Part of Blackpool Victoria Hospital had to be evacuated after a fire.
The hospital’s outpatient ward had to be cleared after the incident broke out in a heating unit.
Around 150 patients had to be evacuated from the building.
Four fire engines from Blackpool, South Shore and Bispham attended the hospital at 1.10pm on Monday after a member of staff smelled smoke and raised the alarm.
The patients were taken outside for their safety.
Watch Manager Mark Warwick at Forest Gate said because of the smoke involved, it would have looked like a serious fire.
He said: Smoke was billowing out.
“It could have been much worse, but it didn’t cause too much damage.”
He said the patients were back inside within 45 minutes.
A spokesman for Blackpool Teaching Hospitals NHS Foundation Trust said the area was evacuated of patients, visitors and staff as a precaution.
The heating unit has removed.