Respirable Crystalline Silica Exposure: Revised Regulations and Dust-Up Best Practices

After a variety of stops and starts, the revised regulations and compliance deadlines for OSHA's final rule on respirable crystalline silica exposure have finally arrived. This briefing will provide an overview of the final rule's new requirements, common control measures and dust elimination best practices.

After a variety of stops and starts, the revised regulations and compliance deadlines for OSHA's final rule on respirable crystalline silica exposure have finally arrived. This briefing will provide an overview of the final rule's new requirements, common control measures and dust elimination best practices. Information employers need to know include:

The rule installs a new Permissible Exposure Limit.

  • The final rule reduces the permissible exposure limit (PEL) to 50 micrograms of respirable crystalline silica cubic meter of air (50 g/) over an eight-hour time-weighted average (TWA).
  • The 50 g /PEL is the same for all industries.
  • The new PEL is approximately 20% of the previous PEL for the construction industry (approximately 250 g/) and 50% of the previous PEL for general/maritime industries (approximately 50 g/.)
  • The final rule also introduces an Action Level of 25 g/over an eight-hour TWA. Exposure testing is required if respirable crystalline silica exposure could be at or above the Action Level.

Exposure assessments may be necessary.

  • The final rule also introduces an action level of 25 g/over an eight-hour TWA.
  • Employers are required to conduct exposure assessments if workers exposure to respirable crystalline silica might reach or exceed the new Action Level.
  • Exposure testing measurements are used to determine what protection measures need to be put in place.

Effective October 23, 2017, Cal/OSHA is fully enforcing all appropriate provisions of the standard.Employers that are not making any efforts to comply may be considered for citation. This follows federal OSHA's approach regarding enforcement of their silica standard.

With the updated regulation, construction employers, supervisors and personnel need to be aware of:

  • Hazards of Respirable Silica Dust
  • New Requirements for Competent Persons, Silica Control Plans and Training
  • Basic and Common Control Measures

Hazards of Respirable Silica Dust

Excessive exposure to respirable crystalline silica dust can cause serious respiratory system illnesses. The most closely-related illness is Silicosis. Silicosis leads to fibrosis, the inability to breathe and in serious cases, death. Other diseases include lung cancer, kidney disease, silica dust associated tuberculosis and chronic obstructive pulmonary disease. Initially, symptoms of these illnesses may not be apparent. However, over time, shortness of breath, fatigue and ultimately severe coughing and chest pain will develop. Silicosis is incurable so taking proactive prevention measures is critical.

New Requirements for Competent Persons, Silica Control Plans and Training

A vital responsibility employers and supervisors have is to apply effective engineering controls, work practices and respiratory protection. Alternatively, they can complete task-by task assessments and then take actions to limit exposures to employees.

The new requirements outline the following measures that employers must take:

  1. Designate a Competent Person. For each job site where crystalline silica dust is generated, an employer must designate a Competent Person for silica controls;
  2. Create a written exposure control plan. The Competent Person must prepare a silica control plan which includes an identification of tasks which will involve creation of silica-containing dusts, the methods of engineering controls, work practice controls and respiratory protection which will be used for the specific tasks;
  3. Limit housekeeping practices. Reduce activities that contribute to silica exposure like dry sweeping, dry brushing and compressed air when alternatives are possible;
  4. Train workers. The employer is also required to prepare instructional training on the health hazards of crystalline silica, the contents of the silica control plan, the specific measures for control and protection to be used, the identity of the Competent Person, what a medical surveillance program for crystalline silica is and where both the regulations and measurement/testing data is kept on site.
  5. Offer employees medical surveillance exams (including chest x-rays and lung function tests) and obtain a written medical report from a licensed physician/medical professional.
  6. Keep records of medical exams and silica exposures

Control procedures are to be noted and are based on the severity of the exposure and process involved. Job hazard analysis processes should be applied to silica exposures on a task-by-task basis.

