Flammable liquid

The Occupational Safety and Health Administration (OSHA) of the United States Department of Labor defines a liquid as flammable if it has a flash point at or below 93 °C/199.4 °F.

[1] Prior to bringing regulations in line with the United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) in 2012, OSHA considered flammable liquids to be those with a flash point below 37.8 °C/100 °F.

[2][3] Studies show that the actual measure of a liquid's flammability, its flash point, is dependent on the local air pressure, meaning that at higher altitudes where the air pressure is lower, the flash point is also lower.

[4] Both OSHA and GHS further divide flammable liquids into 4 categories: These categorizations are dependent upon a set altitude and atmospheric pressure, as both boiling point and flash point change with changes in pressure.

[4] Both GHS and OSHA require the labeling of flammable liquids, on containers and safety data sheets, as follows:[3][5]