Several roads around a new Tesco building site in Stoke-on-Trent were closed for almost four hours due to a suspected gas leak.
The site, next to Clough Street, was evacuated and construction work suspended while engineers replaced cracked pipework.
Nearby roads were reopened at about 1500 BST, a spokesman said.
Tony Fletcher, from Tesco, said the suspected leak and repairs would not delay the planned opening in November.
Staffordshire Fire and Rescue said fire crews attended the scene as a precaution.