A federal judge in Baton Rouge has halted construction of the Bayou Bridge crude oil pipeline planned through the heart of the Atchafalaya Basin, granting the request of environmental groups opposed to the project.

Saying she will later explain her ruling, U.S. District Court Judge Shelly Dick issued an order Friday prohibiting the companies building the pipeline from continuing construction. Work on the pipeline had begun in January, after final permits were approved. 

In the order issuing a preliminary injunction, Dick wrote that she was enjoining further work on the pipeline "in order to prevent further irreparable harm until this matter can be tried on the merits."

In this case, Earthjustice brought a federal suit on Jan. 11 against the U.S. Army Corps of Engineers on behalf of the Atchafalaya Basinkeeper, the Louisiana Crawfish Producers Association-West, the Waterkeeper Alliance and the Sierra Club. They allege the Corps acted "arbitrarily and capriciously" when it issued a key permit for the pipeline.

Those groups welcomed Dick's decision Friday.

“The court’s ruling recognizes the serious threat this pipeline poses to the Atchafalaya Basin, one of our country’s ecological and cultural crown jewels,” Jan Hasselman, an Earthjustice attorney, said in a statement. “For now, at least, the Atchafalaya is safe from this company’s incompetence and greed.”

A spokeswoman for Energy Transfer Partners, a joint owner of the pipeline project, declined comment. "The Judge did not issue any opinion explaining her order. Until such time as that is issued, and we can review, we will have no further comment," said Alexis Daniel in an email. 

In a statement late last month, the company noted that Eunice-based Sunland Construction had been hired to build about one-third of pipeline's length, from St. Martin to St. James parishes. The line will extend all the way to Lake Charles and link up with an operating section of line that goes to Nederland, Texas.  

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The company has touted the pipeline's employment and tax revenue benefits and its ability to improve the efficiency of oil transport from the nation's mid-section and parts north to oil terminals and refineries along the Mississippi River and elsewhere on the Gulf Coast.

The full 163-mile project will employ approximately 2,500 construction workers, Energy Transfer Partners has said in earlier statements. Sunland was expected to hire additional construction workers to build its segment of the project.

But Dick's ruling came about two weeks after a day and a half of  testimony earlier this month in which environmental groups argued the Corps didn't perform its due diligence when the project was allowed to move forward. They argued the Corps failed to require pipeline builders to take meaningful steps to offset the environmental impact of building the pipeline and did not thoroughly consider the potential destruction of a spill, especially in the Atchafalaya Basin.

In a statement from the Basinkeepers, the groups noted that testimony included claims that the pipelines would degrade crawfishing grounds and that "ancient cypress and tupelo trees slated to be turned into mulch while the pipeline right-of-way is being cleared would never return, including evidence that these old-growth trees are the Noah's Ark of the swamp — providing habitat for migratory birds, bears, bats and numerous other wildlife."

Lawyers for the pipeline companies and Corps told Dick the conservation groups misrepresented the pipeline review, which they said looked exhaustively at potential spills and considered the best way to offset negative impacts on the Atchafalaya Basin. Work that compensates for construction that affects sensitive wetlands is also known as wetlands mitigation.

They also asked the judge to consider the costs to both the company and workers building the pipeline should construction be halted.

Ricky Boyett, spokesman for the Corps, said Friday evening that the agency does not comment on pending litigation.

Follow David J. Mitchell on Twitter, @NewsieDave.