The search continues Tuesday for a fourth missing worker, who is presumed dead, inside the unstable facility. Lake County Coroner Howard Cooper said they have gone through the whole building and taken everything out, and while they have an idea of where the fourth victim may have been, they are still searching for their remains.
The Lake County Coroner's Office said the process of bringing closure to the fourth victim's family is extremely difficult. Cooper's team is slowly and methodically sifting through debris, going back through parts they've already searched bit by bit.
"We don't know what condition the body is going to be in, we don't know if we are looking for a full body or a fragmented body, so we have to keep our eyes open and look for everything," Cooper said.
"The only updates that we gave the family are that we have additional resources that have been arriving all day. Federal resources," said Waukegan Fire Chief George Bridges, Jr.
Nine people were inside the plant at the time of the explosion, which could be felt miles away and scattered debris for blocks.
Allen Stevens, 29, of Paddock Lake, Wisconsin, was rescued from the rubble and airlifted to Loyola Medicine's Burn Center. He died at the hospital on Saturday, from burns suffered in the explosion.
"Great guy. Worked here a couple of years. Always had a smile on his face, ton of friends, hard-working. We knew he was going to go places," Craig Schilz, Stevens' former co-worker.
Search teams recovered two bodies from the scene over the weekend.
Relatives confirmed 57-year-old Jeff Cummings of Kenosha, Wisconsin, was killed in the blast.
His son said he was a supervisor who ran back in to the plant to make sure his guys were out. His family calls him a hero.
Byron H. Biehn, 53, of Brighton Township, Wisconsin, was also killed in the explosion. His family called the loss unimaginable.
Cooper confirmed the identities at a Tuesday afternoon press conference. He said autopsies were performed on both Cummings and Biehn, but preliminary results are pending toxicology.
"We have been in close contact with both families and our deepest condolences go out to them during this difficult time. This is truly an awful tragedy of epic proportion. We continue to work on scene, in efforts to recover the final victim. Our condolences also go out to the entire AB Specialty Silicones family. We know this has been a trying time for you all, as well," he added.
WATCH: Chopper 7HD over large explosion at AB Specialty Silicones plant
Tuesday is the fourth day emergency crews sifted slowly and carefully through the rubble for the last remaining victim.
"Every time you cut a piece away, every time you pull a piece away, you have the possibility of further collapse," Waukegan Fire Marshal Steven Lenzi said.
The next big task for crews is to piece together evidence buried at the scene and figuring out what caused the explosion.
"We don't want to destroy any evidence that may be under there, and we need to do it slowly and methodically, safely, for all personnel involved," Lenzi said.
The Lake County Coroner's Office, Waukegan Police Department, Waukegan Fire Department and Office of the State Fire Marshal are working together on the investigation, which could take weeks to complete.