A Kitchener on Wednesday morning, killing one woman and critically injuring a man.
He was airlifted to hospital in Hamilton.
Neighbours the blast from kilometres away.
Residents of 16 homes were evacuated, and Red Cross was called to assist those displaced.
Officials estimated it could be at least two and up to three days before some residents could return.
The north side of the street was to be without gas for at least 48 hours.
While the investigation is ongoing, early damage estimates are in the millions of dollars.
Additional support services have been made available to those affected in the area.
One dog out of three that lived in the residence was confirmed escaped.