(CNN) Three men believed to have been trapped in a massive explosion at an Illinois industrial plant warned others to leave the building before the blast, officials believe.

Three people have so far been confirmed dead after the explosion Friday night at AB Specialty Silicones in Waukegan, about 40 miles north of Chicago.

One person died of their injuries in a hospital, two bodies have been recovered from the scene of the blast and one person is still missing, authorities say.

Waukegan Fire Marshal Steven Lenzi told reporters Sunday that some of the nine workers in the building when the explosion occurred alerted their colleagues beforehand.

"From the information we have, some of the plant personnel -- especially those that are still missing -- alerted others to the issues going on shortly before the incident. At this point we have determined they did help people get out of the building," Lenzi said.

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