(CNN) -- The emergency rooms at two hospitals in Missouri were placed on lockdown Saturday after patients arrived complaining that they had been exposed to a chemical.
SSM DePaul Health Center in Bridgeton, Missouri, and St. Anthony's Medical Center in St. Louis, Missouri, admitted the patients and restricted access to their emergency rooms.
The patients were believed to have come to the hospitals after being exposed to the chemical at an industrial site in East St. Louis, Illinois, said Chief Jim Silvernail of the Mehlville Fire District. He described the chemical as a "power situation" that required contact to make the people sick.
SSM DePaul said its hospital went on lockdown about 3:30 p.m. CT.
Hospital officials said three people were admitted after coming in contact with a chemical that made them sick with respiratory problems. All three were listed in fair condition and showed signs of improvement.
Fifteen employees and one other patient who came in close contact with the patients have been decontaminated and kept for observation, the hospital said.
SSM DePaul said it expected to reopen in three to four hours.
St. Anthony's said "several" patients came to the emergency room. Initially, the entire hospital campus was restricted, but later only the emergency room was placed on lockdown.
St. Anthony's officials provided no information on the condition of the patients, and neither hospital had information on what the chemical might have been.
However, Silvernail said three patients had been brought to St. Anthony's. He said fire crews were attempting to determine what the chemical was.
CNN's Amanda O'Donnell contributed to this report.
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