A combustible liquid is defined as, “Any liquid that has a closed-cup flash
point at or above 100 degrees F (37.8 degrees C) as determined by the test
procedures and apparatus set forth in section 4.4”. It is important to note
that there is no upper boundary on this definition. Liquids with flash points at
600 or 800 degrees F would still be considered combustible liquids. In fact
canola oil, which has a flash point of about 620 degrees F is considered an
extremely combustible liquid. Even though it takes a bit to heat up the oil to
get it to start to burn, once it starts burning, there is sufficient energy to
continue to process.