The owner of the St. Paul Park oil refinery said Monday that repairs from a Sunday fire likely will cost $10 million, take three to four weeks to complete and reduce output for the quarter.

Northern Tier Energy said the fire in the refinery’s larger crude distillation unit was put out within three hours by company firefighters and units from St. Paul Park and Newport. No one was injured in the accident, which also shut down other refinery operations.

The Ridgefield, Conn.-based company said a smaller distillation unit and other components are being restarted, allowing the refinery to operate at lower capacity while the large unit is repaired.

Maintenance also will begin immediately on an undamaged fluid catalytic cracking unit that had been scheduled for an October shutdown, Northern Tier said in a statement.

The fire’s cause and the extent of the damage were being assessed, the company said.

The refinery should be operating at approximately 40,000 barrels per day by early October, and ramp up to 85,000 barrels per day by mid-October, but throughput for the quarter will be down, the company said.

Northern Tier Energy also operates 163 SuperAmerica convenience stores and supports 73 franchised Super­America stores, primarily in Minnesota and Wisconsin.

DAVID SHAFFER