An earlier version of this article incorrectly characterized it as a new investment, when Exxon announced it more than four years ago. The news today is the start of the expansion project. It has been corrected.
Exxon Mobil Corp. XOM said Thursday it has started work on its biggest refinery expansion in the US since 2012 in the form of a $2 billion project at its Beaumont refinery, equivalent to adding a medium-sized refinery. The oil major said the move would increase capacity for transportation…