One of the most important components of these requirements is the aforementioned "Competent Person" on each project. The Competent Person is to survey the site and walk several times daily to assure compliance with the plan (task-by-task), and adjust the plan and practices as needed.This person needs be:

  • Knowledgeable about the hazards of respirable silica dust
  • Skilled at identifying work or tasks that could generate dust
  • Aware of the various means to eliminate or control the generation of dust
  • Able to provide respiratory protection for personnel
  • Skilled at documenting the list of tasks and be able to specify control or protective measures for each, and
  • Skilled at documenting the plan and be able to communicate it to supervisors and personnel

Basic and Common Control Measures

Controls are based on Cal/OSHA standards found at 8 CCR 1532.3 Table 1. Readers are reminded to refer specifically to the table itself for their activity. Job hazard analysis processes should be applied to silica exposures on a job-by-job basis.

Basic and common controls include the use of water sprays directed at the dust-generating task or work area, local exhaust ventilation with dust collectors, general ventilation, and isolating the dusty process from the operator or others and/or use of respiratory protection. It is also important to engage in all forms of housekeeping in a manner that minimizes dusts.

Examples of specific tasks and dust control measures include:

  • Concrete joint saw cutting with water
  • Transferring back fill or rock with water spray during the pickup and dumping process
  • Drilling concrete or rock with a shroud attachment around the bit with a HEPA filtered vacuum
  • Brick, block, or tile-cutting with a saw equipped with water
  • Washing down a dusty floor slab rather than dry sweeping
  • High pressure water spraying concrete surfaces rather than sand blasting

Best Practices for Dust Elimination

When possible, it's best to substitute dust-generating activities for a dust-free material or process. Substituting different materials, practices, tools, or equipment are all effective means of eliminating or reducing potential silica dust exposures. In some cases, relocating work off of the construction site to a more controlled environment can also be an effective option. An example of this process that may apply at the design stage of a project is to consider using a prefabrication process that transfers dusty work to an offsite shop with engineered controls and fewer personnel involved. Using processes and practices that eliminate or reduce the need for respiratory protection is also a best practice.

In those cases where control processes and practices do not fully eliminate the risk of dust exposures and respiratory protection must be used, added programming and practices are required. There already exist requirements for all employers who require personnel to use respirators of any type. If respirators are required, a well-documented Respiratory Protection Program, including all required activities that must be conducted. Basic elements include a documented program, medical evaluations of personnel, fit testing, provision of the gear, instruction and training, inspections, maintenance, and thorough documentation of all.

In the event personnel need to wear respiratory protection 30 or more days a year, added medical surveillance regulatory requirements now apply. The employer determines whether respiratory protection is required for 30 days or more per year. These services are free to affected employees.

Basics include:

  • Employer information is to be provided to the physician or licensed health care provider.
  • A baseline initial examination of respirator users that includes:
  • Work and medical history; past present and planned exposure to respirable crystalline silica, dust, or other agents.
  • Any history of respiratory problems, tuberculosis, smoking status and history.
  • A physical examination with emphasis on the individuals respiratory system.
  • Chest x-ray reviewed by certified reader.
  • Pulmonary function test administered by a certified technician.
  • Testing for latent Tuberculosis.
  • Added evaluation and testing where the licensed health care professional determines it is needed or appropriate.
  • Tuberculosis test repeated every 3 years.

Given the added complexity of required practices and associated costs, its useful to identify opportunities to "engineer out" dust hazards whenever possible.

In addition to this summary, Woodruff-Sawyer has available to its Construction clients the following resources:

The conduct of sound silica dust programming and practices will contribute to safer and healthier workplaces for our personnel and those around us. This must be part of our safety programming, construction management and supervisory practices. For additional information or assistance please contact your Woodruff-Sawyer account representative.

Contributing to this bulletin:

Bob Downey, RED Consulting Services (
Alan Larson, Safety Management Consulting Services (

Sources on new requirements include OSHA and AMI Environmental.


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