Seven firefighters were rushed to the hospital after battling flames in East New York. 

The fire started in a kiln stove inside Belmont Metals on Belmont Avenue at around 1 a.m. 

The firefighters were all taken to Kings County Hospital for smoke inhalation and chemical exposure after coming into contact with an unidentified substance. Each firefighter has since been treated and released. 

Investigators say that hazmat crews were brought in to check out the substance, which was burning in the fire.