Bucks fire and rescue service issued a warning to never put water on to a fire involving cooking oil after an incident in Aylesbury on Wednesday evening.
Two crews from Aylesbury were called to a house in Merton Close, Berryfields at 8.15pm, after a fire in a chip pan was tackled with water.
Although the fire was out when firefighters arrived, the occupants - a man and a woman - were suffering from minor burns and smoke inhalation.
Firefighters gave them first aid and oxygen.
Group Commander Richard Priest from Bucks Fire and Rescue said: “Our advice in a situation like this is to switch off the cooker if it is safe to do so and to get out of your home, shutting doors behind you.
“Stay outside and call 999.
“Throwing water on to it will cause a plume of burning oil which can cause serious injury or even kill you.”