A 15 year industrial gas deal has been agreed to help safeguard the future of steelmaking on Teesside.

Redcar iron and steel firm SSI, and Middlesbrough-based gas supplier BOC have signed one of the UK's largest ever gases contracts to keep the fires burning in Teesside blast furnace.

To support the deal, BOC, a member of the Linde Group and the biggest industrial gases company in the UK, has spent £25m on a major revamp of its Teesside site. The two-year investment programme is now complete and includes an upgrade and expansion of the three existing Air Separation Units (ASUs) which supply oxygen, nitrogen and argon, and re-engineering the existing pipeline systems to SSI's Redcar site. Specialist control equipment has also been designed and built for the blast furnace.

Bosses from both companies will this morning join local business leaders and dignitaries at a ceremony at BOC's Teesside plant to mark the start of the 15-year supply agreement.

More than eight million tonnes of steel have been made in Redcar since SSI rescued the famous works from mothballing and restarted production in April 2012. The business has yet to show a profit, however, as the global price for steel has remained stubbornly low, while the cost of keeping the plant afloat has required its Thai owners to inject hundreds of millions of pounds to keep the business afloat.

SSI regards today's announcement as a significant vote of confidence from one of its key suppliers, and sends a strong message that North-East steelmaking is here to stay.

Cornelius Louwrens, UK business director and chief operating officer of SSI Steel UK said: "I am delighted to have worked with BOC on concluding this important contract, which will help us take SSI UK forward.

"This supply arrangement is key to our long term plans to maximise our steel slab production capability and satisfy the requirements of our parent company in Thailand and other strategic global customers".

Sue Graham Johnston, managing director of BOC, said: "BOC has been established in Teesside for many years and we are committed to supporting the area's vital industrial base. Our new partnership with SSI UK is important for jobs and prosperity in the region as well for the UK's wider industrial sector and I am confident that the investment we have made in our Middlesbrough site will also bring long-term benefits to both companies."

The significant investment positions BOC's Middlesbrough's site as the key location for industrial gases in the region, the firm said.

more than eight million tonnes of Teesside steel has left the plant for clients in Thailand, Europe and the US.