Firefighters continue to fight a massive blaze that started Thursday morning, engulfing a 250,000-square-foot document storage warehouse in Bartlett. 

Firefighters were called to the Brewster Creek Business Park around 11:00 a.m. and when they arrived the fire was not widespread. 

Crews initially conducted interior operations. Officials said a sprinkler system initially kept the fire in check, but when a series of steel racks being used to store boxes collapsed, there was no saving the warehouse, according to ABC 7 Chicago. 

Firefighters were forced to retreat to a defensive position the sprinkler system was taken out.

As of early Friday morning, firefighters continue to operate at the scene controlling the hot spots.