Powered by GoogleTranslate
Standard Interpretations - Table of Contents
• Standard Number: 1910.134(a)(1); 1910.134(a)(2)

May 12, 1999

Mr. David Koch
Senior Technical Service Specialist
P.O. Box 622
Reading, PA 19603-0622

Dear. Mr. Koch:

This letter is in response to your March 24, request for clarification of the Occupational Safety and Health Administration's (OSHA's) respiratory protection requirement for employees exposed to crystalline silica. Thank you for your inquiry.

According to 29 CFR 1910.134(a)(1), respiratory protection must be used "in the control of those occupational diseases caused by breathing air contaminated with harmful dusts, fumes, fogs, gases, smokes, sprays, mists, or vapors." Inhaling crystalline silica dust is correlated with the development of silicosis, pneumoconiosis, and other lung diseases. 29 CFR 1910.134(a)(2) states that "Respirators shall be provided by the employer when such equipment is necessary to protect the health of the employee." When engineering controls such as enclosures or ventilation are not feasible, or while such controls are being implemented, respirators must be used to reduce workers' occupational exposure to airborne contaminants.

Because each worker's environment is different, and the amount of occupational exposure to crystalline silica dust varies, an occupational exposure determination should be completed before selecting an appropriate respirator. The minimum respiratory protection for a worker who is working with crystalline silica dust, but is not doing abrasive-blasting, may be an N95 NIOSH-approved respirator. However, the exposure to crystalline silica must not exceed the assigned protection factor of the respirator.

We appreciate the opportunity to provide you with this information. If you require further assistance, please do not hesitate to contact OSHA's Office of Health Compliance Assistance at 202-693-2190.


Richard E. Fairfax
Directorate of Compliance Programs

Standard Interpretations - Table of Contents

Thank You for Visiting Our Website

You are exiting the Department of Labor's Web server.

The Department of Labor does not endorse, takes no responsibility for, and exercises no control over the linked organization or its views, or contents, nor does it vouch for the accuracy or accessibility of the information contained on the destination server. The Department of Labor also cannot authorize the use of copyrighted materials contained in linked Web sites. Users must request such authorization from the sponsor of the linked Web site. Thank you for visiting our site. Please click the button below to continue.