FINDLAY, Ohio (AP) -- The head of what's now the nation's fifth-largest oil refiner said Thursday that the new Marathon Petroleum Corp. is poised for growth over the next four years.Houston-based Marathon Oil Corp. completed the spin-off of its refining division, effectively splitting into two companies. Marathon Oil will explore and produce oil.The spun-off Marathon Petroleum division will be based in Findlay, Ohio, where it already has about 1,600 employees. It plans to add 100 more jobs at the Ohio office within the next few months. The company has six refineries in the Midwest and Southeast.Marathon Petroleum also is in the middle of a $2.2 billion expansion of its refinery in Detroit, which will allow it to process more Canadian crude oil."We have these big new investments that will soon be complete that will be providing income and cash generation for our company," said Gary Heminger, a longtime Marathon executive who becomes the new company's president.He said he also sees potential to expand the company's Speedway gas stations around the country.Ohio is giving the company $78 million in tax credits to help keep the headquarters in Findlay for at least the next 18 years. The company has pledged to put $20 million into his headquarters.Heminger wouldn't say if the company came close to leaving Ohio."We see our presence here is part of our heritage," he said.Another factor in staying was a decision by business leaders and municipal officials to speed up work on plans to protect the city from the type of flooding that swamped Findlay's downtown and Marathon's headquarters in 2007.The water knocked out the company's computer system and power for nearly a week."It had to be done to make our decision to stay here," he said about efforts to move forward on a plan to build a flood walls and levees.Funding for the project still needs to be secured.