The United States experienced a dramatic increase in train-related oil spills last year.

Data compiled by the federal Pipeline and Hazardous Materials Safety Administration shows 1.15 million gallons of crude oil spilled from rail cars in 2013. That’s more than was dumped during the previous 37 years combined (800,000 gallons).

“The spike underscores new concerns about the safety of such shipments as rail has become the preferred mode for oil producers amid a North American energy boom,” wrote Curtis Tate of McClatchy.

Oil production has been particularly strong in North Dakota, which has greatly expanded its output since the discovery of a new oil field in 2006. The state’s oil was involved in three major train spills during 2013.

A train originating in North Dakota dumped nearly 750,000 gallons of crude oil near Aliceville, Alabama, in November.

North Dakota oil was onboard the train that derailed and exploded in the Canadian town of Lac-Megantic, Québec, on July 6, killing 47 people.

The Pipeline and Hazardous Materials Safety Administration oil spill data for last year does not include incidents in Canada.

The agency’s total for 2013 also does not factor the oil spilled on December 30 near Casselton, North Dakota. Another federal agency, the National Transportation Safety Board, estimates more than 400,000 gallons of crude oil were spilled there.

It was only a few years ago that crude oil started being carried in 80- to 100-car trains. Between 1975 and 2009, no oil spills occurred during eight of those years, and spills of just one gallon or less were reported in five other years.

-Noel Brinkerhoff

To Learn More:

More Oil Spilled from Trains in 2013 than in Previous 4 Decades, Federal Data Show (by Curtis Tate, McClatchy)

Brown Budget Anticipates Surge in Inland Oil Spills from Out-of-State Rail Transports (by Ken Broder, AllGov California)