The AB Specialty Silicone plant in Waukegan, located about 80 km north of Chicago, was emptied on Saturday morning by rescue teams after a massive explosion.
The officials found the body of a deceased employee. Four other employees were taken to the hospital and two others refused treatment.
Waukegan Fire Marshal Steven Lenzi said the two missing employees were unlikely to have survived the blast.
Lenzi said that the rescue operations were halted and that the teams would not continue the search until the remaining parts of the plant had been demolished.
The investigators did not determine the cause of the explosion.
