CHICAGO (CBS) — Three workers were injured when a tank cleaning service building was destroyed in a fire and explosion, Wednesday morning in East Chicago.

According to Fire Chief Anthony Serna, firefighters were called to an explosion at TAC East, 2000 Gary Ave., around 7:22 a.m.

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There were five people working in the building and three suffered “flash burns” from chemicals in the air, Serna said. The workers were being treated for first, second and third degree burns on their extremities at Methodist Northlake Hospital in Gary.

Smoke billows from a building fire in East Chicago (Credit: Cathy Poppen)

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Plumes of smoke could be seen for 2 miles. Initial reports indicated the explosion occured in area of boiler room

The cause has not been confirmed but views from Chopper 2 showed extensive fire damage.

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TAC cleans semi-trailer tanks that haul different chemicals.