According to 29 CFR 1910.22(b) and 1910.176(a), OSHA simply requires permanent aisles and passageways to be appropriately marked. Here is an excerpt from a 2/14/1977 OSHA letter of interpretation: “The wording of the standard, 29 CFR 1910.22(b)(2), that aisles and passageways be appropriately marked, does not require marking by painted yellow lines only. Painted yellow lines are usually recognized as the most convenient and inexpensive way to mark aisles and passageways since the lines normally last several years without maintenance or repainting.
“Other appropriate methods such as marking pillars, powder stripping, flags, traffic cones, barrels and many other devices are considered appropriate as long as recognition of such is included in the vehicle operator and employee training programs. However, where the need exists and there are no appropriate markings, citations will be issued.”
