A412, A620T: contain a siliconized sodium bicarbonate based dry chemical. This chemical smothers fires in flammable liquids and pressurized gases and will not conduct electricity back to the operator.
Purple K Model B479: PURPLE K extinguishers contain specially fluidized and siliconized potassium bicarbonate dry chemical, effective on Class B flammable liquids and pressurized gases. It is electrically non-conductive.
Purple K has been the choice of oil, gas, chemical and utilities industries as the preferred agent.