According to Official Guinness Records,
The fastest mile in a fireman's uniform is 6 min 8.46 sec, and was achieved by Andrew Drobeck (USA) at the Missoula Mile, in Missoula, Montana, USA, on 17 June 2017.Andrew attempted this record to bring more publicity to the fire department and to raise money for prostate cancer awareness.
For a complete list of 2017 records, please visit 2017 Guinness Records in United States.