Kamloops Walmart managers were forced to usher hundreds of customers and staff out of the store on Tuesday when excavation workers outside the store struck a gas line.

Shortly before noon, construction crews working outside on the store's property informed Walmart manager Tim Labermeyer that natural gas was filling the air after a line was severed.

Labermeyer immediately evacuated 300 customers and staff and alerted the Michaels store next door, whose manager also evacuated those inside.

"We just wanted to err on the side of caution and get everybody out," said Labermeyer.

Two Kamloops Fire Rescue units responded to the emergency call along with B.C. Ambulance paramedics and RCMP cruisers, which quickly blocked off every entrance to the parking lot servicing Walmart and several other businesses.

A strong odour of natural gas hung in the air while Fortis crews assisted by Fire Rescue shut off the gas.

Prolonged or intense exposure to natural gas could lead to symptoms of poisoning, but the threat was minimized since the leak was in the open air and dissipated quickly, said Fire Rescue Asst. Chief Mike Adams.

Adams said his crews appreciated the store managers' response nonetheless.

"All credit goes to them for being pro-active," said Adams.

The situation was under control and emergency personnel were gone within an hour.

It's not yet clear why crews weren't aware the line was buried there. The contractor behind the excavation followed proper protocol by getting plans for underground utilities, according to Adams. Fortis is investigating, he said.

Labermeyer said the incident did slightly impact business, but that wasn't a concern.

"It's minor when you put it in the big picture of things."