An investigation is underway following an apparent explosion underground near Calgary’s BMO Centre Thursday morning.

It happened just before 8 a.m. Thursday at Macleod Trail SE and 14 Avenue SE.

Five workers were hurt after the industrial incident near a manhole.

EMS public information officer Stu Brideaux says four of them were taken to hospital in stable, non-life threatening condition.

At this time the scene does remain in care of police and OHS [Occupational Health and Safety] officials,” he added.

The fifth received treatment at the scene.

Macleod Trail was closed between 14 Avenue SE and 17 Avenue SE for several hours, but has since reopened.