The Trump administration is proposing a dramatic overhaul of the once-a-decade U.S. Census head count that could leave out millions of immigrants based on status and key racial and ethnic data, jeopardizing the allocation of resources and the country’s voting map.

The potential changes, announced Wednesday, would exclude undocumented immigrants, asylum seekers and anyone without permanent status. Certain demographic questions from the traditional questionnaire would also be eliminated.

It echoes Trump’s previous idea to add a citizenship question to the 2030 census.

The U.S. Census Bureau, in a post on the Federal Register website, argued “illegal aliens (among others) should not be included in the apportionment count, as they are not true inhabitants, members of the body politic, or persons with a ‘usual residence’ in the United States due to their lack of a sufficient tie and allegiance to the United States.”

The census also “should be colorblind and should not be distorted in any way by questions about immaterial personal characteristics, such as race,” the agency said. It also is considering nixing questions related to people who identify as part of the LGBTQ+ community.

These changes would harm the quality of the data, said Beth Jarosz, a data researcher and vice president of the Association of Public Data Users. She called the proposals “unprecedented.”

“Not counting all of the people who reside here is actually where the real threat is,” Jarosz said. “If you think about all of the ways that census data are used.”