Except as otherwise specifically provided by law, the term "flammable liquids" shall mean all liquids having a flash point below seventy degrees Fahrenheit (70 F) as determined in accordance with the standard method of test for flash point by means of a tag closed tester (ASTM D56-56) or equivalent test device and having a vapor pressure not exceeding forty (40) pounds per square inch absolute at one hundred degrees Fahrenheit (100 F).
Okla. Stat. tit. 25, § 36