CHICAGO (CBS) — Five firefighters and a resident of a South Side home were taken to hospitals today – because of noxious chemicals on the scene of a fire.

The fire started at about 11:15 a.m. at 8104 S. Campbell Av., and appeared to be a furnace fire, according to the Fire Department. The fire was extinguished, but when firefighters went to open windows in the building to ventilate, they discovered chemicals in a bathtub, which caused respiratory distress.

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Five firefighters and one civilian were taken to various local hospitals for treatment, according to the Fire Department. All were reported in stable condition.

The 67-year-old homeowner told Newsradio he had put bleach and water into a bathtub to soak overnight so he could clean it.

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A fire department spokesman said ammonia was also involved.

The homeowner said he’s not sure how much damage was done by the furnace fire.

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Another firefighter was hospitalized after hurting his hip during the fire. His condition was also stabilized.