On March 2, his first full day in office, Trump Interior Secretary Ryan Zinke reversed an action taken by the Obama administration to phase out the use of lead ammunition and fishing tackle on national wildlife refuges by 2022.

Zinke said hunters were being discouraged from experiencing national outdoors sites and that his move was to “expand access for outdoor enthusiasts and also make sure the community’s voice is heard.”

Oregon has 18 national wildlife refuges and all 18 allow hunting. Lead is a neurotoxin; lead ammunition has been shown to be a significant source of toxic exposure in people who ingest wild game. Eight states already recommend pregnant women and children not consume venison killed with lead ammunition.

Environmentalists, who had been cheered by the Obama action, say spent lead casings poison thousands of birds and animals and that lead tackle contaminates waterways. Mary Coolidge, a specialist in lead poisoning with Portland Audubon notes that “even at sublethal levels, lead toxicity can reduce fitness in birds, impairing their ability to successfully hunt, forage, mate [and] escape predation.”

The risk is high for scavengers such as eagles, hawks, grizzly bears or others eat the scraps left by hunters. When a lead rifle bullet traveling at almost three times the speed of sound strikes animal tissue, says the National Park Service, it expands immediately and loses hundreds of tiny pieces as it continues its journey. Hunters trim away organs and other bloodshot areas filled with these pieces and leave them behind where even a small amount of lead can kill or sicken predators.

Non-lead bullets are sold in Oregon, but generally cost more and are somewhat less available than conventional lead ones.

Zinke’s decision to overturn the Obama ban “rolled us back to the status quo in which we continue to ignore this as a lead exposure pathway, which puts both humans and wildlife at risk,” says Coolidge. “It’s also but one example of the many ways that the current administration is systematically dismantling environmental protections, which is perilous for both humans and wildlife.”

According to the National Parks Service, more than 500 studies since 1898 have documented that 134 species of wildlife are threatened by lead in ammunition.

“There is a basic tenet of ethical hunting that says that a bullet should only kill once, and it should one kill the intended target,” says Coolidge. “Hopefully, as hunters learn more about the unintended consequences of hunting with lead ammunition, they will be moved to make decisions that uphold the spirit of ethical hunting and sportsmanship.”

Some observers, sportsmen and gun-rights advocates were cynical about the Obama action, which occurred on January 19, only one day before the Trump inauguration.