Some Calgary WestJet passengers bound for Houston on Sunday were accidentally exposed to de-icing spray, the airline has confirmed.

The plane was being de-iced on Sunday morning in preparation for a flight to Houston when some of the chemical fluid made its way into the air-conditioning system, airline spokesperson Lauren Stewart said in an email to CBC News.

The plane returned to the gate and emergency medical crews were called in to assess the crew and passengers.

WestJet says two crew members sought medical attention as a precaution and no passengers were injured.

"Paramedics did transport an adult female to hospital," EMS spokesperson Adam Loria said. "She was in stable and non-life-threatening condition."

Stewart says the fluid might have come in through an auxiliary power unit (APU).

"The APU has an inlet that must remain open when operating and we believe de-ice fluid migrated into the inlet even though de-ice crews are well-trained to keep fluid away from the inlet," Lauren Stewart said.

"A fulsome review is being conducted with our de-ice crews in YYC to learn what happened and to prevent reoccurrence. These findings will be shared amongst all of our de-ice crews across our network."

Passengers were booked on another plane 2½ hours later.