The Grangemouth refinery has now ceased processing crude oil, its owner Petroineos has confirmed.
The industrial site in central Scotland was the last oil refinery operating north of the border.
The local MP said Scotland “is a victim of industrial vandalism and devastation” as a result of the closure.
In September last year, the company said the refining activities would cease in 2025 as it transitions to become an import terminal for finished fuels.
The impending closure of the refinery, which first opened in 1924, led to fears for employment in the area.
In recent months, hundreds of workers have taken voluntary redundancy while a number of compulsory redundancies have also been made.
A significant report commissioned by the Scottish and UK governments, known as Project Willow, aimed to chart a future for the site in low-carbon energy.
But the report said this would require around £3.5 billion of private investment.
Petroineos has said the refinery is loss-making and has rejected claims from unions that the site could easily transition into a hub for producing sustainable aviation fuel.
Iain Hardie, regional head of legal and external affairs, said: “Grangemouth refinery is no longer processing crude oil.
“Petroineos has invested £50 million in creating a modern import and distribution terminal capable of receiving finished fuels by sea for onward distribution to customers around the country.
“From today, we will be importing all the products necessary to meet Scotland’s demand for transport fuels.”
He continued: “We would like to pay tribute to the workforce here.
“Our colleagues have shown incredible commitment, dignity and resilience during months of uncertainty regarding the future of this facility, through the consultation period, phased shutdown and the start of refinery decommissioning.”
Other parts of the wider Grangemouth complex, including the Forties pipeline system which links to the North Sea, will not be affected by the site’s closure.
MPs discussed the closure in the Commons on Tuesday.
Brian Leishman, the Labour MP for Alloa and Grangemouth, said: “Today is the end of over a century of refining at Grangemouth.
“Scotland once again is a victim of industrial vandalism and devastation, and I don’t want anyone in this chamber to dare mention a ‘just transition’, because we all know that the Conservatives when in power and the SNP currently in Holyrood did nothing to avert this catastrophic decision happening”.
Mr Leishman shook his head and shouted “not enough” as Energy Secretary Ed Miliband replied: “Grangemouth has a really important role in Scotland.
“What I would say to him and to others is this Government, as soon as it saw the situation it inherited, put money in to help the workers and has made this huge investment commitment of £200 million working hand-in-glove with the Scottish Government so we absolutely build a future in Grangemouth.”
Liberal Democrat MP Christine Jardine referred to remarks from Ineos chairman Sir Jim Ratcliffe, who said his company may have to pause investment due to high energy prices and carbon taxes.
Ms Jardine said: “Today there are warnings from Grangemouth that they may have to pause important projects to switch to greener and more sustainable energies because of what they describe as the soaring energy bills and the pressures of income tax.”
