While as scientists we all love to investigate those little nuances of flash point vs concentration curves, etc, the real crux is what Erika only touched on -- INSURERS!!! It has been my experience in industry that an insurer does not care what the concentration of a flammable solvent is in water (or any toxic as0far-as that goes) only that you are using a flammable solvent. Therefore prepare for the worst case scenario. Lynn K ________________________________________________________________________ Interested in getting caught up on today's news? Click here to checkout USA TODAY Headlines. http://track.juno.com/s/lc?s=198954&u=http://www.usatoday.com/news/front.htm?csp=24