LANSING, Mich. -- Federal regulators will allow Enbridge Inc. to gradually restart a repaired pipeline that spilled hundreds of thousands of gallons of oil into a southern Michigan waterway this summer.

The Pipeline and Hazardous Materials Safety Administration said Wednesday that the gradual restart will be "tightly controlled and closely monitored." It wasn't immediately clear when service on the pipeline might be restored.

Regulators say the monitoring will include an independent third party that reports to the pipeline safety agency.

The pipeline runs from Griffith, Ind. to Sarnia, Ontario. A leak found in late July spilled between 820,000 gallons to 1 million gallons of oil.