HOUSTON, June 25 (Reuters) - Operations at Marathon Petroleum's MPC.N 631,000 barrel-per-day (bpd) Galveston Bay Refinery in Texas City, Texas were normal on Thursday following a brief fire in a power plant and a unit upset earlier in the week, said people familiar with plant operations.

Marathon spokesperson Jamal Kheiry declined on Thursday to comment on operations at the refinery, which is the second largest in the United States.