The Trump administration is working to cement new standards weakening enforcement of the century-old Migratory Bird Treaty Act.

Interior Department officials said Thursday that they will propose regulations clarifying that individuals and industrial operators, such as oil, gas and wind companies, will not be penalized if they accidentally kill birds — even on a massive scale.

U.S. Fish and Wildlife Service Director Aurelia Skipwith said the new regulatory language is needed so that private industries “can operate without the fear and uncertainty that the unintentional consequences of their actions may be prosecutedwhen birds are killed. Officials said they will rely on companies to voluntarily protect birds.

Skipwith noted that her agency’s mission centered on protecting the nation’s wildlife and plant species.

“Migratory bird conservation is an integral part of that mission, and we are fully committed to it,” she said, adding that the administration also wants to reduce regulatory obstacles.

Since guidelines under the administration’s interpretation of the law were issued in April 2018, hundreds of ducks, geese, herons and migrating birds have perished in oil pits, on utility lines and in other operations without penalty, according to documents compiled by conservation groups.

Birds, including hawks, owls and songbirds, are drawn to oil skim pits that resemble ponds from the air. They often swoop in to prey on bats, reptiles, insects and small game that are also attracted and fall into the pits, and struggle in the sticky oil. Oil pits alone are estimated to kill between 500,000 and 1 million birds each year, according to a 2010 report by the environmental management division of Fish and Wildlife.

Reid Porter, a spokesman for the American Petroleum Institute, said in an email that oil and gas companies routinely take precautions to protect birds and other wildlife near their operations. He noted that federal data shows other factors — including habitat loss, collisions with building glass, communication towers and wind and solar projects, and cats — pose a greater threat to birds than oil pits.

In the wake of the administration’s more lax enforcement of environmental protections, two major reports have flagged the perils facing wildlife. In May, a U.N. report found that 1 million plant and animal species are on the verge of extinction as a result of human activity. Four months later, a report by top ornithologists and government agencies found that nearly 3 billion birds across hundreds of species have been lost in North America. Both reports referred to their findings as a biodiversity crisis.

At least seven attorneys general and several conservation organizations challenged the administration’s opinion on the Migratory Bird Treaty Act in federal court.

No one knows how many birds were saved before the administration watered down the law, said Sarah Greenberger, a senior vice president for conservation at the National Audubon Society, but based on outreach the Fish and Wildlife Service undertook with the oil and gas industry under the stronger version of the Migratory Bird Treaty Act, the agency was able to downgrade the number of birds killed in oil pits by 50 percent.

The Fish and Wildlife Service has curtailed its enforcement of the law in the wake of the Dec. 22, 2017, legal opinion, according to documents released under the Freedom of Information Act. Agency officials have declined to pursue cases against companies whose actions have had lethal consequences for birds across the country.

Just over a month after the legal opinion was published, for example, a U.S. Coast Guard official notified employees from Interior, Fish and Wildlife, and the National Oceanic and Atmospheric Administration on Jan. 31, 2018, that the Coast Guard had identified the tugboat whose oil spill in Great Harbor, Mass., killed more than two dozen birds.

After one Fish and Wildlife Service employee asked whether it was “time to get on a conference call” with Interior Department lawyers, the agency’s resident agent in charge for New England made it clear that it would not be necessary.

The agency’s police are following a new legal opinion, the agent wrote. “As this spill involves the incidental take of birds protected by the Migratory Bird Treaty Act, there is currently no enforcement action planned," the agent said.

Before Interior’s recent change, industries recognized that they had an obligation to take basic steps to protect birds as part of the global treaty. “Now the Fish and Wildlife Service is saying you don’t have to do that anymore. You can imagine the ripple effect across this country as companies abandon those practices and the long-standing impact that will have,” Greenberger said. “Historically the Migratory Bird Treaty Act has been one of the government’s most powerful and most effective tools.”

The proposed regulations are expected to be published Monday, followed by a 45-day period for public comment and then final language.

Under the Trump administration’s proposed regulations, companies at the center of disasters similar to the 1989 Exxon Valdez oil spill in Alaska, which killed an estimated 250,000 birds, and the 2010 Deepwater Horizon debacle, estimated to have killed more than 1 million birds, would not be penalized. After an oil spill, Interior would pursue penalties under the Natural Resources Damage Assessment program that is not specific to birds.

“It may not sound like big news … but it will have real effects on how agencies and companies will respond to this policy now,” Bob Dreher, a vice president for conservation at Defenders of Wildlife, said. “We will fight this new regulation on the same basis we will fight the solicitor’s opinion.”