Six people were injured and nine houses damaged when the sudden blast ripped through in Northwood's Marble Court on July 19 last year.
The blast waves from the explosion threw chunks of roof tiles and other debris around the neighbourhood.
Neighbours and passers-by who pulled stunned survivors from the burning debris told the Herald at the time they were amazed that nobody was instantly killed.
One year on, WorkSafe pressed charges against Gas Unlimited owner Gregory Smith.
He appeared in the Christchurch District Court this morning keeping his eyes downcast.
Judge David Saunders told the Court this appears to be a case of carelessness rather than wilful damage.
He said Smith is most likely looking at financial consequences.
Smith will reappear for sentencing on December 15.
The blast waves from the explosion threw chunks of roof tiles and other debris around the neighbourhood.
Neighbours and passers-by who pulled stunned survivors from the burning debris told the Herald at the time they were amazed that nobody was instantly killed.