Three World War 2 reenactors were burned when a gas canister exploded during an airshow in Blenheim last night.
A man in his 50s was seriously injured, and a woman in her 40s and a 34-year-old man suffered minor injuries when a canister they were using with a camping stove exploded.
St John spokesman Ian Henderson said they were all taken to Wairau Hospital.
The man in his 50s was then transferred to Lower Hutt Hospital, which specialises in burn treatment.
The incident happened at the Omaka Classic Fighters Airshow on Aerodrome Rd, about 6.50pm.
Show spokesman Alex Robins said it was believed the group was cooking some food before the explosion.
He said they were not breaking any fire ban rules by using the stove.
"Those guys were victims of a product that looks like it failed.''
The group were dressed up as soldiers and formed part of the show.
"So when you come into the show, you walk through an army camp - it's World War 2 themed - and they are part of that.''
He said they were attended to immediately by emergency workers who were at the scene.