The simple answer is: often enough to cause concern. Because the process of changing the legal code is so complicated, these changes don’t come according to a regular schedule—but when they do, they can cause serious waves in the manufacturing sector.
When OSHA changes a regulation, it sets a timetable for implementation, explains how it will be enforced and so on. The agency will typically allow months—if not years—for employers to adjust to the new rule. While this may sound generous, if a change in regulation is significant enough, it will likely require quick and serious action from an employer.
A good example of such a change came in 2016 when OSHA changed its regulation of crystalline silica. The agency determined that the existing permissible exposure limit (PEL) for the substance was not adequately protecting workers and cut the limit in half. Manufacturers are still scrambling to adapt to the change.