In response to several fatal accidents, the federal government has intensified its scrutiny of commercial driver’s licenses issued to immigrants in eight states.

Transportation Secretary Sean Duffy has issued warnings to California, Pennsylvania, Minnesota, and New York, threatening to cut off millions in federal funding following discoveries of licenses being valid beyond the expiration of an immigrant’s legal status. Quietly, the department also sent letters with similar warnings to Texas, South Dakota, Colorado, and Washington during the government shutdown, following brief mentions of these states in September.

Alarm over immigrant truck drivers spiked after an unauthorized driver executed an illegal U-turn in August in Florida, resulting in a crash that killed three people. This was compounded by another tragic incident in October in California, where a fiery crash, also involving an unauthorized truck driver, resulted in three fatalities.

In September, Duffy proposed stringent new regulations aimed at drastically reducing the eligibility of noncitizens for obtaining licenses to operate semis or buses. However, the implementation of these rules has been halted by a court decision.

Moreover, since the summer, the Trump administration has been vigorously enforcing existing English language requirements for truck drivers. By October, approximately 9,500 truckers nationwide had been taken off the road for failing to demonstrate English proficiency during traffic stops or inspections.

Here’s a summary of what has happened so far:

California

The Transportation Department focused first on California because the driver in the Florida crash got a license there. He also went to California after the crash and had to be extradited to face charges.

California fought back after Duffy threatened to pull $160 million from the state. Gov. Gavin Newsom sparred with Duffy in statements and social media posts defending the state’s practices by saying California officials had verified the immigration status of all these drivers through federal databases, as required.

But after that back-and-forth, California revoked 17,000 commercial driver’s licenses last month after confirming problems with them. That number has since grown to 21,000. So the Transportation Department hasn’t pulled that funding.

But Duffy did revoke a separate $40 million in federal funding because he said California is the only state not enforcing English language requirements for truckers.

Pennsylvania

The federal government might withhold nearly $75 million from Pennsylvania if it is not satisfied with the actions the state takes.

The Transportation Department said its audit found a couple of licenses out of 150 it reviewed were valid after the driver’s lawful presence in the country ended. In four other cases, the federal government said Pennsylvania gave no evidence it had required noncitizens to provide legitimate proof they were legally in the country at the time they got the license.

As it has done in all these states, the Transportation Department ordered Pennsylvania to stop issuing commercial driver’s licenses to immigrants until it completed a full review to ensure all the licenses it has issued remain valid and revoke any licenses that aren’t.

The federal government said that approximately 12,400 noncitizen drivers hold an unexpired commercial learner’s permit or commercial driver’s license issued by Pennsylvania.

Minnesota

Duffy threatened to withhold $30.4 million from Minnesota if that state doesn’t address shortcomings in its commercial driver’s license program and revoke any licenses that never should have been issued.

The Transportation Department found some licenses that were valid beyond a driver’s work permit and some where the state never verified a driver’s immigration status.

The head of Minnesota’s Department of Driver and Vehicle Services, Pong Xiong, said the state found a number of administrative issues in the 2,117 non-domiciled commercial licenses the state has issued and took action, including cancelling some licenses. Xiong said the federal audit largely just confirmed the issues Minnesota had already found and corrected.

The state planned to work with federal officials to resolve any remaining questions.

New York

Duffy highlighted concerns about the commercial licenses New York has issued to noncitizens Friday.

Federal investigators found that more than half of the 200 licenses they reviewed in New York were issued improperly with many of them defaulting to be valid for eight years regardless of when an immigrant’s work permit expires. And he said the state could not prove it had verified these drivers’ immigration status for the 32,000 active non-domiciled commercial licenses it has issued. Plus, investigators found some examples of New York issuing licenses even when applicants’ work authorizations were already expired.

“New York must act immediately to comprehensively audit its CDL program and revoke every single illegally issued licenses,” said Derek Barrs, administrator of the Federal Motor Carrier Safety Administration.

State DMV spokesperson Walter McClure defended the state’s practices and said New York has been following all the federal rules for this kind of commercial license.

Texas

Nearly half of the 123 licenses investigators reviewed in Texas were flawed, so the Transportation Department threatened to withhold $182 million if the state doesn’t reform its licensing programs and invalidate any flawed licenses.

A spokesperson for Texas Gov. Greg Abbott said in a statement that “public safety is the Governor’s top priority, and we must ensure that truckers can navigate Texas roadways safely and efficiently. To support this mission, Governor Abbott directed the Texas Department of Public Safety to strictly enforce English language proficiency requirements and to stop issuing intrastate commercial driver’s licenses to drivers who do not meet those standards.”

South Dakota

Investigators found three commercial licenses the state issued that were valid longer than they should have been. South Dakota also issues several licenses to Canadian citizens who aren’t eligible to get one.

One problematic practice investigators found as they reviewed 51 South Dakota licenses was that the state routinely issues temporary paper licenses that are valid for one year regardless of the immigration status of a driver.

South Dakota officials didn’t immediately respond Friday to the concerns. The state could lose $13.25 million.

Colorado

Roughly 22% of the 99 licenses that were reviewed in Colorado violated federal requirements. That raises questions about the 1,848 active non-domiciled commercial driver’s licenses in the state.

Investigators discovered a glitch in Colorado’s computer system that will revert to a license valid for four years when a worker has to do multiple searches in a federal immigration database. Unless the worker is vigilant, some of those extended licenses sneak through.

Eighteen Mexican citizens who weren’t eligible were also issued commercial licenses.

Jennifer Giambi, a spokesperson for the Colorado DMV, said the state is in the middle of auditing its licensing program to check for any additional problems, and that audit should be done by January. No new licenses are being issued in the program right now.

Washington

The state could lose $31.35 million if the Transportation Department isn’t satisfied with their response.

Investigators only found problems in about 10% of the 125 licenses they reviewed in Washington, but they were alarmed to learn that an internal state review discovered 685 immigrant drivers who were issued regular commercial licenses instead of the non-domiciled ones they should have received. The Transportation Department said that state officials often accepted the wrong documents in those cases.

Washington officials told the AP they couldn’t immediately respond Friday while the state is grappling with widespread flooding. But earlier this week, a state Department of Licensing spokesperson, Nathan Olson, said in an email to the Seattle Times that the errors had been addressed and Washington is working to improve its system and procedures.