A 50-gallon toxic spill from a tanker truck has closed the northbound lanes of Interstate 5 through Seattle.

The Seattle Fire Department says sodium borohydride leaked from a tanker truck near the interchange with Interstate 90. All northbound lanes of I-5 were closed just before 2 p.m.

A hazardous waste removal team is on the scene and crews are telling people to stay at least 300 feet away from the spill. The spill is spread over about 1,500 yards.

Fire officials say the substance is used to bleach wood and is toxic.