A supermarket in the Exchange District had to be evacuated Tuesday morning after a fire started behind the building.

Fire crews said the blaze broke out behind the Sun Wah Supermarket at the corner of King Street and Henry Avenue around 9:30 a.m.

Crews said the fire appeared to have started in a dumpster before spreading near the outside of the building.

The fire chief on scene said some homeless people may have been living behind the dumpster and their belongings may have caught fire.

Traffic had to be re-routed while crews fought the blaze.

The cause is still under investigation.