Okla. Stat. tit. 40 § 174
All scaffolds, hoists, cranes, stays, ladders, supports, or other mechanical contrivances erected or constructed by any person, firm or corporation in the state, for use in the erection, repairing, alteration, removal, or painting of any house, building, bridge, viaduct, steel tank, standpipe, or other structure, shall be erected and constructed in a safe, suitable, and proper manner, and shall be so erected and constructed, placed and operated as to give proper and adequate protection to life and limb of any person or persons employed or engaged thereon, or passing under or by the same, and in such manner as to prevent the falling of any material that may be used or deposited thereon. Scaffolding or staging swung or suspended from an overhead support more than twenty (20) feet from the ground or floor, shall have, where practicable, a safety rail properly secured and braced, rising at least thirty-four (34) inches above the floor or main portion of such scaffolding or staging and extending along the entire length of the outside and ends thereto and such scaffolding or staging shall be so fastened as to prevent the same from swaying from the building or structure.
Okla. Stat. tit. 40, § 174