Park Ridge Deputy Fire Chief Jeff Sorensen said the blast, which originated inside a piece of relatively new dry cleaning equipment in the rear of Holt Cleaners, 29 S. Fair view, was either caused by solvents used in the machine or an equipment malfunction. An insurance company is now conducting its own investigation and is working with the business owner, the building's landlord and the machine manufacturer,Sorensen said.

The business has since been allowed to reopen, saidSteve Cutaia, of the city's building department. Sorensen said theoperator told the fire department that all of the clothing that hadbeen inside the building was sent to another location be cleaned again.

Initially concerned that the explosion might have been caused by natural gas, gas service was cut off for several hours to the dry cleaners, as well as a new pizza restaurant that had just opened next door.
A man and a woman, both operators of the dry cleaners were transported to Advocate Lutheran General Hospital following the explosion, but have since been released, Sorensen said.
A small fire resulted from the explosion, but it was extinguished with a fire extinguisher before firefighters arrived. Other than four windows that were shattered by the blast, no damage was caused to the building itself, Sorensen said.