GenOn Mid-Atlantic, LLC v. Montgomery County, Maryland

The Fourth Circuit held that the federal Tax Injunction Act does not prevent the owner of a power plant from challenging a county excise tax on carbon dioxide emissions which is only levied on the plant. The court, overturning a district court decision which held that the county fee was a tax and the power plant was thus barred from challenging it in federal court by the Tax Injunction Act, held that the fee was actually a “punitive regulatory matter” and that single entities subject to such punitive financial strikes should be able to challenge them in federal court.