Mr. Jones noted that whatever role the government might have had in wetlands loss, Washington had spent billions on repairing and strengthening hurricane defenses since the system built by the Corps of Engineers failed after Hurricane Katrina in 2005. By taking the companies to court, he said, “we want them to come and pay their fair share.”

A spokeswoman for BP said the company would have no comment. A spokesman for Exxon Mobil said the company had no comment at this time.

The role of the industry is well documented in scientific studies and official reports. In calling for remediation efforts, a 2012 report by the state’s Coastal Protection and Restoration Authority stated, “Dredging canals for oil and gas exploration and pipelines provided our nation with critical energy supplies, but these activities also took a toll on the landscape, weakening marshes and allowing salt water to spread higher into coastal basins.”

The suit argues that the environmental buffer serves as an essential protection against storms by softening the blow of any incoming hurricane before it gets to the line of levees, flood walls, and gates and pumps maintained and operated by the board. Losing the “natural first line of defense against flooding” means that the levee system is “left bare and ill-suited to safeguard south Louisiana,” the lawsuit says.

The “unnatural threat” caused by exploration, it states, “imperils the region’s ecology and its people’s way of life — in short, its very existence.”

The lawsuit relies on well-established legal theories of negligence and nuisance, as well as elements of law more particular to the Louisiana Civil Code, including “servitude of drain,” which relates to changing patterns of water flow and drainage across the Bayou State. Even though the industry has been producing oil and gas for 100 years, because the damage is continuing to occur, the board argues, the statute of limitations should not apply.

Walter Olson, a Cato Institute expert on litigation who often expresses skepticism about civil litigation, said that he could not comment extensively without seeing the filing, but that “it sounds like the sort of thing you couldn’t dismiss out of hand.” He said some environmental lawsuits, like one against power companies over the effects of climate change on sea-level rise and its effect on the Alaskan town of Kivalina, incorporate creative legal arguments that may not stand up in court. “It’s not Kivalina,” he said, if the plaintiffs can point to specific people or entities causing specific damage. He added that proving causation in court, however, “can be a big headache.”

No other state agencies have joined the lawsuit, and Mr. Barry said that during preparation of the suit, his board had not discussed the case with other levee boards. The politically powerful oil and gas industries might bring pressure to bear on others who might be inclined to join, Mr. Jones said, but now that the case has been filed, “it really raises the question that’s going to be asked at a whole lot of boards across southern Louisiana: Can we really afford not to do this?”