The Transportation Safety Board is investigating after a CP freight train derailed west of Banff, Alta. Friday, sending seven cars into a creek.

No one was injured in the derailment, which took place near 40 Mile Creek, TSB spokesperson John Cottreau said.

Cottreau said a number of the cars have landed in the creek, which flows into the Bow River about 200 metres downstream in Banff National Park. A total of 15 cars were derailed.

"Seven of them are in the water," he said. "The bridge is destroyed."

Cottreau said six of the derailed cars were carrying a cement component called "fly ash," and nine of the derailed cars were carrying lentils. Neither the fly ash nor the grain are classified as dangerous under the Dangerous Goods Act.

Crews have put hay bales in the stream to try to contain the spills.

The TSB is now working with Parks Canada to address any environmental concerns stemming from the derailment.

Alberta Environment and Sustainable Resource Development said its staff are also at the scene.

Katrina Bluetchen, a spokeswoman with the department, said staff were concerned that some of the fly ash could enter the creek.

"It could affect the pH of the creek," Bluetchen explained, noting that the concrete material could also build up as sediment.

"We're still getting updates so it's a little difficult to say what the impact is."

Crews are at the site collecting information for the investigation into the cause of the derailment.

With files from The Canadian Press