(Adds comment from Transport Minister Lisa Raitt)
March 12 (Reuters) - Thirteen cars on a Canadian National Railway Co train went off the tracks in rural Manitoba on Wednesday night and spilled some petroleum product on the ground in the company's third derailment in a week.
There were no injuries and no threat to the public from the latest derailment, CN spokesman Brent Kossey said on Thursday. The train was carrying refinery cracking stock, which spilled from one car.
Canadian Transport Minister Lisa Raitt used the accident to reiterate her calls from earlier in the week that the company should be called to answer questions before a parliamentary committee.
"What's going on operationally?" Raitt told reporters following a speech. "I can hear from CN, but I think CN should talk to Parliament and should talk to Canadians."
On Saturday, a CN oil train derailed and burned in northern Ontario. Also in Ontario, a train hauling empty tank cars that had recently held hazardous liquids went off the tracks on March 5.
In February, another CN oil train derailed and ignited a fire, also along the railway's northern Ontario main line.
Kossey said the Wednesday night spill had been contained and that CN was working with Manitoba environmental officials to clean up the product from the ground adjacent to the track. No waterways have been affected.
Shares of CN were down 17 Canadian cents at C$85.56 in midday trading. (Reporting by Scott DiSavino in New York, Allison Martell in Toronto and Mike De Souza in Ottawa; Editing by Alden Bentley, W Simon and Lisa Von Ahn)