AN investigation is under way after the second gas leak at a Hampshire superstore in just a month.

Staff and shoppers were evacuated from Asda in Totton at about 12.50pm yesterday after Freon, used to cool fridges and freezers, leaked from the plant room.

Four weeks ago ten people, including four firefighters, were taken to hospital when the same gas leaked following a small explosion when a compressor overheated.

Fire chiefs have now launched a fresh probe after yesterday's incident and plan to discuss safety practices with store managers.

Crews were called to the shop in Maynard Road after the leak activated alarms.

Shoppers were told to evacuate the building, which was then taped off.

Firefighters donned chemical protection suits and breathing apparatus to pinpoint the leak, traced to a faulty compressor valve.

Crews, who came from Totton, Lyndhurst and Redbridge, remained on the scene for more than two hours.

Staff were allowed back in at 3pm although the shop was expected to remain closed until the evening.

An ambulance was also called to the store as a precaution but no one needed treatment.

A store spokesman said: "There was a leak but no one was injured.

"It was not caused by the same equipment as last time.

"We have now started an investigation but all the usual procedures after the leak were followed."

Shopper Andrew Long, 38, from Bramshaw, said: "There were quite a lot of people in there.

"The alarms went off but nobody really knew what was going on.

"Then they announced that everyone should leave the building."

A spokesman for Hampshire Fire and Rescue Service said: "Almost certainly we will be speaking to them and there will be an investigation.

"If the investigation shows there is a problem implementing safety practices then we will certainly be having words with Asda, not just at a local level but maybe even higher up."

The ten people taken to Southampton General Hospital as a precaution following last month's incident did not need treatment and all returned home after a check-up.