CHICAGO (CBS) – A propane tank fire spread to two garages in the Southwest Side’s Gage Park neighborhood early Friday, prompting a hazardous materials response.

Shortly after 4 a.m., fire crews responded to the report of a fire at 5026 S. Spaulding Ave., Fire Media Affairs spokesman Quention Curtis said.

Upon arrival firefighters found a garage fire that began inside a 100-square-inch propane tank, Curtis said. A Level 1 HazMat response was called due to the fact the flames were being fueled by the propane tank.

The flames spread to another garage before fire crews extinguished the blaze about 6 a.m., according to Curits. The Level I HazMat was secured at the same time.

Firefighters kept a steady stream of water on the propane tank to keep it cool and prevent it from exploding, Curtis said.

The cause of the fire remained under investigation Friday morning, according to Curtis.

As of 6:30 a.m., firefighters remained on the scene. CBS 2’s Don Schwenneker advises motorists to avoid the area.

The Sun-Times Media Wire contributed to this report.