MONTREAL -- An arbitrator says the firing last summer of Thomas Harding, the train engineer involved in the Lac-Megantic rail disaster, was illegal. He won't be returning to work, but he will get financial compensation.

Harding was acquitted in January 2018 of criminal negligence causing death.

He returned to work for Central Maine and Quebec Railway, which took over from the defunct Montreal Maine & Atlantic that operated the line at the time of the derailment. Harding went on sick leave and was supposed to gradually return to work as of July 5, 2018, but on June 27 he received a letter of dismissal.

The employer cited his involvement in the Lac-Megantic derailment and said the relationship of trust had been broken.

Harding's union filed a grievance, denouncing the fact his employer did not investigate the situation, as required under the collective agreement. Last week the arbitrator agreed and nullified the firing.

The engineer became the public face of the Lac-Megantic disaster after it was revealed he didn't apply sufficient hand brakes on the oil-laden convoy before retiring for the night.

The train began rolling downhill in the early hours of July 6, 2013. It barrelled into the town, derailed and exploded, killing 47 people and destroying part of the downtown.

The union asked that Harding be reinstated, but the arbitrator said that considering the circumstances a financial compensation was more appropriate. The amount has not been determined.