Cardiac patients at a hospital were evacuated on Saturday after a blocked drain sent noxious gases into two wards.
Firefighters were called to Derriford Hospital in Plymouth, Devon and 40 patients were moved from wards on level eight of the Terence Lewis building.
Fire crews then unblocked the drain and used large fans to clear the affected wards of the smell.
A spokesperson for Devon and Somerset Fire and Rescue Service said patients were later returned to their wards.
"A foul smell had been reported coming from one of the drains and staff at the hospital were concerned that noxious gases may have been present," the spokesperson said.
"As a precaution, patients were moved to other wards in Derriford Hospital."
The hospital said: "Engineers will now work to investigate the cause of the blocked drain and try to ensure the problem does not recur."
