Welder burned in explosion

A welding explosion has left a man in his 20s with burns covering almost all of his body.

The critically injured man was transferred from Wellington to Middlemore Hospital in Auckland last night with burns to 80 per cent of his body.

It is understood the man was welding in the garage of his Upper Hutt home when a barrel containing an unknown substance exploded.

An 18-year-old woman and a baby in the garage at the time escaped with minor burns.

After the explosion the man immediately ran into the shower.

Aaron Hartle, acting team manager from Wellington Free Ambulance, said getting into the shower quickly was the best thing the man could have done.

"It's remarkable ... considering the seriousness of his burns, to still keep a clear head."

The fire service and police are investigating the cause of the explosion.