Crews continued sifting through rubble Monday as their dangerous days-long search for a missing worker believed to be dead continued following a fatal explosion at a plant in north suburban Waukegan.
Authorities said the "entire building has collapsed into the area" rescuers had been searching, but their efforts still resumed Monday morning.
"We start on the edge and pull pieces away and go in," Waukegan Fire Marshal Steven Lenzi said of the rescue strategy.
The search is expected to continue even if rain moves into the area, according to Lenzi.
"This is by no means over until we've located all victims," Lenzi said.
At least three people are confirmed dead in the Friday blast so far. An investigation into what happened remained ongoing and an exact cause had not been determined as of Monday morning.
Police said the body of one of two missing workers was located in the wreckage of the AB Specialty Silicones plant Sunday, marking the third confirmed death in the explosion that took place Friday night.
One body had already been recovered from the building and another person, identified as 29-year-old Allen Stevens, passed away Saturday at Loyola University Medical Center, according to authorities.
"We can't go in there and do what we want to do quickly because the building is not structurally sound," said Lake County Coroner Dr. Howard Cooper. "We can't risk anyone else getting hurt or killed."
A total of four workers were taken to area hospitals, including Stevens, following the blast.
A charred metal frame and piles of debris are all that remain after the deadly explosion Friday night.
Those who died are being hailed as heroes. Investigators said they noticed a problem and were helping their coworkers exit the building when it burst into flames.
The explosion was so intense it even damaged a neighboring plant.
Officials say that when firefighters arrived at the scene, they noted heavy damage and a massive fire. Rescue workers also encountered injured workers from the plant and transported them to local hospitals. Other neighboring fire departments were called in to help battle the massive fire.
An investigator from the Illinois State Fire Marshal’s office has been at the scene to evaluate the cause of the explosion, but has not released any findings at this time.
The Illinois Environmental Protection Agency has also announced that after extensive air quality and water monitoring tests that there is no danger posed to the public by the aftermath of the explosion. OSHA investigators have also been called to evaluate the incident.
“We are shocked and heartbroken by the tragedy that occurred in our plant last night,” AB Speciality Silicones GM Mac Penman said in a statement. “We have spent the day trying our best to support all of the members of our AB family as we attempt to process this terrible loss together.
“We want to express our extreme gratitude to all the first responders who arrived at the scene. We continue to work closely with the Waukegan Fire Department and the Illinois Fire Marshal as they secure the scene and complete their investigation,” he added.