DSEAR regulations apply to prescribed hazardous chemicals listed in the CHIPS regulations. DSEAR - Dangerous substances and explosive atmospheres Regs are all about the identification and mitigation of risk where a volatile flammable liquid or gas may result in an explosive atmospheres. Take a look at the excellent guidance available on
www.hse.gov.uk.. In addition to the guidance on DSEAR theres an excellent document aimed at general safety in vehicle repair workshops.
Petrol, LPG, acetone, are examples of such hazardous substances. Lubricating oils are pretty inert things that have a very high flash point and at normal temperatures give off no flammable vapours- indeed you would struggle to set it on fire without help of a very large- and deliberate - ignition source.