>the earliest refrigeration equipment from the 01860s used "chimogene", which we now know as propane and butane, which is not toxic but disastrously inflammable

>the earliest refrigeration equipment from the 01860s used "chimogene", which we now know as propane and butane, which is not toxic but disastrously inflammable Hydrocarbon refrigerants went out of vogue for performance reasons but were/are still used the world over in certain applications and there's been a recent uptick now that we care more about not destroying the environment. The fuel:air mix you need for fire is narrow enough that ignition is mostly not a problem in practice, it also helps that society have moved away from open flames for a lot of heating and lighting applications. Google "R600a"