Fire and explosion hazard classification of liquids is important for fire safety both inthe workplace and at home. Different countries have established their ownclassifications of flammable and combustible liquids that show a tendency to converge.The history of such classifications is associated with the oil and gas industry revolutionin the second half of the 19th century in the USA that had led to the emergence ofcheap kerosene on the market, which marked the beginning of the “kerosene era”when kerosene illumination replaced the illumination by candles. A side effect of thischange was the growth of fires and explosions due to imperfect constructions ofkerosene devices and the use of “unsafe” low flash point kerosene. The situation withfire and explosion hazards of kerosene caused great concern in many countries and thestudies were carried out to identify and establish criteria for “safe” kerosene andimprove the constructions of oil lamps and kerosene stoves. Flash point and burning point that characterized kerosene flammability and explosiveness were selected as suchcriteria. Kerosene safety criterion based on flash point (Ts) was expressed as a simpleequation: Ts = RT + Δ (where RT is room temperature and Δ is additional heating ofkerosene lamps tank by flame, sunlight, etc.). The US states established their own safekerosene criteria based on this equation. The first US classification of flammableliquids only appeared in 1936 because the USA was the main exporter of kerosene inthe late 19th and early 20th century and in most cases the US government wascomplying with other countries’ fire and safety requirements. Eventually, NFPA 30, IP15, OSHA and ANSI Z129.1-2006 classifications were developed. The keroseneapproach to determining Ts may be traced in all of these classifications.