The Sadara joint venture of state petroleum firm Saudi Aramco and US firm Dow Chemical has started up the last of 26 units comprising the world’s largest integrated chemicals complex to be built in a single phase.

Sadara says the 200,000 tons/year unit will produce the Gulf region’s first toluene diisocyanate (TDI), a chemical that is mainly used in the production of flexible polyurethane foam. This is particularly in demand for making car seats and furniture.

The $20bn Sadara...