A $300 million settlement that will reduce industrial flare pollution at two Louisiana chemical plants strengthens arguments that the federal standards governing such flares need to be overhauled, according to an environmental attorney. The recent settlement announced by the Louisiana Department of Environmental Quality and the U.S. Environmental Protection Agency will cut air pollution by more than 5,600 tons annually at petrochemical facilities in Texas and the Louisiana communities of Hahnville and Plaquemine. Dow Chemical Co. and two of its subsidiaries agreed to the settlement, which was filed in the Eastern District of Louisiana. A federal complaint alleged that the companies had “oversteamed” their flares, which are devices that destroy pollutants in waste gases vented by the plants. The result was excess pollution spewing from the facilities, the complaint alleged.