Emergency Temp Rule Aims to Protect Workers Handling Artificial Stone

Mel Davis

What is Cal/OSHA doing for workers who deal with manufactured artificial stone?

On December 14, 2023, the Occupational Safety and Health Standards Board adopted an Emergency Temporary Standard (ETS) for Section 5204 of the General Industry Safety Orders (GISO) relating to respirable crystalline silica (RCS). This regulation went into effect on December 29, 2023.

GISO Section 5204 originally was developed using medical information and case histories of employees who contracted silicosis in traditional industries such as mining, quarrying, and sandblasting where natural rock was the contributing factor.

With the introduction of manufactured artificial stone, Section 5204 is not well-suited for application to small businesses and working conditions of the stone fabrication industry.

Natural stone may have up to 43% silica, whereas manufactured artificial stone contains approximately 93% crystalline silica, in addition to adhesives and other additives.

Section 5204, as written before the present revision and adoption of the ETS, did not have the provisions necessary to prevent or mitigate a serious, rapid increase in silicosis cases. As a result, the incidence of silicosis within the stone fabrication industry is well past a statistical normal.

Cal/OSHA reports that from July 2023 to November 2023, known cases of silicosis increased from 52 to 93. The requirements of existing Section 5204 were not adequate to provide a safe working environment. Important revisions will protect workers engaged in high-exposure trigger tasks — such as cutting, grinding, polishing, clean-up, etc. — involving artificial stone and natural stone containing more than 10% crystalline silica.


As stated earlier, the regulation addresses the manufacture or fabrication of artificial stone. It does not apply to:

  • Construction work covered under Section 1532.3.
  • Agricultural operations covered under Section 3436.
  • Exposures that result from the processing of sorptive clays.

Recommended Precautions

The regulation requires that dust control be implemented and recommends methods to accomplish the desired result:

  • Apply continuous, appropriate volumes of water.
  • Submerse the work under water.
  • Water jet cutting.

The emergency rule also calls for workers to perform designated tasks in clearly identified areas. Employers must post warning signs, printed in both English and Spanish.

Employers also should ensure cleaning is performed using methods that prevent dust from developing.

Written Plan

The written exposure control plan is to include:

  • Air monitoring records showing that engineering controls are effective.
  • Procedures for the proper use of personal protective equipment.
  • Documentation of proper reporting of carcinogen use to Cal/OSHA as required by Section 3203.
  • Training procedures to ensure employees can prevent RCS exposures.

The emergency rule stresses communication and training requirements for employees with emphasis on the following:

  • How to use the required dust control methods, including work practices and respirator protection to prevent dust exposures.
  • The health hazards and symptoms of excessive RCS airborne exposures, such as cough, difficulty breathing, fatigue, shortness of breath, weakness, fever, chest pain, or unexpected weight loss — including how crystalline silica dust can worsen the effects of smoking and tuberculosis.
  • Employees are encouraged to seek medical attention if they think they are experiencing RCS airborne exposure-related symptoms. Early diagnosis and treatment is important.


Respirator protection as required by Section 5144 will be exercised and organic vapor cartridges will be used unless the employer can demonstrate there is no exposure to organic compounds from the artificial stone that exceeds the permissive exposure limit.

A loose-fitting powered air-purifying respirator (PAPR), nonpowered full-facepiece air-purifying respirator, or an equally protective alternative may be permitted if the employer demonstrates exposures are below the action level through air monitoring every six months or otherwise recommended by a health care professional.

The employer is to conduct employee airborne exposure monitoring at least every 12 months.

More Information

To see the complete revision, go to www.dir.ca.gov/dosh/respiratory-silica-FAQ.html. Included on this page are links to Cal/OSHA fact sheets for employers and employees, and a model written silica exposure control plan for general industry.

To see the final approved text of the emergency temporary regulation, visit www.dir.ca.gov/OSHSB/documents/Respirable-Crystalline-Silica-Emergency-apprvdtxt.pdf.

Column based on questions asked by callers on the Labor Law Helpline, a service to California Chamber of Commerce preferred members and above. For expert explanations of labor laws and Cal/OSHA regulations, not legal counsel for specific situations, call (800) 348-2262 or submit your question at www.hrcalifornia.com.

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Mel Davis joined the CalChamber in 2000 as a workplace safety expert specializing in Cal/OSHA and safety-related matters. He worked for Cal/OSHA for more than 23 years as a principal safety engineer and construction safety engineer. His responsibilities included managing the technical staff responsible for developing and revising California safety and health regulations, evaluating requests for variances from regulations, and conducting complaint and accident investigations at all types of construction sites.