A representative with CAL FIRE told ABC sister station KXTV in Sacramento the individual was suffering from a previous illness.
The first responder was an assistant fire engine operator with the Lassen National Forest, according to a spokesperson. He died on Saturday.
Three other first responders battling the fire have been injured.
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The Dixie Fire has burned more than 889,000 acres across five northern California counties, and is 56% contained, making it the second largest recorded wildfire in California history.
The video in the media player above is from a previous report.