Some fire stations are at "crisis point" because of a lack of retained firefighters, say fire bosses. Around a quarter of stations in Lincs have been out of action recently because of a shortage in cover.
Lincolnshire fire service is now appealing for people to become retained firefighters after warning that response times could be hit.
Recruitment manager Nick Davis said: "This delay could literally mean the difference between life and death."
On one day this week nine out of the county's 38 fire stations were unavailable for cover because there were not enough crew members.
Mr Davis said it means crews from the next nearest fire station being called out instead.
"The crews at some stations are doing everything in their power to keep their fire engines on the run, available for calls, but they are stretching themselves to the absolute limit," he said.
"There's a breaking point for everyone, everyone needs a day off."
Delay factor
The county's fire service is struggling to fill retained firefighter positions because it predominantly needs people who can provide cover during the day.
"The trouble is people have to work in their communities and there's less and less work in the smaller villages and towns and people are travelling to their main careers," said Mr Davis.
"We will always get an emergency fire crew to the incident, but there will always be that delay factor because of the size of the county.
"We are certainly at crisis point at some stations."