UPDATED 01/04/10 5:44 a.m.

CHICAGO (CBS) — An open laundromat caught fire on the Far Souht Side overnight, and the pressure was so great that the roof collapsed.

Crews responded to the fire at 10940 S. Michigan Ave. about 10:30 p.m. and and found a one-story building containing the Wash Tub Laundry was fully engulfed in flames, Fire Media Affairs Chief Joe Roccasalva said.

A 2-11 alarm was raised for the fire, officials said.

The blaze was extinguished about 11:45 p.m., and crews were still putting out some hot spots at the building about midnight, he said.

No injuries were reported, and the cause of the fire remained under investigation early Tuesday, Roccasalva said.

The Sun-Times Media Wire contributed to this report.