. government's National Institute for Occupational Safety and Health (NIOSH) says do not use sand or any abrasive with more than 1% crystalline silica in it. Specular hematite, crushed glass, some slags, or steel grit and shot may be good substitutes. (Use of some slags and steel grit may increase worker exposures to some toxic metals.)
• When doing abrasive blasting with any material that may contain silica, you need to use a type CE abrasive blasting respirator (positive pressure/pressure demand, with an APF of 1,000 or 2,000). This respirator provides air from outside the blasting area. Respirators must not be the main way you reduce exposures.
• When drilling in rock that may contain silica, you may need a respirator. The type of respirator you need will depend on the silica concentration levels.
• OSHA says you must have a full respiratory protection program if respirators are used. This means proper selection and fitting of respirators, medical screening of workers for fitness to wear a respirator, and worker training to use the respirators. Correct storage and cleaning of respirators and an evaluation of the program are also needed
• Do not eat, drink, or smoke near silica. Wash your hands before you eat, drink, or smoke.
• Change out of your work clothes before you go home. This limits the dust you and your family get.
• OSHA has rules about levels of silica (and other dusts). If you have questions, call your local union, CPWR — The Center for Construction Research and Training (CPWR, at 202-962-8490), NIOSH (1-800-35-NIOSH), or OSHA.
Silica is a hazard also when you dry cut masonry. Ask to see CPWR's hazard alert on Safe Work with Power Saws. (You can get hazard alerts in English or Spanish.)
© Copyright 2000, CPWR — The Center for Construction Research and Training (CPWR). CPWR is a research arm of the Building and Construction Trades Department (BCTD), AFL-CIO: CPWR, 5th floor, 111 Massachusetts Ave. NW., Washington, D.C. 20001. (Edward C. Sullivan is president of the BCTD and of CPWR.) Production of this card was supported by grants UO2/CCU310982 and UO2/CCU312014 from the National Institute for Occupational Safety and Health (NIOSH). The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.
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