PDFWAC 296-835-12040
Control ignition sources.
(1) You must make sure the vapor areas and adjacent areas do not have any:
(a) Open flames.
(b) Spark producing devices.
(c) Heated surfaces hot enough to ignite vapors.
(2) You must use explosion-proof wiring and equipment in the vapor area.
Reference: Electrical wiring and equipment has to meet the requirements of the applicable hazardous (classified) location. See Hazardous (classified) locations, WAC 296-24-95613. Electrostatic equipment has specific electrical requirements. See WAC 296-835-13010.
(3) You must prohibit smoking in any vapor area.
Post an easily seen "NO SMOKING" sign near each dip tank.