Cleanup efforts are expected to take more than one week following a freight train derailment in western Quebec.

At least 20 rail cars came off the tracks near the small town of Saint-Polycarpe, about 70 kilometres west of Montreal, around 7 p.m. Monday.

There were nearly 100 rail cars in the Canadian Pacific freight train, some of which contained propane and diesel fuel. While those substances did not spill, vegetable oil did leak out of one car for a period of time before being contained.

Most of the derailed cars landed in farm fields. Saint-Polycarpe fire chief Michel Belanger said four of the cars ended up in a nearby river.

“There is absolutely no leaks [into the river] from any of the cars that were derailed,” he told CTV News Montreal.

Belanger said removing the train from the area would likely take at least one week.

Local authorities said they were not aware of any injuries.

The cause of the derailment has not been determined.

“There’s going to be an investigation in this particular case, as it has to be, as it should be, and we’ll wait for the conclusions of that investigation,” Quebec Public Safety Minister Martin Coiteux told CTV Montreal.

The Transportation Safety Board of Canada had an investigator at the site on Tuesday. Also on-site were CP crews.

“Any high-traffic area involving lots of trains per day is going to be an important line to the railway, so it’s vital that they get it cleaned up and operational as soon as possible,” Transportation Safety Board of Canada inspector Clayton Finch-Field told CTV Montreal from the scene.

Saint-Polycarpe Mayor Jean-Yves Poirier said Tuesday that initial cleanup efforts were going well.

“They are fixing the rails,” he said. “They are feeling comfortable with all the intervention that they have to do.”

Poirier called it fortunate that the train went off the rails in a rural area, as opposed to in the town centre, saying the outcome could have been much different had the derailment site been in a different location.

“We’re lucky that it happened here,” he said.

With a report from CTV Montreal’s Angela MacKenzie