Enbridge Gas Distribution has been fined $700,000 in connection with an Etobicoke explosion that killed seven people in 2003.
The natural gas explosion levelled a strip mall on Bloor Street West near Kipling Avenue in April of that year, destroying three businesses and several homes.
It happened when a construction company doing road work struck a gas line that was not properly identified and marked.
Gas escaped into the basement of the building and was ignited, the province said in a news release Friday.
Enbridge, based in North York, was fined $350,000 for violating the Occupational Health and Safety Act and another $350,000 for violating the Technical Standards and Safety Act.
Precision Utility, a Mississauga company which was responsible for marking the location of gas lines, was fined $200,000.
The excavator, Warren Bitulithic Ltd., had already been fined $225,000 in October, 2006.
"We have to make sure that companies who are engaged in this kind of business continue to be aware of their responsibilities and duties to public protection," said David McCaskill, Crown counsel for the Ontario Ministry of Labour.
In addition to the fines, Justice Robert Bigelow imposed a 25 per cent victim surcharge that goes to a provincial government fund to assist victims of crime.
Enbridge issued a statement Friday: "Enbridge Gas Distribution has continued and expanded its damage prevention efforts both within its own operations and through public and excavator awareness campaigns."
Townhouses have been built where the strip mall once stood. The only business affected by the blast that is still operating is Milano's Pizza, which moved across the street afterward.
People inside told CBC reporter Zelekha Nathoo that they wouldn't speak about the explosion because they didn't want to relive the pain.