Section 296-307-45015. Take additional precautions if you recirculate ventilation system exhaust air into the workplace.

You must:

• Only recirculate air that contains no substance at a concentration that could pose a health or safety hazard to employees

• Make sure any exhaust system that recirculates air into the workplace:

– Passes the air through a device that removes contaminants

– Sounds an alarm and automatically shuts down the dip tank operation, if the vapor concentration of any substance in the exhaust air exceeds twenty-five percent of its LFL

– Monitors the concentration of vapor from flammable or combustible liquids with approved equipment.

Note:	• The LFL concentration in the air must be determined after the air passes through the air-cleaning device and before the air reenters the workspace
	• Most substances will pose a health hazard at a concentration far below twenty-five percent of its LFL.

[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, and 49.17.060. WSR 03-10-068, § 296-307-45015, filed 5/6/03, effective 8/1/03; WSR 97-09-013, recodified as § 296-307-45015, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. WSR 96-22-048, § 296-306A-45015, filed 10/31/96, effective 12/1/96.]

RCW 49.17.010, 49.17.040, 49.17.050, and 49.17.060. WSR 03-10-068, § 296-307-45015, filed 5/6/03, effective 8/1/03; WSR 97-09-013, recodified as § 296-307-45015, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. WSR 96-22-048, § 296-306A-45015, filed 10/31/96, effective 12/1/96.