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Frequently Asked Questions

What is silica?

When is silica a hazard for construction workers?

What construction materials contain silica?

How much silica dust is too much?

What illnesses can result from breathing in dust that contains silica?

What is silicosis?

I don’t know anyone with silicosis so why should I be worried?

How many people are diagnosed with silicosis each year?

How should I avoid bringing dust home on my clothes?

What should employers do to protect their employees?

How do I prevent exposures and control the dust?

What can I do to protect myself?

Where can I find out about silica related rules and regulations?

Where can I find help in my area on silica?



  1. What is silica?
    Silica is one of the most common naturally occurring elements on the planet. Silica, the mineral compound silicon dioxide (SiO2), is found in two forms -- crystalline or noncrystalline (also referred to as amorphous). Sand and quartz are common examples of crystalline silica.

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  2. When is silica a hazard for construction workers?
    Materials that contain crystalline silica are not hazardous unless they are disturbed, generating small-sized particles that can get in your lungs (“respirable crystalline silica”).  For example, blasting, cutting, chipping, drilling and grinding materials that contain silica can result in silica dust that is hazardous for construction workers and others to breathe. For a list of construction materials that contain silica go to the “Know the Hazard” section of this website.

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  3. What construction materials contain silica?
    Many common construction materials contain silica including, for example, asphalt, brick, cement, concrete, drywall, grout, mortar, stone, sand, and tile.  A more complete list of building materials that contain silica, as well as information on how to find out if the material you’re working with contains silica, can be found in Step 1 of the Create-A-Plan section of the website.

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  4. How much silica dust is too much?
    It only takes a very small amount of the very fine respirable silica dust to create a health hazard.  Recognizing that very small, respirable silica particles are hazardous, OSHA regulation 29 CFR 1926.55(a) requires construction employers to keep worker exposures at or below a Permissible Exposure Level (PEL) of 0.1 mg/m3.  The National Institute for Occupational Safety and Health has a lower Recommended Exposure Level of 0.05 mg/m3.  More information about the hazard and links to examples of exposures with and without controls compared to the OSHA PEL, can be found at "Know the Hazard? Why is Silica Hazardous?".

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  5. What illnesses can result from breathing in dust that contains silica?
    Inhaling crystalline silica can lead to serious, sometimes fatal illnesses including silicosis, lung cancer, tuberculosis (in those with silicosis), and chronic obstructive pulmonary disease (COPD). In addition, silica exposure has been linked to other illnesses including renal disease and other cancers. In 1996 the World Health Organization – International Agency on Cancer Research (IARC) identified crystalline silica as a “known human carcinogen” (they reaffirmed this position in 2009).  The American Thoracic Society and the American College of Occupational and Environmental Medicine have also recognized the adverse health effects of exposure to crystalline silica, including lung cancer.

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  6. What is silicosis?
    Silicosis is a disabling, irreversible, and sometimes fatal lung disease. When a worker inhales crystalline silica, the lungs react by developing hard nodules and scarring around the trapped silica particles. If the nodules become too large, breathing becomes difficult and death can result. The risk of silicosis is high for workers in several industries, including the construction industry, according to the Center for Disease Control (CDC), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA).

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  7. I don’t know anyone with silicosis so why should I be worried?
    Unlike a work-related injury where the effects are seen immediately, silicosis and other silica-related illnesses may not show up for many years after exposure.  The most common early symptoms are a chronic dry cough and shortness of breath with physical activity. There are three types of silicosis:
    • Chronic silicosis, which usually occurs after 10 or more years of exposure to crystalline silica at relatively low concentrations;
    • Accelerated silicosis, which results from exposure to high concentrations of crystalline silica and develops 5 to 10 years after the initial exposure; and
    • Acute silicosis, which occurs where exposure concentrations are the highest and can cause symptoms to develop within a few weeks to 4 or 5 years after the initial exposure.
    Silicosis is a progressive disease – meaning it continues to get worse, even when exposure to respirable silica has stopped.

