Two railroad cars that caught fire in an industrial area of Tacoma halted traffic for several hours on State Route 509 and prompted the evacuation of nearby businesses Wednesday.

The fire disrupted the southbound Sounder commuter schedule, and Sound Transit had to ferry train passengers on buses past Puyallup.

The fire started around 3:30 p.m. on River Street, near the intersections of Portland Avenue and Portland Avenue, in a tanker filled with denaturated alcohol, according to the Tacoma Fire Department.

Sixteen fire companies and hazardous materials specialists were called in to fight the blaze.

Authorities said it was contained by 5:30 p.m., and no injuries were reported.

It was believed that 30,000 gallons of alcohol were spilled and some of it soaked into the Puyallup River.

Authorties did not immediately know what caused the fire, although they said a collision could have been a possible cause.

A worker nearby reported hearing an explosion before the fire broke out.

Officials said the fumes did not pose a health hazard and that the nearby businesses were evacuated as a precautionary measure.

The highway reopened at about 3:30 Thursday morning, officials reported.

Sounder commuter rail service is running on schedule, the transit agency stated.

Update: Investigators said the massive fire that caused the closure of State Route 509 in Tacoma Wednesday and prompted evacuations was probalby caused by a spark from misaligned rail cars.

The fire spread Wednesday afternoon after a car carrying denatured alcohol burst into flames.

The highway sustained minor damage but was deemed safe for traffic and was reopened Thursday morning.