In April 2018, a pipeline belonging to Texas-based petroleum company Andeavor ruptured near the small town of Buhl, Idaho, spilling about 7,000 gallons of diesel fuel across an area the size of five football fields, much of it ending up in a small creek and a pond used for livestock.

During the cleanup, workers discovered dead birds, internal U.S. Fish and Wildlife Service communications show. But no one appears to have looked into why the birds died, much less pursued action against anyone.

Its the kind of incident that the federal agency charged with protecting wildlife would historically have investigated, because killing many species of migratory birds either on purpose or unintentionally violates the 1918 Migratory Bird Treaty Act (MBTA). But months earlier, in December 2017, Daniel Jojani, the top lawyer at the Department of the Interior and a longtime former adviser to the fossil fuel moguls Charles and David Koch, issued a highly controversial legal opinion that allowed all unintentional migratory bird deaths, including those caused by oil and gas operations, chemical spills, power lines and wind turbines. As long as the birds die when a company or individual means to do something else, it isnt an issue, according to the opinion.

The move broke from decades of legal precedent, and the Trump administration has since introduced a rule to codify that change and permanently slash protections for hundreds of species of migratory birds.

Its an absurd, incorrect and illegal interpretation of the law, made even more outrageous by the fact that it comes amid a global biodiversity crisis that has pushed up to 1 million species to the brink of extinction , said Erik Schneider, a policy analyst at Audubon, one of several wildlife organizations challenging Trumps controversial policy in court.

And it has led the Trump administration to largely abandon investigating migratory bird deaths even in cases in which officials are unsure if the killings are unintentional, according to a batch of documents that American Bird Conservancy and other environmental groups obtained through public records requests and that were shared with HuffPost.