Alberta’s oil-sands producers are aiming for a speedy ramp-up of lost production north of fire-ravaged Fort McMurray, easing market fears that emergency shutdowns of more than one million barrels a day could extend indefinitely.

Some facilities have already begun pumping crude at reduced rates, and others could start production within 24 to 48 hours of a decision to resume operations, Suncor Energy Inc. chief executive officer Steve Williams said after meeting with Alberta Premier Rachel Notley on Tuesday.

“Some will be more difficult and could be a week or two,” Mr. Williams told reporters in Edmonton, speaking on behalf of the industry. “The most difficult will be the ones we haven’t been able to get into to see yet, which are down south of Fort McMurray, where the fire actually went across the plant.” Those include Nexen Energy ULC’s Long Lake operation and Athabasca Oil Corp.’s Hangingstone plant, officials said.

To the north, Royal Dutch Shell PLC has partially restarted production at its Muskeg River and Jackpine mines, which the company shut down as wildfires intensified last week. They have capacity of 255,000 barrels a day.

Syncrude Canada Ltd. said on Tuesday it restarted an 80-megawatt power-generation unit at its Aurora mine, an initial step toward boosting production that also provides stability to the local grid, a spokeswoman said. The facilities were shut down over the weekend because of smoke.

The industry is grappling with minor damage to some electrical systems, but the fear that a large chunk of Canada’s production would be offline for an extended period now looks less likely. “We don’t believe at the moment that the electrical infrastructure issues are going to be big enough to stop the industry ramping up,” Mr. Williams said.

Suncor, which had shut down its base operation as conditions deteriorated last week, has said it could ramp up production fairly quickly once it is safe to do so.

Some industry analysts, however, cautioned that it could still take between two and four weeks for major operations to reach full capacity. A big unknown remains the impact on staffing levels following the mass evacuation of nearly 90,000 residents of the northern city last week.

“If the expectation is that there’s no key damage to production, then I think that those are the next things we’re really interested in looking at before we can say that production’s coming back online,” said Michael Tran, commodity strategist at RBC Capital Markets in New York.

Shutdowns at major plants expanded this week, even as the the direct threat from flames subsided north of Fort McMurray. Officials said Tuesday the fire had grown over nearly 230,000 hectares, but that it had shifted east to within about 30 kilometres of the Saskatchewan border.

On Monday, Norway’s Statoil ASA halted production at its steam-driven Leismer, Alta., project until related processing terminals reopen. The project produces about 20,000 barrels of oil a day.

Imperial Oil Ltd. has also shut down its much bigger Kearl bitumen mine, citing unspecified logistical constraints. The company offered few other details late on Monday, saying a restart would depend on a host of factors. It stressed there was no damage to the assets. A spokeswoman declined further comment. The project had produced 194,000 barrels of bitumen a day in the first quarter.

Meanwhile, Enbridge Inc. said on Tuesday that some of its facilities had sustained “limited” damage, although its two regional terminals were largely unaffected by the blaze. A spokesman said damage was limited mostly to above-ground valve sites along pipeline corridors. Even so, the company said its Cheecham storage facility and related pipelines remain shut down, and that it is assessing available power needed to restart the operations.

“We’re working collaboratively with our customers, provincial and local governments and the regulator to return our pipelines to service as soon as we are safely able to do so,” CEO Al Monaco said in a statement.

Inter Pipeline Ltd., which had briefly shut down a portion of its Alberta pipeline system last week, said on Tuesday that the lines were operational and they did not sustain any fire-related damage. The company said it did not anticipate a financial hit from the disaster.

However, two of its big customers remained offline as of Tuesday, with no restart in sight. They include Imperial’s Kearl mine and Husky Energy Inc.’s steam-driven Sunrise plant, where production was suspended last weekend. Both projects receive bitumen-thinning diluent on Inter’s Polaris system.