An overheated laptop computer left in a bed was the cause of a duplex fire in Montague early Wednesday morning, says the provincial fire marshal.

A mother and two children escaped from the building on Parkman Avenue without injury after a fire broke out around 5:45 a.m, said David Rossiter.

A boy was sleeping in an upstairs bedroom when he smelled smoke coming from the laptop on his bed.

A working smoke detector went off.

Rossiter said a cooling pad was used.

"It did have a small cooling pad underneath it, however, because the laptop was in the bed and had clothing around it and whatnot, it wasn't able to dissipate the heat that the laptop generates," said Rossiter.

"Even when they are closed, in sleeping mode they still will generate a certain amount of heat and that is basically where that fire originated from. They should be placed on a hard surface and not on a fabric surface or bedding or bed or anything like that."

This was the second fire on P.E.I. in the last six weeks caused by a laptop.

Although the fire was mostly contained to a bedroom, there is smoke damage in the rest of the unit.

The other side of duplex was unaffected by the fire.

The family of three is temporarily staying with relatives and receiving help from the P.E.I. Red Cross.