OSHA Respirable Crystalline Silica Standard – Construction Enforcement Date Extended

TUESDAY, MAY 16, 2017

By Thomas Carroll, CS Unitec, Inc.

Recently, OSHA extended the Respirable Crystalline Silica enforcement deadline for general construction by three months to September 23, 2017. OSHA issued the extension to “conduct additional outreach and provide educational materials and guidance for employers.” Even though the compliance date has been moved out, it is still important for employers to continue making preparations and plans to capture, contain and suppress inhalable crystalline silica.

Crystalline silica is often present on job sites — in both naturally occurring stone and sand, as well as in man-made materials such as concrete, cement and mortar. Crystalline silica has been cited as a major health hazard — designated a known human carcinogen — in construction and industry when it is in dust form, causing illnesses and potentially fatal conditions such as silicosis, tuberculosis, COPD, kidney disease and lung cancer.

Dust collection systems with HEPA-certified filtration are one way to meet OSHA's new Respirable Crystalline Silica Standard.

Danger to the worker arises when the silica becomes airborne, through cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and mortar materials. According to OSHA, approximately 2.3 million workers are exposed to crystalline silica on the job, and this regulation is predicted to affect approximately 676,000 construction, general industry and maritime workplaces.

For construction, the 2017 regulation reduces the permissible exposure limit (PEL) of respirable crystalline silica to workers by 80 percent of the previous maximum. For general industry and maritime workers, there is a reduction to 50 percent of the previous maximum. The PEL for respirable crystalline silica over an 8-hour shift will be 50 micrograms per cubic meter of air.

The “rulebook” for this standard is OSHA’s Table 1: Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica. This table outlines 18 common actions performed on job sites with regard to silica-containing materials. If employers implement the engineering and work practice control methods, as well as the required respiratory protection related to each equipment/task in the table, they will not be obligated to have job-site air samples analyzed by a third-party testing laboratory and reviewed by OSHA.

Peening preparation tools, or hand-held scarifiers, with a shroud and connected to an industrial vacuum, are ideal alternatives to small-area shot blasting.

In their FAQ document, OSHA points out that while respirators for everyone, all the time, might sound like a good idea, they would not protect workers as well as the outlined engineering and work practice control methods. Workers wearing respirators only, without the job-site control methods, would still be exposed to silica. Further, respirators are not as practical as they might seem. It is not realistic for every worker to have a personal respirator that is individually fitted, periodically refitted and regularly maintained. According to OSHA, “Respirators are only allowed when engineering and work practice controls cannot maintain exposures at or below the PEL.”

Table 1 includes guidance when using a wide variety of hand-held and walk-behind power tools, including masonry saws, fiber-cement saws, concrete core drills, rotary hammer drills, grinders, power scabbling, scarifying, scaling and chipping tools, and more. Broken down into an exposure time of less than and greater than a 4-hour shift, the table outlines the control methods for each tool, as well as the minimal respiratory protection for each shift length.

Two main methods of controlling silica dust with hand-held and walk-behind tools are dust collection and dust suppression. Dust collection with a vacuum connected to the power tool is a common system used to capture the dust at the source. OSHA requires a vacuum with a “high-efficiency particulate air (HEPA) filter… that is at least 99.97-percent efficient in removing mono-dispersed particles of 0.3 micrometers in diameter.” The organization also requires that the vacuum include an integrated filter cleaning mechanism. Many power tools are available with a dust shroud or cowl to better control and guide dust into the vacuum hose; and they are recommended by OSHA. Some HEPA-certified vacuums will power the tool on and off, as well as run for an additional period of time to clean the hose of any lingering dust.

Floor scarifier (left) with an integrated vacuum connection removies coatings and residue from a concrete floor prior to resurfacing. (Right) Scabbling concrete can create potentially hazardous airborne silica dust and debris if a dust shroud and HEPA-certified dust collection vacuum are not used during operation.

Dust suppression applies to both the use of a tool and the clean-up of any remaining dust on the job site. For cutting or impact-type tools, OSHA recommends (when available) choosing a tool “with a water delivery system that supplies a continuous stream or spray of water” at the point of cutting or impact. This will contain the dust in a slurry that can be collected. Similarly, when cleaning silica-containing areas, wetting the dust down will create an easily collected slurry. Compressed air or dry brushes should never be used, as they will send any remaining silica dust airborne.

Even though OSHA has delayed enforcement of this regulation, it is important that employers continue to prepare to meet or exceed the Occupational Exposure to Respirable Crystalline Silica regulation. In addition to the fact that following the regulation is a rule of law, our job-site employees are our greatest asset. We owe it to them to ensure their safety in the workplace. 

For more information on the OSHA Respirable Crystalline Silica Rule, including methods to assist in moving your job sites and employees toward compliance, download our white paper now.

OSHA regulations are subject to change. Visit www.osha.gov/silica for up-to-date details.

For reference, The Center for Construction Research and Training has put together a helpful “Create-A-Plan to Control the Dust” program that will walk contractors and other job-site safety personnel through the steps to create a written exposure control plan and protect workers employed in silica dust-creating job sites.


  1. FAQ: Respirable Crystalline Silica Rule, https://www.osha.gov/silica/Silica_FAQs_2016-3-22.pdf
  2. OSHA Silica Site, https://www.osha.gov/silica/

*Claims or positions expressed by sponsoring authors do not necessarily reflect the views of TPC, PaintSquare or its editors.

Thomas Carroll, CS Unitec, Inc.

Tom Carroll is president of CS Unitec, Inc., located in Norwalk, Connecticut. He has over 40 years of experience with electric, pneumatic and hydraulic power tools. In 1990, he founded the company to bring high-quality power tools to the construction, manufacturing and marine industries in the North and South American markets. CS Unitec’s heavy-duty power tools and equipment are built with a focus on innovation and user safety.