The 65m high Basic Oxygen Steelmaking Plant in Redcar was levelled with 1.6 tonnes of explosives.
There were three blasts over a seven-second period bringing down the 60,000-tonne structure.
The cost of demolition, construction and site remediation at the Teesworks regeneration site is forecast to be more than £180m in 2022-23.
Tees Valley Mayor Ben Houchen said: “Each demolition of the former steelmaking structures on this site is a bittersweet moment as they have played such a huge part in shaping our communities, people and identity for decades.
“While we remember our past, we must never lose sight of the reason we’re doing this.
“I made a promise to build a better future for the people of Teesside, Darlington and Hartlepool and today is another part of delivering upon that.
“We’re already seeing that just a few hundred yards away, with construction underway on SeAH Wind’s huge offshore wind manufacturing plant – a £400m investment already creating good-quality, well-paid jobs for local people.
“It’s soon to be joined by Net Zero Teesside and the 5,500 jobs that will be created just to build the £1.5bn power plant with carbon capture, utilisation and storage.
“We’re continuing to clear the way to bring more cleaner, safer and healthier industries of tomorrow, creating good-quality jobs for local people.”