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Silica Dust at a Glance: Answers to 7 FAQ About OSHA’s New Rule

August 18, 2016

Updated in April 2017, to reflect a 3-month delay in the enforcement of the rule for the construction industry.

In March of this year, OSHA announced a new final rule to protect workers exposed to silica dust. As this is the first time silica regulations have been updated since 1971, the new ruling has thrown many industries for a loop.

For companies just starting to wade through the regulations and make compliance plans, this article provides answers to seven questions about silica dust and the new rule.

1. What exactly is silica dust?

Silica is the same as silicon dioxide, the second most abundant element in the Earth’s crust (after oxygen). Silica can be both crystalline and non-crystalline. Crystalline silica comes in several forms, the most abundant of which is quartz. Crystalline silica is found in brick, concrete, mortar, drywall, and other construction materials, as well as in asphalt, glass, topsoil, and more.

Particles of crystalline silica that are small enough to be respirable (i.e., taken in by breathing) is called silica dust.

2. What health problems does silica dust cause?

Breathing silica dust is associated with lung cancer, chronic obstructive pulmonary disease (COPD), kidney disease, and silicosis.

Silicosis is a disease in which the lungs become scarred, making it difficult to breathe. The symptoms of silicosis appear anywhere from a few weeks to many years after exposure to silica dust, and typically worsen over time.

The most common type of silicosis in the United States today is chronic silicosis, which is caused by consistent low-level exposure to silica dust for more than 10 years. Silicosis is fatal — according to a 2015 NIOSH study, it kills about 100 people every year.

3. Where is silica dust found in industry and how many workers are exposed?

Currently, about 676,000 U.S. workplaces are affected by silica dust, exposing 2.3 million workers. This includes 2 million construction workers and 300,000 workers in other industries.

Here are some examples of construction activities that put workers at risk:

  • Abrasive blasting
  • Rock-crushing
  • Jackhammering and impact drilling
  • Underground construction work
  • Drywall finishing
  • Tuck-pointing and grinding

And a few of the industries outside of construction where silica dust may be present:

  • Hydraulic fracturing
  • Dental laboratories
  • Iron foundries
  • Jewelry
  • Pottery
  • Railroads
  • Shipyards

4. How much silica dust can workers be exposed to under the new rule?

The new rule significantly reduces the permissible exposure limit (PEL) for crystalline silica. The new PEL is 50 micrograms of respirable crystalline silica per cubic meter of air, averaged over an eight-hour day. The air employees breathe must be regularly sampled and analyzed to ensure they aren’t being exposed above this level.*

The new PEL is half the previous limit for general industry and maritime and five times lower than the previous limit for the construction industry. OSHA estimates that the new rule will save more than 600 lives and prevent more than 900 new cases of silicosis each year.

*In the construction industry, if employers abide by the engineering and respirator controls in Table 1, they don’t have to sample or analyze the air.

5. How can employers reduce silica dust exposure among their employees?

OSHA outlines five ways employers can ensure their employees’ PEL is below the limit:

  • Implementing engineering controls and safe work practices. This includes wet methods, ventilation, and general housekeeping procedures.
  • Providing respiratory protection. Respiratory protection can be used only when engineering controls are insufficient to reduce exposure below the PEL.
  • Limiting access to high-exposure areas. Employers must designate areas where exposure could be above the PEL as “regulated areas.”
  • Training. Employers must train workers on what operations can expose them to silica dust and on proper work practices to limit that exposure.
  • Providing medical exams to highly exposed workers. Any worker exposed over 25 micrograms per cubic meter for 30 days per year (aka the “action level”) must be put under medical surveillance. (See the table below for more information about the medical exam requirement.)

Employers must provide a written control plan documenting how they will achieve compliance with the standard.

6. What housekeeping methods are approved for dust removal?

One of the most effective ways of reducing exposure to silica dust in many environments is by implementing a general housekeeping program. The basic rule of thumb when it comes to housekeeping is to avoid any method that could cause dust to disperse into the air.

  • Approved housekeeping methods
    • Wet methods (i.e., using water to keep the dust down)
    • Vacuums that meet strict filter requirements
  • Prohibited housekeeping methods (unless approved methods are not feasible):
    • Compressed air
    • Dry brushing
    • Dry sweeping

7. When do employers need to comply with the new rule?

The rule went into effect on June 23, 2016. The compliance dates will roll out over the next five years.

Construction Industry

Comply with all obligations of the standard, except methods of sample analysis September 23, 2017
Comply with methods of sample analysis June 23, 2018

General Industry and Maritime

Comply with all obligations of the standard, except the action level trigger for medical surveillance June 23, 2018
Offer medical examinations to employees exposed above the PEL for 30 or more days a year June 23, 2018
Offer medical examinations to employees exposed at or above the action level for 30 or more days a year June 23, 2020

Hydraulic Fracturing

Comply with the engineering controls of the standard June 23, 2021

Over the next several weeks, we’ll be publishing additional articles to help you navigate OSHA’s new silica dust rule. Sign up for our newsletter at the top right of this page to stay in the know.

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