Parkland County announced late Monday evening that a third controlled burn was needed to completely clear propane spilled following a train derailment over the weekend near Gainford, Alberta.

The news came after CN Rail initiated a controlled burn late Monday evening – officials said five cars still contained propane.

At about 7:15, officials said crews were able to check whether their efforts to clear up the propane had been successful – and one car still contained the fuel, so CN had planned another burn to take place after 9 p.m.

It’s hoped the burns will make it possible for the evacuated residents to return home.

Earlier Monday, the 126 evacuated residents heard it wasn’t clear when they would be allowed back home, after being evacuated early Saturday morning following the derailment, and the explosion and fire that followed.

Officials originally hoped to have evacuees returning home within a few days, but announced Monday that a controlled burn to get rid of propane fuel spilled in the derailment had not been as successful as hoped.

Crews started the fire to burn off the fuel Sunday night – but said Monday that there was still fuel in the rail cars when they were checked later on.

“We had hoped the exercise would burn off all the propane in the cars so that we could move in, remove the cars and allow people to go home,” Warren Chandler, a senior manager with CN Rail said. “Unfortunately, when we went to inspect the cars at 11 p.m. last night, we found that all the cars had not vented their propane.”

The derailment happened at about 1 a.m. Saturday, along Highway 16 and Range Road 61, near the Hamlet of Gainford.

Officials said four of the cars were carrying crude oil, and nine were carrying propane.

As a result, an evacuation order was put in place for Gainford and anyone living within a two kilometre radius of the derailment.

On Monday afternoon, officials announced a second vent-and-burn process, similar to the procedure used Sunday, would be carried out again between 4:30 and 6:30 p.m.

Parkland County officials said residents with questions about the burn can call CN’s information line at 1-877-621-5456, and to call 780-968-8400 for information regarding the evacuation.

In addition, Highway 16 west of Range Road 50 remains closed – traffic is being rerouted north along Secondary Highway 765, west along Secondary Highway 633 and south on Secondary Highway 757.

With files from Sarah Richter and Laura Tupper