The Surrey Fire Department is investigating a diesel and gasoline spill into the Nicomekl River.
Battalion Chief Dave Rivett says the fuel originated from a nearby industrial area.
Rivett says it's hard to know how much of the fuel went into the river near the Surrey and Langley border.
Firefighters have boomed off the river at several crossings to stop the spill from spreading.
Rivett says the Environment Ministry will take over the investigation.
The Nicomekl River runs from the headwaters in Langley and travels west through the city to Crescent Beach in Surrey.
