In a post on Facebook, the department said Efren Medina died while on duty last Saturday.
Efren was a newly-hired firefighter, working his first shift, the post said.
Fire Chief Tom Lackner told WLTV Efren died in his sleep after responding to a call.
“He was known for his long time passion for firefighting and his love of the fire service,” the department wrote.
In a GoFundMe post started to help Efren’s wife, his friend said the 21-year-old was “a wonderful brother, son, husband, and friend to all. He was very caring, cheerful, and hardworking. Efren was dedicated to working towards becoming a fireman and selflessly helping others also being an EMT.”