A massive fire erupted at Shell’s refinery in Rotterdam, in the Netherlands, causing a blackout and forcing the company to halt all loadings at least till Tuesday. The extent of the damage to the plant has yet to be assessed.

The source of the huge blaze that engulfed Shell’s Pernis facility, Europe's largest oil refinery, Saturday evening, has yet to be determined. Media reports, meanwhile, point to a short circuit as the most likely reason.

The power outage that crippled the refinery as a result of the fire rendered several units out of service, prompting the Royal Dutch Shell company to completely shut all operations.

“Shell is in the process of shutting down all the units at the site,” a company spokesman said, as cited by AFP. He added that the process might last for “hours, or even several days.”

Taking all “necessary precautions,” the company said it estimates that “loadings at depot Pernis will be interrupted until and including tomorrow.”

Firefighters succeed in dousing the flames by Sunday morning at around 6:00am [0400 GMT].

However, flashes at the plant could be still seen Sunday evening, as mangement decided to launch a flaring process to burn off excess natural gas in accordance with safety guidelines.

Shell's spokesman said the process is “completely under control.”

“There are strong flames during flaring. It's a dramatic sight. But it's just a controlled process,” the spokesman said, as cited by Het Financieele Dagblad.

“Several units are stopped and for security reasons we are burning off the gas that remained inside them,” he said.

Many photos and videos emerged on social media showing heavy flames and plumes of thick smoke billowing from the plant.

The Dutch authorities were quick to assure the public that the smoke contained no toxic materials but might contain soot. No injuries have been reported.

The facility is estimated to be capable of refining some 400,000 barrels of crude oil per day.