Redcar's blast furnace will be re-lit this weekend, having cost £1bn and creating 1600 jobs.
The blast furnace was mothballed in 2010 and people on Teesside were told steelmaking in the area had gone forever.
Steelmaking has been on Teesside since the 19th century, but struggled in recent years as demand for British steel decreased.
The final mothballing of the plant in 2010 led to Labour losing its safe seat in Redcar as workers said the government had not done enough.
Vera Baird, who was MP at the time, said: "One minute the steelworks is selling steel and is at absolute maximum production, and the next minute it's completely useless and the world has no purpose for it.
"However oppressed Redcar got, it always had its steel, and that was being cut away."
Dave Cocks, who was manager of the blast furnace for 30 years, said "At the time that we pressed that button to turn the blast furnace off there were tears in the control room. Guys of 30 or 40 years experience were very upset by everything that was going on and I'm sure there was a great deal of despair among those that thought it was the end of their working careers."
However, last year the Thai firm SSI signed a £320m deal securing a future for steelmaking on Teesside. It will concentrate on the growing economic markets in Asia.
Phil Dryden, the President of SSI UK, said "I'd like to believe what we are creating is something that will be around for decades to come. Automobiles and white goods in Thailand but eventually into Cambodia, into Vietnam, into Burma.
"If we can show capabilities that have never been shown before I think the world will start to wake up and say, okay what's happening on Teesside."
Follow updates on this story.