British Columbia Environment Minister Barry Penner says CN Rail may face charges related to a 2005 derailment in the Cheakamus Canyon.

Officials from Environment Canada and B.C. Conservation officers searched CN offices in Edmonton, Surrey and Prince George on Thursday.

"CN co-operated fully with the investigators as they conducted their search," said CN spokesperson Jim Feeny.

Nine CN freight cars jumped the tracks north of Squamish in August 2005, spilling caustic soda in the Cheakamus River. More than 500,000 adult and young salmon, steelhead, trout, lamprey and other species were killed after the derailment.

Penner says although there's been no decision on charges yet, CN may face penalties under both federal and provincial legislation.

"Obviously there's the federal Fisheries Act which could come into play," said Penner.

"But we also have in B.C. the Environmental Management Act and under that piece of provincial legislation, it does hold the prospect of fines up to $1 million."

The Transportation Safety Board is investigating the technical reasons behind the Cheakamus Canyon wreck and could produce a report by the end of May.

In February 2006, CN Rail agreed to contribute $1.25 million over five years to restore the Cheakamus River system in a partnership with the Pacific Salmon Foundation.

Penner said earlier he wants protective guards to be put along the canyon sections of the river to prevent future rail accidents.

Cheakamus Canyon is about 45 kilometres north of Vancouver.

With files from the Canadian Press