Boy’s oily trousers started fire in his bed

A boy’s pants spontaneously combusted and started a blaze in his bed, prompting a warning from firefighters to be careful with oils.

There have been 62 avoidable fires in Waikato caused by spontaneous combustion over the past five years.

In one case, a child was helping his dad paint with linseed oil, and rubbed oily hands on the legs of his cotton trackpants, Fire and Emergency risk reduction inspector and adviser Ed Hopping told Stuff.

The boy was told to clean his room before going out, and shoved the pants under the pillow on his bed. The sun came out and the linseed oil oxidised in the heat and smouldered away for some time before the smoke alarm alerted the family.

The bedding was put out the window, but the sudden injection of oxygen caused it to burst into flames. The local fire brigade extinguished it outside, and made sure the mattress was fully extinguished.

‘‘They were very, very lucky,’’ Hopping said. ‘‘It’s more common than people think.’’

A garage in Claudelands, Hamilton, also caught fire after oily towels were washed and put in the drier.

The cold wash did not completely get rid of the oil, and the rags ignited in the heat from the drier.

The house was two storeys, with the garage underneath, and the blaze spread to the main house. For spontaneous combustion to occur, there has to be enough heat to cause a spark. It mostly occurs with oil-soaked rags.

It is commonly due to organic oils, including drying, cooking, and massage oils.

As the oil is exposed to oxygen, the rags act as an insulator and the oil becomes hot enough to cause the fabric to smoke and eventually ignite. To avoid a fire, rags should be stored in a noncombustible metal container with a tight lid, away from the house and combustible materials.

It’s best to lie rags used with linseed oil flat on a concrete driveway to dry off completely.

If washing, a hot wash and strong detergent is needed to get the oil out.