Hawaiian Airlines plane makes emergency landing due to smoke in the cabin; 7 hospitalized

Thick, white smoke filled the cabin of a Hawaiian Airlines flight to Honolulu on Thursday, forcing the jet to make an emergency landing and sending seven people to the hospital.

Hawaiian Airlines flight HA47 from Oakland to Honolulu declared an in-flight emergency "shortly" before reaching its destination of Daniel K. Inouye International Airport at 11:36 a.m. local time, according to the Federal Aviation Administration. The Airbus A321 "landed without incident."

However, passengers were forced to choke their way through a smoky last 20 minutes of the flight, and then evacuate the aircraft on inflatable slides.

"Scary last 20 minutes of our flight," one passenger posted on Instagram, showing a photo of the plane taken on the runway with its slides deployed. "Mahalo Hawaiian Air getting us home safely."

There was smoke in the cockpit, cabin and cargo hold of the flight, according to the airline. Emergency crews met the plane as soon as it landed, with passenger photos showing a dozen emergency vehicles on the runway after its landing.

Hawaiian Airlines blamed the smoke on an isue with the plane's left engine.

"We have since determined that a seal failed in the aircraft’s left engine, causing oil to leak onto hot parts of the plane’s engine and air conditioning pressurization system, resulting in smoke in the cabin," it said. "The performance of the engine was not affected, and the Airbus A321neo flight landed without incident on runway 4R."

Seven people were transported to the hospital due to "smoke-related symptoms," the airline said in its statement.

"We sincerely apologize to our passengers for this incident and thank them for their cooperation in the evacuation," Hawaiian Airlines said in a statement. "We are working with airport officials and first responders to support our passengers and respond to this event."

The uninjured passengers were bused to the terminal from the runway before being allowed to go on their way.

The FAA is still investigating the incident.

ABC News' Sabina Ghebremedhin, Alex Stone and Amanda Maile contributed to this report.