Feb 06

The new OSHA standard for crystalline silica in construction takes effect in June of 2017.  This article provides important information for employers and employees in the construction industry about the provisions of the new standard, and the required control measures necessary to minimize workers' exposures.   We can assist your company or organization with the employer obligation to comply with the standard and protect employees from silica exposures.


► Abrasive Blasting Using Silica Sand►Handling/Mixing Crushed Concrete/Asphalt
► Abrasive Blasting On Silica Substrate
► Tunnel Construction
► Sawing of Concrete/Stone► Terracotta Roofing 
► Drilling of Concrete/Stone► Ceramic Tile Installation/Removal
► Grinding of Concrete/Stone► Tuck Pointing
► Crushing of Concrete/Stone► Fiberboard Installation
► Jackhammer/Chipper Work on Concrete/Stone► Terrazzo Installation
► Milling of Concrete/Asphalt► Countertop Installation
► Hoe Ramming of Concrete/Stone► Stucco Installation/Removal
► Structure Demolition ► Paver Installation
► Refractory Installation/Repair► Block and Mortar Work
►Excavation/Grading► Silica Debris Clean-Up
►Handling/Mixing Sand► HEPA Vacuum Maintenance





On March 25, 2016, the Occupational Safety and Health Administration (OSHA) issued its final rule on exposure to crystalline silica in the workplace.  The new rule includes a standard, Respirable Crystalline Silica (29 CFR 1926.1153), that will require employers in the construction industry to ensure that their employees are not overexposed to airborne dust that contains crystalline silica.  Construction employers must comply with all requirements of the standard by June 23, 2017.  So, employers should review the standard's requirements and develop a plan of action for meeting this deadline.



The inhalation of extremely fine (respirable) particles of crystalline silica dust can cause a serious, sometimes fatal, lung disease called silicosis.  Inhaled dust can cause fibrosis (scar tissue formation) in the lungs that reduces the lungs' ability to extract oxygen from the air.  Crystalline silica exposure has also been linked to other diseases such as tuberculosis, kidney disease, and lung cancer.


The three types of silicosis:

  • Acute Silicosis: Can occur after only weeks or months of exposure to very high levels of crystalline silica.  Death can occur within months.
  • Accelerated Silicosis: Results from exposure to high levels of crystalline silica and occurs 5 to 10 years after exposure.
  • Chronic Silicosis: Usually occurs after 10 or more years of exposure to crystalline silica at low levels. This is the most common type of silicosis.


Chronic silicosis begins with few, if any, symptoms. Once present, these symptoms can include shortness of breath, severe cough, wheezing, and chest tightness, and sometimes include fever, weight loss, and night sweats. Symptoms can become worse over time, leading to death.  Once silicosis develops, it continues to progress whether further silica exposure occurs or not.


No cure for silicosis exists, but the disease is preventable. 


                                          CHEST X-RAYS


                      Normal Lungs                                 Silicosis                      



To control worker exposures to silica, measures must be taken to:

  1. prevent the generation of airborne silica-containing dust using work practices and engineering controls.
  2. prevent the inhalation of dust using respiratory protection equipment.
  3. adhere to the provisions of the new OSHA Respirable Crystalline Silica standard.



The key provisions of the new OSHA Respirable Crystalline Silica Standard are as follows:

1) Reduce the PEL for respirable crystalline silica to 50 micrograms per cubic meter (50 μg/m3) of air, averaged over an 8-hour shift.

2) Require employers to use engineering controls (such as water or ventilation) to limit worker exposure or provide respirators when engineering controls cannot limit exposure.

3) Limit worker access to high-exposure areas.

4) Develop a written exposure control plan.

5) Train workers on silica risks and measures to control exposures.

6) Provide medical exams to monitor the respiratory health of highly exposed workers.



