Washington • The White House on Thursday will introduce the first major changes to the nation’s bench mark environmental protection law in more than three decades, moving to ease approval of pipelines and other major energy and infrastructure projects without detailed environmental review.

Many of the changes to the 50-year-old National Environmental Policy Act, a landmark measure that touches nearly every significant construction project in the country, have been long sought by the oil and gas industry, whose members applauded the move and called it long overdue.

White House officials Thursday morning declined to comment on the proposed regulations, which will be formally released later in the day. One person familiar with the announcement said the administration would highlight a replacement of the Herbert C. Bonner Bridge in North Carolina, which took more than 20 years because of federal reviews. Administration officials will argue that the changes will help projects like that one move faster.

Under the law, major federal projects like bridges, highways, pipelines or power plants that will have a significant impact on the environment require a review, or environmental impact statement, outlining potential consequences. The proposed new rules, which guide the way the law is implemented, will narrow the range of projects that demand such a review. It will do that by creating a new category of “non-major” federal actions that can move forward without any assessment, according to two government officials familiar with the regulation.

In some cases the federal government merely funds studies for small infrastructure projects, which triggers a required environmental review.

But the proposed regulation does not set a dollar threshold for what constitutes a large federal footprint, which one official said could also allow major mining, drilling and other projects to avoid environmental assessments. That lack of definition is highly likely to prompt lawsuits from environmental organizations.

“Our country is at a pivotal time for American energy,” said Anne Bradbury, chief executive of the American Exploration & Production Council, which represents independent operators.

She praised the administration for clarifying the regulations and creating what she described as a more-efficient process that “removes bureaucratic barriers that were stifling construction of key infrastructure projects.”

Environmental groups said the revisions would threaten species and lead to more greenhouse gases in the atmosphere. The proposed regulations also will relieve federal agencies of having to take climate change into account in environmental reviews.

The proposal will not mention the words “climate change” but will say that agencies no longer must consider the “cumulative” consequences of new infrastructure. Courts have interpreted that requirement as a mandate to study the effects of allowing more planet-warming greenhouse gas emissions into the atmosphere. It also has meant understanding the impacts of rising sea levels and other results of climate change on a given project.

That means agencies will not have to examine whether a pipeline, mine or other fossil fuel project would worsen climate change. It also means there will not be any requirement to understand how or whether a road or bridge in a coastal area would be threatened by sea-level rise.

Richard L. Revesz, a professor of environmental law at New York University, said he did not believe the changes would hold up in court. He noted that the Environmental Policy Act requires that all the environmental consequences of a project be taken into account, and that core requirement cannot be changed by fiat.

“A regulation can’t change the requirements of a statute as interpreted by the courts,” Revesz said. In fact, he argued, it is more likely that federal agencies will be sued for inadequate reviews, “thereby leading to far longer delays than if they had done a proper analysis in the first place.”