Federal investigators believe that a dropped thermos may have been responsible for the 2017 bus crash that killed three people and injured 16 others in Flushing, Queens.

According to investigators, Dahlia tour company bus driver Raymond Mong was traveling at 60 miles per hour—more than twice the legal limit—when he ran a red light and slammed into an MTA bus on Northern Boulevard. Mong, who'd previously been fired by the MTA for a drunk driving offense, was killed in the crash, as was pedestrian Henry Wdowiak and a passenger on the city bus, Gregory Liljefors.

In their final report on Thursday, the National Transportation Safety Board cleared Mong of any wrongdoing, saying they'd "found no evidence that the motorcoach driver’s experience, training, route familiarity or pre-crash activities were factors in the collision."

But investigators did note that they'd found a metal thermos near the bus's pedals, which "could not be ruled out as a possible cause" for the fatal collision. In audio recovered from the scene, metal rattling could be heard as the bus gained speed, followed by Mong uttering a "single-word remark."

The NTSB also determined that the bus accelerated from 30 mph to 60 mph in about 90 seconds leading up to the crash, and that the brake light was not activated. A re-enactment of the scenario determined that it was possible to position a similar thermos in a way that caused runaway acceleration and prevented braking.

Still, the safety board did not definitively blame the misplaced thermos for the fatal crash: “The NTSB concluded that though an obstructed brake pedal could not be discounted as a factor in the crash, it also could not be determined as causal to the crash."

A spokesperson for the Federal Motor Carrier Safety Administration said the industry's "regulations are quite explicit that the driver is responsible for the safe operation of the commercial motor vehicle at all times."

Following the fatal incident, several local politicians called for stricter regulations over the charter bus industry, including more scrutiny into operators' driving records. Those bills died in Albany last session.

Since then, Dahlia tour company has reportedly racked up numerous violations in multiple states, including for driving significantly over the speed limit and lying about its drivers' past experience.

Additional reporting by Stephen Nessen.