The plane was arriving from Montreal and had landed, before colliding with the vehicle from the Port Authority of New York and New Jersey, which runs the airport.
The fire engine was responding to a United Airlines aircraft that had “reported an issue with odour”, Garcia said during a news briefing.
The aircraft – a CRJ 900 model, carrying 72 passengers and four crew members – suffered significant damage.
All on board the plane have been accounted for, Garcia said, while adding that the sergeant and police officer who were inside the firefighting vehicle were in a stable condition in hospital “with no life-threatening injuries”.
“I visited them both in the hospital, as has the chairman, and they were able to speak and we’re notifying their families,” said Garcia.
Video footage on social media showed the aircraft, which is operated by Air Canada’s regional partner Jazz Aviation, coming to a rest with its nose upturned.