Wash. Admin. Code § 296-809-60004
(2) Before entry, eliminate any unsafe conditions including removing an entrance cover.
When entrance covers are removed, promptly guard the opening with a railing, temporary cover, or other temporary barrier to prevent any accidental falls through the opening and protect entrants from objects falling into the space.
(3) For spaces with potential atmospheric hazards you must do all of the following:
(a) Test before an employee enters the confined space. Use a calibrated, direct-reading instrument to test the internal atmosphere for all of the following, in this order:
(c) Use continuous forced air ventilation, as follows:
(5) Evacuate employees from the space immediately when any of the following occurs:
(6) When a space is evacuated, it cannot be reentered as alternative methods unless you do all of the following:
[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060 and chapter 49.17 RCW. WSR 18-02-071, § 296-809-60004, filed 1/2/18, effective 2/5/18. Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060. WSR 15-24-102, § 296-809-60004, filed 12/1/15, effective 1/5/16; WSR 04-03-081, § 296-809-60004, filed 1/20/04, effective 5/1/04.]