Officials are investigating after some transit users reportedly felt ill while on the same bus in Surrey.

RCMP and Transit Police are looking into the possible suspicious hazmat incident on Sunday.

Emergency crews were called to 96 Avenue and King George Boulevard where the bus was stopped. Four passengers onboard had told the driver they felt sick.

Witnesses said the passengers may have been exposed to an unknown substance, but no evidence of any hazardous material was found.

The affected passengers were treated and released at the scene.