A dead mouse caused nearly 200 pupils from two North Motherwell schools to be evacuated last week.
On Friday a member of staff at Clydeview School in Magna Street thought they smelled gas on their arrival at work and raised the alarm.
Clydeview pupils were starting the day with a visit to North Motherwell Parish Church and were told to stay there, while youngsters from the adjoining St Bernadette’s Primary were decamped to Logans Primary.
Gas engineers investigated, but found no evidence of a gas leak and declared the building safe, allowing pupils to return to class before lunchtime.
The smell was later thought to have been coming from the body of a dead field mouse discovered under the photocopier.
A spokesman for North Lanarkshire Council said: “Clydeview and St Bernadette’s were temporarily evacuated following reports of a strange smell.
“As a precaution gas engineers were called and, while they noted a gas-like smell, they confirmed the buildings were safe.
“Pupils and staff returned to their schools a short while later.
“The smell is believed to have come from a decomposing field mouse under a photocopier.
“While it’s one of those quirky incidents which take place from time to time, it’s important to note that everyone did what they were supposed to do and the safety of our pupils came first.”
There is no concern of an infestation at the school.
Field mice can get into buildings through very small holes. In 2007 a Massachusetts court building was evacuated when the smell of a dead mouse was mistaken for a gas leak.