This from Steve Redick:
This was Proviso East High School at 807 S First Ave in Maywood, IL. From what I could see from the outside they had a fire in at least 1 classroom and it sounds like it spread vertically 1 or 2 floors. Long leadouts and I believe they added additional lengths once they were operating inside. Reports from the scene prior to my arrival indicated some heavy smoke conditions. The only aspect of the operation I was able to see was the deployment of MABAS MVU10, operated by the Lyons FD. These units are similar to those operated by the CFD. This is an old building, and presented some unusual tactical problems.
An extra-alarm fire broke out at Proviso East High School in Maywood on Saturday evening, causing damage and startling families gathered for a school play. No injuries were reported.
The fire was reported at about 9 p.m. at the west suburban high school, 807 South First Ave., and was elevated to a three-alarm fire at about 9:40 p.m., officials said.
Speaking at the scene about 11 p.m., Maywood Fire Chief Craig Bronaugh said the fire caused “substantial damage” but that there were no reports of injuries. The fire started in a social office on the second level of the school, said Bronaugh Sunday morning.
The cause of fire remained under investigation, Bronaugh said.
thanks Dan