Updated

Federal regulators have proposed a $3.7 million civil penalty against the Canadian owner of a pipeline that ruptured in 2010, dumping more than 800,000 gallons of oil into a southwestern Michigan river.

The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration said Monday it's also proposing 24 enforcement actions against Calgary, Alberta-based Enbridge Inc. It would be the largest civil penalty that agency has imposed.

The agency said investigators found numerous violations of its hazardous liquid pipeline safety regulations, including failure to follow procedures and operator qualification requirements. The company has 30 days to respond.

A 30-inch pipeline ruptured July 25, 2010 in Calhoun County, about 60 miles east of Grand Rapids.

The pipeline extends from Griffith, Ind., to Sarnia, Ontario.