– Canada has responded to a deadly train explosion in Quebec by setting new emergency requirements for railway companies, including having at least two employees operating shipments of dangerous goods.

Trains that carry such goods can no longer be left unattended on a main track, the Transport Department said in a statement from Ottawa on Tuesday. The rules also outline stronger policies about setting brakes and guarding against unauthorized entry to locomotives. Additional measures are a “distinct possibility,” Gerard McDonald, an official at Transport Canada, told reporters.

“The disaster brought to light several industry practices which have caused some concern,” McDonald, assistant deputy minister for safety and security at Transport Canada, told reporters on a conference call. “Given that, with an abundance of preoccupation, we thought it should be prudent to implement these measures now.”

The temporary directive came as investigators seek clues into what caused a Montreal, Maine & Atlantic train loaded with crude oil to roll from its parking spot into Lac-Megantic, Quebec on July 6, creating a massive explosion that killed 47 people and leveled much of the downtown. It was the worst rail disaster in Canada in more than a century.

The train, which had a crew of one, was left unattended overnight near the town. McDonald declined to comment on the investigation of the crash.

The emergency directive will expire in December, and the government will ask railways to develop new permanent rules before then that reflect the new directives, McDonald said.

Cleanup crews in Lac-Megantic are still working to recover 1.5 million gallons of crude oil from the spill, Quebec’s environment ministry said yesterday in a news release. The train contained about 7.2 million liters of crude at the time of the derailment, the government said.

Separately, a Minnesota-based crude oil terminal operator has been added as a defendant to a lawsuit brought by the Montreal-based Consumer Law Group and other law firms on behalf of victims. Attorneys also moved to make the suit a class action.

Dakota Plains Holdings, based in Wayzata, loaded the leased tank cars with oil at its New Town, N.D., rail terminal. The company said it had no comment.

The suit, originally filed July 15 in Quebec Superior Court against the railroad and its owners, was amended Wednesday to allege that Dakota Plains, and other companies that sold and purchased the oil also were negligent in the accident. The suit seeks damages, including punitive penalties, for anyone in Lac-Mégantic who suffered a loss.

Staff writer David Shaffer contributed to this report.