As of 2021,[update] it was the fourth largest chemical company in the world, with additional operations in fuel, packaging and food, construction, automotive, pharmaceuticals, textiles, and professional sports.

[6] In 1992, Inspec was formed by Jim Ratcliffe, previously a director of the U.S. private equity group Advent International, and by John Hollowood, for the purpose of executing a management buy-in of British Petroleum's (BP) chemicals arm.

The two most notable of these were Innovene, the olefins and derivatives and refining subsidiary of BP, in October 2005 for $9 billion,[15] and ICI's commodity chemicals business in 2001.

It combines Ineos's refining interests at Grangemouth, Scotland, and at Lavéra near Martigues, France (about 30 miles west of Marseille), with PetroChina's access to upstream raw materials.

[21] On 23 October 2013 Ineos announced the closure of its petrochemical plant in Grangemouth, Scotland,[22] following a dispute with the Unite trade union over pensions and an attempt to impose a wage freeze and new contract on the workforce.

However, by 25 October 2013 the union capitulated to the closure threats and agreed to all Ineos's demands meaning the plant would stay open and strike-free for three years.

[24] In April 2017, Ineos reached an agreement to buy the Forties pipeline system in the North Sea from BP for $250 million.

[25] Towards the start of 2019, in the wake of British MPs rejecting Theresa May's Brexit Deal, the company chose to fund a €3bn investment (£2.6bn) in petrochemical production in Antwerp, Belgium.

Ineos set up new plants to produce it using key ingredients the company had used to manufacture polymers, and provided it free to hospitals.

[31] In January 2021, it was announced that Ineos was to donate £100 million to Oxford University for a new research institute for tackling antibiotic resistance.

[40] Ineos announced in July 2021 it was investing £25m in HydrogenOne Capital Growth, a fund that was aiming to raise £250m and float on the London Stock Exchange.

Later that month it was reported that PetroChina was unhappy with the return on the billion dollars cash they had paid for a 50% stake in the Grangemouth and Lavera refineries.

The request came a year after Sir Jim Ratcliffe, who is said to be the UK's third-wealthiest person, relocated to Monaco, apparently for tax reasons.

[44][45] In November 2023, Petroineos revealed plans to begin the work necessary to convert its operations at Scotland's only oil refinery, Grangemouth, into a business that imports finished fuel products, by 2025.

No formal decision on the date of the transition to refinery to import terminal has been taken by the company, but it is reported that the announcement was attributed to the challenges faced due to global market pressures and the shift in demand for the types of fuels produced at Grangemouth.

[49] Ineos Automotive Ltd. was formed in 2017 to develop and manufacture an off-road utility vehicle, intended as a "spiritual successor" to the Land Rover Defender, under the codename Projekt Grenadier.

[50] In September 2019, it was initially announced that vehicle, now officially named Ineos Grenadier, would be manufactured in two new factories in Estarreja, Portugal (chassis and body) and Bridgend, South Wales (final assembly), with powertrains supplied by BMW.

[53] The announcement was condemned by Welsh Labour MP Chris Elmore, who contrasted the decision to relocate production to the European Union with Ratcliffe's support for Brexit.

[56] Ineos has been accused by some of buying assets then cutting costs through the introduction of new working practices, lower wages, and terminating pension schemes.

[57][58] Stephen Deans, convener for Unite union at the Grangemouth plant where he worked, and also head of the Falkirk branch of the Labour party, was suspended from his employment at Grangemouth by Ineos in the summer of 2013, while they investigated what they said were accusations he had been using company resources for political campaigning; related to recruitment of Unite members in Ineos workforce to the local Labour branch, where the selection of a new parliamentary candidate was taking place after the de-selection of Eric Joyce.

[64] The next day the Unite union reversed its position and agreed to Ineos's proposals, which included an undertaking not to strike for three years.

[66][67][68] In March 2016, Ineos's Port of Runcorn ChlorVinyls facility was found guilty of releasing caustic soda into the Manchester Ship Canal.

Beyond elite sport, INEOS supports The Daily Mile Foundation — a running initiative for school children to get them moving for 15 minutes a day.

INEOS Chairman, Sir Jim Ratcliffe also funds sustainable conservation through a fishing project in remote North East Iceland, seeking to reverse the decline of the wild North Atlantic salmon, and funds ecotourism and conservation work in Tanzania through a joint venture with Asilia Safaris.