context: Highly concentrated sources of oxygen promote rapid combustion. Fire and explosion hazards exist when concentrated oxidants and fuels are brought into close proximity; an ignition event, such as heat or a spark, is needed to trigger combustion. Oxygen is the oxidant, not the fuel, but nevertheless the source of most of the chemical energy released in combustion. Combustion hazards also apply to compounds of oxygen with a high oxidative potential, such as peroxides, chlorates, nitrates, perchlorates, and dichromates because they can donate oxygen to a fire.
question: What is needed to make combustion happen?
answers: heat or a spark oxygen an ignition event an ignition event, such as heat or a spark an ignition event
content_span_normalized_text: fire and explosion hazards exist when concentrated oxidants and fuels are brought into close proximity; an ignition event, such as heat or a spark, is needed to trigger combustion.
question_normalized_text: what is needed to make combustion happen?
context_asr: HIGHLY CONCENTRATED SOURCES OF OXYGEN PROMOTE RAPID COMBUSTION FIRE AND EXPLOSION HARDS EXIST WHEN CONCENTRATED OCIDENTS AND FULLS ARE BROUGHT INTO CLOSE PROXIMITY AN EGISTION EVENT SUCH AS A HEAT OR AS PART IS NEEDED TO TRIGGER COMBUSTION OXYGEN IS THE OCCIDENT NOT THE FULL BUT NEVERTHELESS THE SOURCE OF MOST OF THE CHEMICAL ENERGY RELEASED IN COMBUSTION COMBUSTION HASARDS ALSO APPLIED TO COMPOUNDS OF OGEN WITH HI OXIDATIVE POTENTIAL SUCH AS PEROXIDES CLORIDES NITRATES PERCLORADES AND DROM WATS BECAUSE THEY CAN DONATE OGEN TO THE FIRE 
question_asr: WHAT IS NEEDED TO MAKE COMBUSTION HAPPEN 