A Tesco store had to be evacuated in Hemel Hempstead this morning following a methane alert.
Staff and customers pushing trolleys had to leave the store in Jarman Park and gathered for a while in the car park before being told the store would remain shut.
The Tesco Extra Branch is still closed while the fire service attend the scene.
A Tesco Spokesperson said: “Our Tesco Extra store in Hemel Hempstead was evacuated this morning following a methane alarm.
“The fire service attended the store and we can confirm that no methane has been detected.
“We are grateful to customers for their patience and we hope to reopen the store later this morning.”