Roger Johnson, a current presenter at the programme, said: “Beccy was courageous in so many ways.
“In the way she faced her illness, of course, but she also had the courage to walk away from a successful TV career to retrain as a firefighter.
“She wanted to make a difference and she excelled at that, too.”
He added his thoughts were with her family.
The firefighter, who was a member of Lancashire Fire and Rescue service’s Red Watch in Blackburn, followed in her father’s footsteps when she joined the service.
She also studied for an MSc at Bournemouth University’s Disaster Management Centre.
The fire service said it was “deeply saddened” to hear the news, adding: “Beccy was a dedicated and courageous firefighter who served with professionalism and compassion.
“She was an enthusiastic and warm person who became an inspiration to many.”
Lancashire’s chief fire officer, Justin Johnston, told the it was an “incredibly sad day”.
He said Ms Barr, who got a distinction in her apprenticeship, was an “amazing professional, wise and warm” and passionate around firefighting techniques and developing the service.
“She made a really big impact in her short time – five years – with us,” he said.
He said she was “such an active person” who “made a really positive impression wherever she went”.
“Our hearts go out to her family, her friends and her work colleagues here at Lancashire Fire and Rescue Service.”
