In general, employers must provide fall protection to construction workers working on surfaces with unprotected sides and edges that are how many feet above the lower level?

Historically, falls are the leading cause of fatalities in construction, accounting for about one-third of all fatalities in the industry. OSHA recognizes that incidents involving falls are generally complex events, frequently involving a variety of factors. The standard for fall protection relates to the human and equipment-related issues to protect workers. The 6-foot rule means that for workers working at heights of 6 feet or greater above a lower level. This applies at heights of less than 6 feet when working near dangerous equipment, for example, working on machinery with open drive belts, pulleys or gears or open vats of degreasing agents or acid.

I'm not 100% sure but i think it is service producing industries