Waching daily Aug 31 2018

, authorities said.Firefighters pulled one person out shortly after the collapse at the one-story brick building on Chicago's far South Side

It took about two hours to rescue the second person, who was 'buried and entombed' by fallen debris, Chicago Fire Commissioner Jose Santiago said

 The other people who were injured were taken to hospitals in serious-to-critical condition, Fire Department spokesman Larry Merritt said

Authorities said they are investigating whether the explosion was caused by a buildup of methane, a byproduct of the water treatment process

  Paramedics attended to the man who was trapped inside for two hours while specially trained firefighters tunneled beneath the rubble to reach him and remove a metal beam from his legs

 The man, who remained conscious, suffered a broken jaw and leg and was airlifted to the University of Chicago Medical Center, where he was in critical condition

The explosion occurred shortly before 11.00am Central at the Calumet Water Reclamation Plant's sludge concentration building, according to a statement from the Metropolitan Water Reclamation District, which operates the plant

One employee who was involved in the accident described some of what happened to his wife, Gina Ruiz, who said she received a phone message from her husband

  Share this article Share Her husband had been working inside the plant, told her there had been an explosion and that his co-workers were trapped inside

She said he told her the explosion 'blew the roof off and (it) came back down' and that 'there were a lot of guys trapped inside

'Her husband was hit by falling pieces of the roof but not seriously injured, she said