Five people were treated by the emergency services after a wheat bag caught fire at a flat in Aylesbury.
One crew was called to Prebendal Close at around 10pm on Wednesday December 30.
Firefighters used a bucket of water and gave oxygen to a woman who was suffering from the effects of breathing in smoke.
Three other women and a man were assessed by paramedics as they were also exposed to the smoke.
The wheat bag, pictured above, caught fire after being heated in a microwave oven for too long.
The smoke then set off an automatic fire alarm.
Crew commander Kieron Thomas said: “This incident illustrated not only how dangerous wheat bags can be if they are not used properly, but also how important it is to have working smoke alarms.”
Firefighters gave safety advice including:
Never leave the bag unattended when heating
Ensure the microwave turntable turns freely with the wheat bag on it and is not obstructed
Do not use the bag if there are any signs of over-use, such as discolouration or a smell of burning
Never reheat the bag until it has completely cooled, which could be up to two hours