He said the new investment package demonstrated Ineos and the UK government’s commitment to British manufacturing.
“It protects 500 high-value jobs, secures supply chains, and preserves the industrial capacity the nation needs,” he said.
“The support of the UK government is welcome as we work to deliver competitive and efficient low-carbon manufacturing for the UK, long term.”
In recent months there has been concern about the future of the UK petrochemical industry because of the rising cost of energy.
Last month, ExxonMobil announced plans to close part of the Mossmoran chemical plant in Fife by February, with the loss of up to 400 jobs.
The company said the high cost of energy at the plant, which also produces ethylene for the plastics industry, was partly to blame for the decision.
The UK government has warned high energy costs have caused problems for the chemicals industry across Europe.
It said about 40% of ethylene gas capacity has either closed recently or is at risk of closure.
