North Carolina could lose nearly $50 million in federal funding if the state does not revoke commercial driver’s licenses issued to immigrants who are not qualified to hold them, the U.S. Transportation Department said Thursday.

The department said an audit uncovered problems with more than half of the 50 commercial driver’s licenses that the Federal Motor Carrier Safety Administration reviewed in North Carolina. It said the problems prompted a threat to withhold funding unless the state cleans up its licensing program, and it cited records showing 924 of these kind of licenses remain unexpired in the state.

Transportation Secretary Sean Duffy launched a nationwide review last year aimed at ensuring only qualified drivers hold licenses to operate semitrailer trucks or buses, the department said. It said North Carolina is the ninth state targeted since the review began.

The crackdown gained national attention after a crash in Florida in August that killed three people, the Transportation Department said. It said the crash involved a truck driver who was not authorized to be in the U.S. and followed an illegal U-turn.

“North Carolina’s failure to follow the rules isn’t just shameful — it’s dangerous,” Duffy said.

In response, North Carolina DMV spokesman Marty Homan said the state is working to address the concerns and remains “committed to upholding safety and integrity in our licensing processes.”

Duffy has previously taken similar actions against other states. He has pulled nearly $200 million from California over concerns about its licensing practices and its decision to delay revocations of more than 17,000 invalid licenses, and he said California is not enforcing English proficiency requirements for truckers.

Duffy also said he previously threatened to withhold millions of dollars from Pennsylvania, Minnesota, New York, Texas, South Dakota, Colorado and Washington after audits found significant problems under the existing rules. The department said those audits included findings that some commercial licenses were valid long after an immigrant truck driver’s work permit expired.

Separately, Tennessee announced Thursday that it launched its own review of commercial driver’s licenses and will be notifying about 8,800 of the state’s 150,000 commercial driver’s license holders that they need to provide proof of citizenship or a valid visa if they want to keep their licenses. Russell Shoup, assistant commissioner of Tennessee’s Driver Services Division, said the state is working to make sure all the licenses it has issued meet current state and federal standards.

The federal changes have drawn praise from trucking groups. The industry said that too often unqualified drivers who shouldn’t have licenses or cannot speak English have been allowed to get behind the wheel of an 80,000-pound truck, and it also applauded the department’s moves to pursue questionable commercial driver’s license schools.

Immigrant groups, however, said the spotlight is turning toward some drivers unfairly. The focus has included Sikh truckers, the report said, because the driver in the Florida crash and another fatal crash involving a driver in California in October were both Sikhs. The Sikh Coalition and the San Francisco-based Asian Law Caucus filed a class-action lawsuit against California over the state’s plan to revoke thousands of licenses.

The department also said the review involves noncitizen licensing rules. It said immigrants make up about 20% of all truck drivers, while the non-domiciled licenses immigrants can receive represent about 5% of all commercial driver’s licenses, or about 200,000 drivers. The Transportation Department also proposed restrictions that would severely limit which noncitizens could get a license, but a court put the new rules on hold.