The Canadian Coast Guard is working to determine how much diesel fuel has spilled into the Fraser River after a tugboat pulling a barge of gravel capsized overnight.

The 19-metre-long George H. Ledcor capsized in the river between Vancouver and Richmond, B.C., at around 10 p.m. on Monday.

Kiri Westnedge, a spokesperson for the Canadian Coast Guard, said that all four crew members from the boat were rescued by another tugboat nearby.

Westnedge said the boat has a capacity of 22,000 litres of diesel fuel but it’s not yet clear how much fuel was actually onboard.

On Monday, crews from Western Canada Marine Response Corporation were throwing absorbent pads into the river to soak up the fuel, which was sending a strong odour into the air.

Ledcor, the construction firm that owns the tugboat, said it is planning to salvage the tug. A boat with a crane on top could be seen in the river on Tuesday afternoon.

A Vancouver Park Board biologist was at the scene on Tuesday warning dog owners to keep their pets out of the water.

With a report from CTV Vancouver’s Nafeesa Karim