A garbage truck driver’s impairment was the likely cause of a deadly collision involving his vehicle and an Amtrak train at a crossing in Virginia, according to the National Transportation Safety Board (NTSB).

The incident occurred on January 31, 2018, about 11:16 a.m., when a 2018 Freightliner refuse truck driven by 30-year-old Dana Naylor attempted to navigate a highway-railroad grade crossing in Crozet.

Naylor’s decision “to enter an active grade crossing and his inaction when he encountered obstacles while attempting to cross the railroad tracks, most likely due to his impairment from the combined effects of the drugs marijuana and gabapentin,” said the NTSB in a report on the incident. Gabapentin is used to treat seizures.

The grade crossing is located on a curved segment of the track and is equipped with an active warning system consisting of flashing warning lights, bells, and gate arms that lower at a train’s approach.

One of Naylor’s two passengers, 28-year-old Christopher Foley, was killed in the collision. A second co-worker was severely injured. The NTSB said the lack of seat belt use by the truck’s inhabitants.

Following the crash, Naylor was acquitted of manslaughter. A second charge of DUI maiming was dismissed by a judge who ruled that the science on marijuana intoxication wasn’t settled.

The crash happened in January of 2018 as a chartered Amtrak train headed to a retreat at The Greenbrier resort in West Virginia. One trash company employee, 28-year-old Christopher Foley, was killed, and a second passenger was severely injured.