LAPLACE, La.―Along Interstate 10 where the Mississippi River threads from Baton Rouge to New Orleans, ever-expanding petrochemical and other industrial projects have long been fought by environmental activists, who have saddled the stretch with the disputed moniker “Cancer Alley.” Now the Biden administration is opening a new front in the war -- against a proposed expansion of the sector in St. John the Baptist and St. James parishes known to Louisianians as the River Parishes. Under its stated aims of “equity” and “environmental justice,” the Environmental Protection Agency is trying to block state-issued permits for two new complexes – while...