A train carrying crude oil derailed early Saturday and exploded in northern Ontario, the second such accident in less than a month. While workers tried to extinguish the blaze and contain the train’s oily contents, which had already begun to spill into a river, critics once again questioned the safety of rail transport of crude oil, which is on the rise in both the United States and Canada.

The train was 30 to 40 cars long and was transporting crude from Alberta to eastern Canada, the Canadian Broadcasting Corp. reported. The incident occurred less than a month after a train carrying crude in cars of the same model ran off the tracks and exploded along a similar route.

The cars on both trains were designed to new standards said to be safer than those on which the rail industry had long relied for the transport of flammable liquids, following calls for improved safety. The new model car, known as CPC-1232, features normalized steel and extra reinforcement at the top and bottom of the containers, The Star reported.

Residents in the affected area do not seem reassured. “People here are on pins and needles,” Roxanne Veronneaum, owner of an inn in the nearby town of Gogama, told The Star. “The tracks run right through town. … I’m sure that there’s going to be a lot of talk afterward that this shouldn’t be in the middle of our town.”

Critics including those at the Transportation Safety Board of Canada have also said the standards for the new rail cars are still not high enough given the volatility of their contents. In Saturday’s incident, five of the 10 cars that derailed landed in the Mattagami River and spill oil into the waterway, The Star said. Workers were on site with boons to try to contain the spill. 

CN spokesman Mark Hallman said Chief Operating Officer Jim Vena “apologizes to the residents near Gogama for the inconvenience and disturbance caused by a second company derailment in such a short period of time,” The Star said. 

The increased extraction of oil from the tar sands of Canada, primarily in the vast plains of Alberta at the center of the country, has created a greater demand for crude shipments along Canadian National Railway routes. Such shipments have risen from just 500 carloads in 2009 to 160,000 in 2013, the Railway Association of Canada reported. South of the Canadian border, the situation is very similar -- shipments of crude oil went from 10,800 carloads in 2009 to 400,000 in 2013, the Association of American Railroads reported.