The refinery has been in continuous operation since 1952[1] and supplies petroleum products to the southern Ontario region including Toronto and its suburbs via the Sun-Canadian Pipeline.

[3][4] In 1952, Sun Oil Company (later known as Sunoco, and eventually Suncor Energy), commissioned the Sarnia refinery.

The location of the refinery in Sarnia was strategic due to its proximity to both the Alberta oil supply from the creation of the Interprovincial Pipe Line Company (now Enbridge) and major transportation routes along the Great Lakes.

[7] In 2009, the merger between PetroCanada and Suncor meant that Sarnia would become part of a much larger refining system with plants in Edmonton and Montreal.

A major period of investment was undertaken from 2004-2007 at the site with modernization activities and the construction of several new units.

Tom Ryley, SVP of Refining said that “Suncor made a substantial investment to strengthen the integration between our oil sands operation in Northern Alberta and our Ontario-based businesses.” At peak, the construction project employed 1,600 workers.