Four fire engines and around 25 firefighters were called to a fire at a house on Jenningtree Road in Erith.
Half of the first floor and part of the ground floor were destroyed by fire. Four people evacuated the property before the Brigade arrived. A mother and her teenage son were treated on scene for smoke inhalation by London Ambulance Service. Two cats were rescued by crews wearing breathing apparatus, sadly one of the cats died at the scene.
The fire is being treated as accidental and is believed to have been caused by the catastrophic failure of lithium batteries.
A London Fire Brigade spokesperson said: "Lithium batteries store a significant amount of energy in a very small space and are much more powerful compared to other types of batteries. If that energy is released in an uncontrolled way, then a fire or explosion may result. If there is overheating, crushing, penetrating or overcharging, then a fault can occur within damaged battery cells which may cause the battery to catch fire
"Fires involving lithium batteries, which power devices, can be ferocious, producing jets of flame. The blaze is also hot enough to melt through metal. This type of fire produces a highly flammable, explosive and toxic vapour cloud which should never be inhaled. The fire can also be extremely challenging to put out. Our advice is to get away to safety and call 999.
"Lithium batteries, or the devices powered by these batteries, should be stored and charged in a location away from where people live, such as in a shed or a garage. If they have to be stored inside, make sure there is smoke detection fitted, it’s kept it in a room where you can shut a door and contain a fire and your means of escape is not obstructed. Never store or charge on an escape route such as a hallway or by an exit to a property.
"It is also important to ensure that you buy your batteries from a reputable seller and to ensure you are using the correct charger for the batteries."
The Brigade's 999 Control Officers received a call to this incident at 1614 and mobilised crews from Erith, Bexley, East Greenwich and Sidcup fire stations. The incident was over by 1755.