Updated 09/30/12 – 5:30 p.m.

CHICAGO (CBS) — An extra-alarm fire completely engulfed a warehouse in the Avondale neighborhood on the Northwest Side early Sunday. And from the moment fire fighters arrived, they weren’t just battling a blaze, they were solving a puzzle, unsure where the fire was, in a jumble of five warehouse buildings.

Chicago Firefighter Michael Fox said, “The five different buildings and trying to figure out how they were connected and how the fire was spreading gave us difficulty.”

CBS 2’s Derrick Blakley reports more than 200 firefighters and 82 various pieces of fire equipment responded to the 5-11 alarm blaze at an industrial building in the 2600 block of West Nelson Avenue.

“What makes it difficult is we have small water mains around here,” Chicago Fire Commissioner Jose Santiago said. As a result, crews have had to tap hydrants at another location to bring water to the scene of the fire.

The fire started around 1:40 a.m., and Santiago said around 7 a.m. that there was worry the structure could collapse because of how long it had been burning.

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Santiago said there were some structural cracks in the building, and an old water tower on the roof that was in danger of coming down.

“We’re watching the building carefully,” he said. “We’re looking at the structure itself. It’s a very unusual building. One side of it is four stories, the next side is three stories, two stories, and it’s massive, so we’re watching the building and making sure the integrity of the building is kept.”

CBS 2’s Courtney Gousman reports, around 7:30 a.m., part of a southern wall of the building collapsed, leaving a gaping hole in the southern side of the building. Part of the north side of the building also collapsed a few hours earlier.

A Level 1 Hazardous Materials alarm was also raised, due to chemicals that might be inside the structure, which might seep into the water running off from the site. However, Santiago said tests of the runoff water Sunday morning have so far turned up clean.

Although the 5-11 alarm was struck out around 9:30 a.m., firefighters remained on scene to fully extinguish the blaze, and were likely to be at the site all day to pour water on hot spots at the site to prevent the fire from reigniting to another full blaze.

While no injuries were reported during the blaze the five buildings and everything in them were completely destroyed, including Craig Sellers’ custom woodworking shop.

“I’m a little in shock right now, trying to figure out how I’m going to start over”, Sellers said.

As well as all of the instruments and electronic gear for Gary Olsen’s heavy metal band.

“It happened, what are you going to do? Nothing you can do, just watch it go down,” Olsen said.

The wall collapsed on the biggest building, a former four-story factory. And that essentially trapped the fire inside, beneath mounds of debris.

Multiple snorkel crews spent hours pouring water into the smoldering ruins, trying to drown a fire they couldn’t even see.

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