OSHA is issuing two standards to protect workers from exposure to respirable crystalline silica—one for construction, and the other for general industry and maritime.

Currently, about 676,000 U.S. workplaces are affected by silica dust, exposing 2.3 million workers. This includes 2 million construction workers and 300,000 workers in other industries. Silicosis is fatal — according to a 2015 NIOSH study, it kills about 100 people every year.

OSHA’s Respiratory Protection Standard 29 CFR 1910.134 (f) 
Fit testing. This paragraph requires that, before an employee may be required to use any respirator with a negative or positive pressure tight-fitting facepiece, the employee must be fit tested with the same make, model, style, and size of respirator that will be used. This paragraph specifies the kinds of fit tests allowed, the procedures for conducting them, and how the results of the fit tests must be used.

OSHA’s Respiratory Protection Standard 29 CFR 1910.134 (f)(1)
The employer shall ensure that employees using a tight-fitting facepiece respirator pass an appropriate qualitative fit test (QLFT) or quantitative fit test (QNFT) as stated in this paragraph.