Employers must take the following actions to determine their obligations to meet the various requirements of the OSHA standard:

  1. Identify any work or tasks their employees may perform which may create airborne dust containing crystalline silica (tasks that may produce this dust are listed at the top of this post).
  2. Determine if the employees' day-long average exposures to the dust from these tasks will be less than 25 micrograms of crystalline silica per cubic meter of air (µg/m3) under any foreseeable circumstances.  This determination can be made using any combination of air monitoring sample results or other objective data sufficient to accurately characterize employee exposures to respirable crystalline silica.   If the employee exposures are less than 25 µg/m3, no further action is required and the employer has met the obligations of the standard.
  3. If the employees' day-long average exposures may be greater than 25 µg/m3, under any foreseeable circumstances, then various exposure control methods must be implemented, including Engineering and Work Practice Control Methods, Respiratory Protection, Exposure Assessments, and Periodic Monitoring.
  4. Tasks that are typically pose an exposure potential of less than 25 μg/m3 include: mixing concrete for post holes; pouring concrete footers, slab foundations, and foundation walls; removing concrete formwork.  Most other dust producing tasks have been sufficiently evaluated to provide objective data indicating these tasks will result in crystalline silica exposures greater than the Action Level and Permissible Exposure Limit.

If the work is covered by the standard, an employer has two options for controlling employee exposure to respirable crystalline silica:

Option 1: Specified exposure control methods

Option 2: Alternative exposure control methods​

Employers who choose Option 1 (specified exposure control methods) must:

  1. Fully and properly implement the protective measures (i.e., specific engineering controls, work practices, and respirator use) for the tasks or equipment listed in Table 1 of the standard.
  2. Employers who fully and properly implement the controls in Table 1 are not required to conduct air monitoring to assess potential exposures or implement any other engineering or work practices controls for the listed tasks.


Employers who follow Option 2 (alternative exposure control methods) must:

  1. Limit employee exposures to a PEL of 50 micrograms per cubic meter of air (50 μg/m3) as an 8-hour time-weighted average (TWA).
  2. Conduct personal exposure monitoring on employees, who may reasonably be expected to be exposed to silica levels ≥ 25 μg/m3, to determine the levels of respirable crystalline silica to which they are exposed.
  3. Use engineering and work practice controls, to the extent feasible, to limit employee exposures to the PEL, and supplement the controls with respiratory protection when necessary.
  4. Maintain records of the measurements of employees' exposures to respirable crystalline silica.


All Employers covered by the standard must:

  1. Establish and implement a written exposure control plan that addresses the following:
    1. tasks that can result in silica exposure
    2. engineering controls for dust reduction
    3. work practices to be followed to minimize dust exposure
    4. description of respiratory protection, if required
    5. procedures for controlling access to work areas where high exposures might occur
  2. Designate a competent person to implement the written exposure control plan by making frequent and regular inspections of jobsites, materials, and equipment.
  3. Provide hazard communication training on the health effects of crystalline silica and the measures necessary to control exposures to silica (e.g., engineering controls, work practices, respiratory protection), recognition of hazardous tasks, and the identity of the competent person.
  4. Offer medical exams at no charge to the worker - including chest X-rays and lung function tests -initially (if not received within the last three years by another employer) and every three years, for workers who are required by the standard to wear a respirator for 30 or more days per year.
  5. Restrict certain housekeeping practices (e.g., dry sweeping, use of compressed air) that expose employees to respirable crystalline silica dust, where feasible alternatives are available.
  6. Provide respiratory protection when required.  Respirators should not be the primary method of protection.  If engineering controls cannot control dust levels below the PEL (50 μg/m3), then respirators should be used.  When respirators are used, the employer must establish a comprehensive respiratory protection program as required by the OSHA Respiratory Protection Standard [LINK TO WEB SITE].  NIOSH-approved respirators must be used. 
  7. Maintain records of medical exams, training sessions, exposure control plans, and exposure assessments.



Controlling exposures to airborne crystalline silica dust is the primary method of protecting workers from developing adverse health effects associated with silica.  If exposures cannot be controlled by eliminating or replacing the hazard, such as is typically the case with silica in construction, engineering controls should be used as the preferred control solution.  Other solutions include administrative controls and personal protective equipment (e.g., respirators), but are less preferred than engineering controls.


Engineering controls are favored over administrative and personal protective equipment for controlling worker exposures because they are designed to isolate the worker from the source of dust generation or remove the hazard at the source, before it can pose a hazard to the worker.  Well-designed engineering controls can be highly effective in protecting workers and will typically be independent of worker interactions to provide this high level of protection. The initial cost of engineering controls can be higher than the cost of administrative controls or PPE but, over the longer term, operating costs are frequently lower and, in some instances, can provide a cost savings in other areas of the process.

