Normal operations have resumed at Pearson International Airport after a fire at Terminal 1 on Sunday evening.

The fire broke out in a duty free store at the U.S. departures area of Terminal 1 around 6:30 p.m., causing the cancellation of all flights to the U.S. scheduled to depart from Terminal 1.

The fire was quickly extinguished, but a significant amount of smoke lingered in the area for several hours.

Airport officials were advising travellers heading to the U.S. on Monday to check their flight status before they leave for the airport.

“At this time, the cause of the fire is currently under investigation and we cannot speculate,” The Greater Toronto Airport Authority’s Maria Ganogiannis told CityNews. “Both Terminals 1 and 3 are operating normally, including Terminal 1 US departures, although some delays are still possible given yesterday’s events. Airlines are working diligently to rebook passengers who were impacted. We recommend passengers contact their airlines with any questions regarding delayed or cancelled flights.”

Good morning. Due to numerous U.S flight cancellations yesterday, we are anticipating a very busy morning for U.S departures. As always please check your flight status with your airline or at https://t.co/sCj5fDvHJ1 — Toronto Pearson (@TorontoPearson) March 18, 2019

Watch video of the scene inside Pearson Airport

The area was evacuated and international and transborder screening was stopped while the area was being cleared.

Peel paramedics said they treated several patients on scene for smoke related injuries and one woman was transported to a local emergency room in stable condition. Peel police confirmed no other major injuries were reported.

Passengers posted on social media that arriving flights were unable to deplane for several hours.

One passenger told CityNews her plane from New York City had been waiting on the tarmac since 7 p.m. and the captain decided to dip into the next flight’s food supplies in order to keep passengers comfortable during the extended delay.

She said passengers were initially told they would be bused to Terminal 3 to go through immigration processing, but Terminal 1 was reopened around 10:15 p.m. and her flight was allowed to disembark. Passengers were processed through customs at Terminal 1 shortly after.