An explosion on an Enbridge oil pipeline in November 2007 in Clearbrook, Minn., killed two workers. An explosion on an Enbridge oil pipeline in November 2007 in Clearbrook, Minn., killed two workers. (Eric Hylden/Associated Press/Grand Forks Herald)

Enbridge, whose pipeline is responsible for a massive oil spill last month in a Michigan river, has been fined $2.4 million US over a 2007 case in Minnesota.

The U.S. Department of Transportation announced the penalty Tuesday against the Calgary-based company for pipeline safety violations.

Two Enbridge workers were killed in 2007 when leaking oil from a company pipeline in Clearbrook, Minn., ignited.

A Pipeline and Hazardous Materials Safety Administration investigation found Enbridge failed to safely perform repairs.

The Michigan accident involves 3.1 million litres of oil that spilled into a tributary of the Kalamazoo River near Marshall on July 26.

The pipeline runs from Griffith, Ind., to Sarnia, Ont.