[2] Union Petroleum Company was bought out by Sinclair Oil Corporation,[3] which purchased the original lease and an additional 242 acres of land adjacent to Trainer, Pennsylvania.

[4] On March 17, 1925, Sinclair Oil opened its new $7 million state-of-the-art facility with a projected gasoline production of 6,000 gallons per day (approximately 22,712 liters).

According to the 1955 Sinclair Oil Annual Report, these expansions gave the plant an estimated crude processing capacity of 120,000 BPD (Barrels per Day).

In 2012, Phillips 66 sold the refinery to Monroe Energy, LLC, a wholly owned subsidiary of Delta Air Lines.

[15] The "mastermind" of the transaction was Jon Ruggles, and it served as part of the airlines' strategic effort to manage its fuel price risk.

Under the leadership of Delta CEO Richard Anderson, the Trainer Refinery committed to procuring more oil from domestic companies.