How does respirator use compare with engineering/work practice controls with working around silica?

Under the hierarchy of controls, respirators can be another effective way to protect employees. However, respirators may be less practical or effective than engineering controls for the following reasons:

• They must be selected for each worker, fitted, occasionally refitted, and regularly maintained (including replacing filters and other parts as necessary);
• Employees must consistently and correctly use properly fitted respirators but may resist wearing them because respirators can be uncomfortable, especially in hot weather;
• Respirators may put a physical strain on employees’ bodies, because of the respirator’s weight and because they increase breathing resistance. Employees with some health conditions cannot wear respirators because the physical strain of wearing the respirator increases their risk of illness, injury, and even death;
• Respirators can create safety concerns because they interfere with workers’ ability to hear, see, smell, and communicate; and
• Respirators only protect the employees wearing them.

Employers must provide respiratory protection:

• Where exposures exceed the PEL during periods necessary to install or implement feasible engineering and work practice controls;
• Where exposures exceed the PEL during tasks, such as some maintenance and repair tasks, for which engineering and work practice controls are not feasible;
• During tasks in which the employer has implemented all feasible engineering and work practice controls but exposures remain above the PEL; and
• While the employee is in a regulated area.

Where respirator use is required, employers must implement a respiratory protection program, which ensures respirators are properly used in the workplace and are effective in protecting employees. The respirators must comply with requirements of the silica standard and with OSHA’s Respiratory Protection standard (29 CFR 1910.134).

Even when engineering and work practice controls cannot reduce exposure levels to or below the PEL, those controls must be used to reduce exposures as low as possible. This reduction in exposure levels benefits employees by reducing the required protection factor of the respirator, and thus increasing the choices of respirators that can be used.

For example, if feasible engineering controls reduce exposures from 50 times to less than 10 times the PEL, employers could provide approved half-mask respirators with an Assigned Protection Factor (APF) of 10 that may be lighter and easier to use compared to full-facepiece respirators.