Customers and staff at a Portsmouth branch of Tesco were evacuated this morning after a gas detector went off.
Police, ambulance and fire services were called to the superstore in Clement Attlee Way shortly after 7am.
The car park of the North Habrour store was cordoned off.
A Hampshire Fire and Rescue Service spokesman said a gas detector inside the store had gone off, and fire crews were sent inside.
He said: ‘We investigated it and we found no sign of gas.’
Two engines from Cosham, and one each from Winchester and Portchester were called out.
Four firefighters wearing breathing apparatus were sent inside the store to investigate.
The stop message from fire crews came in at 9.13am.
Speaking earlier, a spokesman for Cosham Fire Station said the crew were called out at 7am to a ‘hazardous material’ incident.
A parent of a staff member telling The News there had been reports of a methane gas leak.
Police cars were parked at either end of the street to stop traffic entering the road.
The area has now been fully reopened.