Two types of engineering controls are available to reduce dust exposures associated with working on silica-containing materials.  The first type of control uses water to suppress the dust, and the second type uses local exhaust ventilation and dust collector to remove and capture dust at its source.

The following table presents a list of silica dust-generating and the associated engineering controls, as specified in Table 1 of the new OSHA standard, 29 CFR 1926.1153, Respirable Crystalline Silica.  Although not shown on the table below, Table 1 of the OSHA standard also specifies requirements for respiratory protection based on task type and duration.


Stationary masonry saws​​
Saw equipped with integrated wa​ter delivery system


Handheld power saws (any size blade)
Saw equipped with integrated water delivery system that continuously feeds water to the blade

Handheld power saws for cutting fiber-cement board (with blade diameter of 8 inches or less) - outdoorsSaw equipped with commercially available dust collection system
Walk-behind saws
Saw equipped with integrated water delivery system that continuously feeds water to the blade

Drivable saws
Saw equipped with integrated water delivery system that continuously feeds water to th​e blade
Rig-mounted core saws or drills
Tool equipped with integrated water delivery system that supplies water to cutting surface​


Handheld and stand-mounted drills (including impact and rotary hammer drills)
Drill equipped with commercially available shroud or cowling with dust collection sys​tem

Dowel drilling rigs for concrete

S​hroud around drill bit with a dust collection system



Vehicle-mounted drilling rigs for rock and concrete

Dust collection system with close capture hood or shroud around drill bit with a low-flow water spray to wet the dust at the discharge point from the dust collector


Operate from within an enclosed cab and use water for dust suppression on drill bit



J​ackhammers and handheld powered chipping tools

Tool with water delivery system that supplies a continuous stream or spray of water at the point of impact


Tool equipped with commercially available shroud and dust collection system


Handheld grinders for uses other than mortar removal
​Grinder equipped with integrated water delivery system that continuously feeds water to the grinding surface


Grinder equipped with commercially available shroud and dust collection system




Walk-behind milling machines and floor grinders

Machine equipped with integrated water delivery system that continuously feeds water to the cutting surface


Machine equipped with dust collection system recommended by the manufacturer

Small drivable milling machines (less than half-lane)
Machine equipped with supplemental water sprays designed to suppress dust  Water must be combined with a surfactant
Crushing machines
Equipment designed to deliver water spray or mist for dust suppression at crusher and other points where dust is generated (e.g., hoppers, conveyers, sieves/sizing or vibrating components, and discharge points)

Heavy equipment and utility vehicles used to abrade or fracture silica-containing materials (e.g., hoe-ramming, rock ripping) or used during demolition activities involving silica-containing materials
​Operate equipment from within an enclosed cab
Heavy equipment and utility vehicles for tasks such as grading and excavating but not including: demolishing, abrading, or fracturing silica-containing material

Apply water and/or dust suppressants as necessary to minimize dust emissions


operate equipment from within an enclosed cab


HEPA-filtered vacuum



Table 1 of the OSHA standard includes additional factors and specifications that must be satisfied in order for full and proper implementation of the respective engineering control.  "Full and proper implementation" means that controls are in place, are properly operated and maintained, and employees understand how to use them. The presence of visible dust generally indicates that controls are not fully and properly implemented.



An effective respirator program as adapted from A Guide to Respiratory Protection for the Asbestos Abatement Industry, (U.S.EPA/NIOSH publication, EPA-560- OPTS86-001 September 1986) should include:

  1. A written statement of company policy, including assignment of individual responsibility, accountability, and authority for required activities of the respiratory protection program.
  2. Written standard operating procedures governing the selection and use of respirators.
  3. Respirator selection (from NIOSH/MSHA approved and certified models) on the basis of hazards to which the worker is exposed.
  4. Medical examinations of workers to determine whether or not they may be assigned an activity where negative pressure respiratory protection is required.
  5. Employee training in the proper use and limitations of respirators (as well as a way to evaluate the skill and knowledge obtained by the worker through training).
  6. Respirator fit testing.
  7. Regular cleaning and disinfecting of respirators.
  8. Routine inspection of respirators during cleaning, and at least once a month and after each use for those respirators designated for emergency use.
  9. Storage of respirators in convenient, clean, and sanitary locations.
  10. Surveillance of work area conditions and degree of employee exposure (e.g., through air monitoring).
  11. Regular inspection and evaluation of the continued effectiveness of the program.

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