Wash. Admin. Code § 296-880-40075
Crawling boards, chicken ladders, and their use must conform with the following provisions: Crawling boards and chicken ladders are not fall protection systems.
(1) Crawling boards must be not less than ten inches wide and one inch thick, having cleats one by one and one-half inches:
[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060, and chapter 49.17 RCW. WSR 20-12-091, § 296-880-40075, filed 6/2/20, effective 10/1/20.]