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  8. How many people are diagnosed with silicosis each year?
    Millions of workers are exposed to dust containing silica.  A recent study, Estimating the Total Number of Newly-Recognized Silicosis Cases in the U.S., determined that between 3,600 to 7,300 new cases of silicosis occur annually in the United States.  However, only two of the 50 states, New Jersey and Michigan, have surveillance programs to track cases of silicosis.  As a result, many cases of silicosis are not reported and many more are not properly diagnosed. One study, Previously Undetected Silicosis in New Jersey Decedents, which reviewed the chest x-rays of individuals exposed to silica dust during their life-time, found evidence of silicosis that had not been diagnosed.

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  9. How should I avoid bringing dust home on my clothes?
    The National Institute for Occupational Safety (NIOSH) recommends that workers avoid bringing silica dust home from work by:
    • Changing into disposable or washable work clothes at the worksite.
    • Showering (if possible) and changing into clean clothes before leaving the worksite to prevent contamination of other work areas, cars, and homes.
    • Parking your car where it will not be contaminated with silica.

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  10. What should employers do to protect their employees?
    Planning is key to reducing exposures and protecting workers. Before work begins, an employer should create a job-specific plan that identifies the materials and tasks that could expose workers to silica dust, the equipment and controls that will be used to control the dust and prevent exposures, and the employee onsite who will make sure the silica plan is followed.  In addition, the employer should train all employees – workers and supervisors – on the information in the plan, including how to identify a silica hazard, proper use and maintenance of equipment and controls, and the importance of using the personal protective equipment provided.  This website includes several resources to help employers develop silica control plans for their jobs and train their workers.  The “Create-A-Plan” tool walks an employer through 3 critical planning steps and generates a silica control plan that can be printed, emailed, or saved.  In addition, the “Training and Other Resources” section includes silica-related instructional materials, toolbox talks, handouts, videos, and other resources employers can use to train their employees.  Note:  the Silica Control Plan generated by using the “Create-A-Plan” tool can also be presented as a toolbox talk.

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  11. How do I prevent exposures and control the dust?
    Preventing the dust from becoming airborne is a good way to reduce exposures.  Water can be used to suppress the dust and vacuums can be used to capture it at the source. When water or vacuums are not feasible, or if the exposures are still high even with these controls, a NIOSH approved respirator should be used; however, respirators won’t  protect those working close by.  Other ways to reduce or eliminate exposures include using different materials, such as aluminum oxide instead of sand for abrasive blasting, or using work practices that help minimize dust. The “Create-A-Plan” tool on this website provides examples by material and task for controlling dust.


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  12. What can I do to protect myself?
    It is your employer’s responsibility by law to provide a safe workplace.  This is an OSHA requirement.  However, it is a worker’s responsibility to use the equipment provided, participate in educational programs on silica, and follow his or her employer’s safety and health instructions.  NIOSH recommends that workers:
    • Become informed of the health effects of breathing silica dust and the tasks that generate this dust on the job.
    • Reduce their exposure by avoiding working in dust whenever possible, using controls provide, and wearing a respirator when needed.
    • Take advantage of health or lung screening programs offered.
    • Use good personal hygiene at work:
      • Do not eat, drink, or use tobacco products in dusty areas.
      • Wash hands and face before eating, drinking, or smoking outside dusty areas.
      • Change into disposable or washable work clothes at the worksite.
      • Shower (if possible) and change into clean clothes before leaving the worksite to prevent contamination of other work areas, cars, and homes.
      • Park cars where they will not be contaminated with silica.
    To learn more read “Silicosis: Learn the Facts!”


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  13. Where can I find out about silica related rules and regulations?
    OSHA is the primary source for information on regulations that cover silica exposures and measures employers are required to take to protect their employees. To learn more go to OSHA Silica Related Standards for Construction

    In addition, New Jersey and California have state-level silica requirements and several cities have ordinances to protect the public from dust: NJ Cutting and Grinding of Masonry Regulation; California regulation.

    The Regulations & Requirements section of this website contains information on these and other efforts related to silica.


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  14. Where can I find help in my area on silica?
    OSHA offers free and confidential advice to small and medium-sized business through an On-site Consultation Program. According to OSHA, the “On-site Consultation services are separate from enforcement and do not result in penalties or citations. Consultants from state agencies or universities work with employers to identify workplace hazards, provide advice on compliance with OSHA standards, and assist in establishing safety and health management systems.”  To learn more visit OSHA On-Site Consultation


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