Bilfinger UK has won a six-year contract with Essar Oil at its Stanlow Refinery, which will provide work for 200 employees.
The deal covers a range of services, from electrical and mechanical work to painting and asbestos removal.
Stanlow, at Ellesmere Port in Cheshire, supplies 16% of all road transport fuels UK-wide.
Bilfinger UK said it comes after “many months” of working with Essar Oil to understand the “vision” for the Stanlow site.
The value of the deal has not been disclosed.
Bilfinger UK managing director Phill Maurer said: “This six-year agreement is testament to the exceptional work and safety performance delivered by the site team and represents a significant addition to our portfolio of support partnerships at major facilities across the UK.”
The refinery has 900 staff, an additional 800 on-site contractors and a further 5,000 people employed indirectly through the extended supply chain.
Jon Barden, chief operating officer at Stanlow, said: “I welcome Bilfinger UK as our lead partner for the delivery of mechanical, scaffolding, insulation, painting and electrical and instrumentation services at the Stanlow and Tranmere locations.
“We look forward to developing a successful long term relationship where both parties work collaboratively to deliver improvements in our collective safety and business performances to benefit our respective employees and owners.”
Bilfinger UK has around 4,000 employees across the country and is a subsidiary of the namesake industrial services giant, which is based in Germany.
The group has a separate offshore energy subsidiary, Bilfinger Salamis, based in Aberdeen.