Over 50,000 Chicago area telephone users were affected, including businesses, hospitals, and Chicago's O'Hare and Midway airports, after the fire damaged the main switching room in one of the largest switching systems in the state. It took Illinois Bell over two weeks of round-the-clock effort to fully restore telephone service for the region, replacing over 118,000 circuits, cables, and other materials lost in the fire.
Joe Reynolds, president of RTI, was the lead investigator appointed by the state of Illinois in the days following the fire. He and his team were able to determine the cause of the fire was one electrical power cable, whose insulation was damaged when trays of other cables were being removed with crowbars, came into contact with an armored cable. An automated fire alarm was triggered at 3:50 p.m, but was believed by Illinois Bell to be a power blip caused by passing thunderstorms. It wasn’t until 4:20 p.m., when a second alarm was triggered, that a technician was dispatched and discovered the fire. By that point telephone service had been knocked out, and unable to call the local fire department, the technician flagged down a passing car to report the emergency. Hinsdale firefighters arrived at 5:02 pm, and spent nearly two hours attempting to shut down the power from the building’s generators as a local power company, Commonwealth Edison, could not be contacted. While the fire raged, the burning cable insulation released toxic fumes, hospitalizing 10 firefighters as a result. The fire was contained after six and a half hours, but not before damaging hundreds of millions of dollars of communications equipment.
``All fires are preventable," said Joseph Reynolds, in an article written by the Chicago Tribune. ``But I don`t think we could have anticipated this. Hinsdale is similar to thousands of other buildings across the country. Even if the fire had been extinguished in 10 minutes, the phone damage, which was caused mostly by smoke, would not have been stopped.``