Environmental groups challenging permits for a natural gas pipeline and export facility in south Texas lost a legal fight at a federal appeals court Thursday.

A panel of the 5th U.S. Circuit Court of Appeals in New Orleans said the U.S. Army Corps of Engineers approved the “least environmentally damaging” alternative submitted during the permitting process.

The permit was granted for the project of Rio Grande LNG and Rio Bravo Pipeline Company. The rejected court challenge was filed by the Shrimpers and Fishermen of the RGV, the Sierra Club and a group called Save RGV from LNG. The groups announced their challenge in 2021, saying the project posed an environmental threat to low-income communities, shrimpers and fishers in the Rio Grande Valley region.

According to Thursday’s opinion, the groups argued that the permit violated the Clean Water Act. They challenged the Corps’ finding that the project’s disruption of environmentally vulnerable wetlands would be temporary and would not require mitigating action by the companies.

The 5th Circuit panel said the Corps considered studies showing that the area’s vegetation would return within a year of the project’s completion.