By Nia Williams and Eric M. Johnson

CALGARY, Alberta (Reuters) – Firefighters battling a wildfire that has threatened oil sands facilities north of Fort McMurray, Alberta, looked to cooler weather, a change in winds and the promise of rain to help them on Thursday.

A shift in wind direction from west to east is expected to push the fire back toward areas it has already burned, limiting its growth, wildfire information officer Travis Fairweather said on Thursday.

“That should hopefully result in a little less activity than we’ve seen in the last couple of days,” he said.

The fire, which hit Fort McMurray in early May, destroying entire neighborhoods, surged north on Tuesday, forcing the evacuation of 8,000 oil sand workers, destroying a work camp and prolonging a shutdown that has cut Canadian oil output by a million barrels a day.

Fairweather did not expect the fire to damage any oil sands facilities on Thursday.

The fire covered 483,084 hectares (1.2 million acres) as of Thursday morning, up some 61,000 hectares from the day before. Fairweather said cooler weather and the chance of rain on Thursday also would help contain the fire.

Some of the 90,000 evacuees who fled Fort McMurray as the massive blaze breached the city may be allowed to return as soon as June 1, officials said on Wednesday, if air quality improves and other safety conditions are met.

Some oil sands operations directly north of the city remained shuttered, although firefighters held the blaze back from Suncor Energy and Syncrude Canada facilities on Wednesday.

The fire destroyed a 665-room lodge for oil sands workers on Tuesday but officials said on Wednesday they were not aware of further industry damage.

Tuesday’s evacuations were a setback for producers, suggesting production may be suspended for longer than companies and analysts had previously anticipated.

The province’s plan to gradually allow residents back into the city offered hope but also trepidation.

“It’s exciting news but you are also scared to see what you get when you get back,” said Fort McMurray resident Ria Dickason, adding that she was concerned about smoky air.

The air quality health index, which usually stands between 1 and 10, hit 51 on Wednesday morning, before improving to 11.

“We won’t go back if it’s anything close to the levels it’s at now,” Dickason said. “My daughter has asthma so we are more alert to it.”

(Additional reporting by Allison Martell and Ethan Lou in Toronto; Editing by Bill Trott)