Project One was set to become Europe's most environmentally friendly steam cracker, based on technology specifically developed to run on green hydrogen in the future and can therefore be carbon-free. Initially, the facility would have run on ethane until sufficient hydrogen quantities become available. By using ethane as feedstock instead of naphtha, it is already possible to produce more ethylene while lowering CO₂ emissions. According to Ineos, its construction is the largest investment in the European chemical sector in a generation. The plant would have the lowest CO₂ footprint in Europe, three times lower than European crackers on average.

Ineos has been working on the project for five years. The permit application was initially approved by the Province of Antwerp in December 2021 and, following an appeal, confirmed by the Belgian Minister of the Environment, Zuhal Demir, in June 2022. On December 15, 2022, a symbolic sheet pile wall for Project One was lowered into the ground in the Port of Antwerp. In mid-February 2023, Ineos announced that the €3.5 billion financing had been secured and that commissioning was planned for 2026. In early June, the chemical company received environmental approval for the cracker from the Flemish government. The neighboring Dutch provinces of Zeeland and Noord-Brabant, as well as 14 NGOs, had objected to the permit. The Flemish government must now reconsider the application within six months.

In a statement published on the company's website, Ineos said it was "disappointed with the decision of the Flanders Permit Disputes Council to revoke the permit for Project One". In consultation with stakeholders and advisors, the group is now reviewing the decision to understand it and consider options.