EPA head Scott Pruitt on Tuesday signed a new directive about who can serve as science advisers to the agency.

The Environmental Protection Agency announced on Tuesday afternoon sweeping changes to who can advise the agency on its research and regulatory priorities, opening the door to more industry participation.

Effective immediately, scientists who receive EPA funding cannot serve on the agency's three major advisory groups. Some Republican lawmakers have been pushing for similar changes to the agency's advisory boards for years.

"We want to ensure that there’s integrity in the process and that the scientists that are advising us are doing so without any type of appearance of conflict of interest," EPA head Scott Pruitt said at a press conference announcing the directive.

Pruitt used a story from the Book of Joshua to help explain the new policy.

On the journey to the promised land, "Joshua says to the people of Israel: choose this day whom you are going to serve," Pruitt said. "This is sort of like the Joshua principle — that as it relates to grants from this agency, you are going to have to choose either service on the committee to provide counsel to us in an independent fashion or chose the grant. But you can’t do both. That’s the fair and great thing to do."

A large coalition of science organizations, science advocates, environmentalists, and politicians lined up in fierce opposition to the policy changes, arguing the rules not only disqualify top environmental and health researchers from advising but also favor scientists paid for by EPA-regulated companies. They also have pointed out that EPA has strict rules in place for disclosing any conflicts of interest.