A judge has begun hearing arguments that could determine the fate of more than $431 million destined for victims and creditors of the 2013 train disaster in Lac-Megantic, Que.

Lawyers for Canadian Pacific Railway — the sole firm accused of responsibility in the rail disaster not to participate in the settlement offer — are in court today arguing the process is illegitimate and unfair.

CP is arguing that since MMA was a rail company and under federal jurisdiction, Federal Court, not Quebec Superior Court, is the proper venue for hearings.

It will also argue by freeing other firms of legal liability, it won't be able to counter-sue them if those companies decided to take CP to court to recoup the settlement sums they gave.

All other companies have contributed into a settlement fund and those firms would be released from legal liability in the U.S. and Canada and permanently removed from the class-action if a Superior Court Justice Gaetan Dumas approves it.

While CP doesn't dispute that families of the victims deserve compensation, the company argues it is not one of the companies responsible for what happened when a runaway train owned by now-defunct Montreal Maine and Atlantic Railway Limited (MMA) derailed and exploded in Lac-Megantic's downtown.

At least two dozen lawyers representing various companies and stakeholders are attending the hearing today in a large courtroom in Sherbrooke, Que.

The $431.5 million offer was accepted unanimously by creditors and victims in Lac-Megantic on June 8.

A lawyer who launched the class-action says the process will go ahead against CP if the company refuses to be part of the settlement fund.