Three men accidentally blew up their vehicle then drove themselves to hospital suffering serious burns.
Police said the men were in a Toyota Hilux on Saturday, at Whakamahi Beach near the Wairoa River mouth, when fumes from a leaking gas cylinder exploded.
"They had prepared for camping and one lit a cigarette," Constable Johnny Yuile said. "It must have been leaking and it exploded and sort of blew up the truck - blew out the windows and panels."
He said the outside door panels were bent "but I don't know if the doors were damaged because they were trying to boot them open, because they were stuck".
They drove the damaged vehicle to Wairoa Hospital about 1pm and were treated for burns.
Mr Yuile said the man sitting closest to the camping stove suffered burns to his face.
"They must have assumed it was safe. It was probably unlucky they didn't smell the gas."
He said the explosion, from a gas cylinder similar to a can of fly spray, may have prevented the three local men from passing out from the fumes in the enclosed cab "so perhaps they escaped serious injury".
Wairoa Volunteer Fire Brigade chief fire officer Grant Duley said they were called to the hospital to make sure the men's ute was not a fire risk.
He said there was evidence of seat covers having burned but there was no fire danger.
"It must have been like a flash and put itself out," he said.
"By the time we got there it was all out bar the shouting."
The men were flown by the Lowe Corporation Rescue Helicopter to Hawkes Bay Regional Hospital where a representative said they were in a stable condition and likely to be transferred to Hutt Hospital.