Transportation Secretary Sean Duffy said Wednesday he will withhold $40 million from California because it is the only state that is failing to enforce English language requirements for truckers.

An investigation launched after a deadly Florida crash involving a foreign truck driver who made an illegal U-turn on Aug. 12 found what Duffy called significant failures in the way California is enforcing rules that took effect in June after one of President Donald Trump's executive orders. California had issued the driver a commercial license, but these English rules predate the crash.

Truckers are supposed to be disqualified if they can't demonstrate English proficiency, and Duffy said the driver involved in the crash should not have been given a commercial license because of his immigration status. The crash has become increasingly political, with the governors of California and Florida criticizing each other and Duffy highlighting the administration's immigration concerns in interviews.

"California is the only state in the nation that refuses to ensure big rig drivers can read our road signs and communicate with law enforcement. This is a fundamental safety issue that impacts you and your family on America's road," Duffy said.

California defended its practices in a formal response to the Transportation Department last month, but federal officials weren't satisfied.

The office of California Gov. Gavin Newsom quickly pushed back after the announcement Wednesday. Diana Crofts-Pelayo, a spokesperson for the governor, said statistics show that California commercial truck drivers have a lower crash rate than the national average.

But Duffy said when he announced his concerns in August that California had conducted roughly 34,000 inspections that found at least one violation since the new language standards took effect. But only one inspection involved an English language rules violation that resulted in a driver being taken out of service. And 23 drivers with violations in other states were allowed to continue driving after inspections in California.

The Transportation Department said that to get this funding reinstated, California must adopt regulations to enforce the English rules and ensure that state inspectors are testing truck drivers' English skills during roadside inspections and pulling anyone that fails out of service.

In addition to this English language issue, Duffy has threatened to pull another $160 million from California because of the way the state issues commercial drivers licenses. Duffy significantly restricted who can qualify for those licenses last month.

Three people died when truck driver Harjinder Singh made an illegal U-turn on a highway about 50 miles (80 kilometers) north of West Palm Beach and a minivan slammed into his trailer, according to Florida's Highway Patrol. Singh and his passenger were not injured.

He is being held without bond after being charged with three state counts of vehicular homicide and immigration violations. His lawyer has previously declined to comment on the case.

The crash received intense scrutiny because of questions about Singh's immigration status and because investigators said he failed an English proficiency test afterward. Duffy and Florida officials blamed California as well as Washington state for issuing him a commercial driver's license.

But California officials said he had a valid work permit at the time. And New Mexico released video of a traffic stop that showed Singh communicating with an officer effectively after he was pulled over there in July.

Duffy, President Donald Trump and Florida Gov. Ron DeSantis have all be trading barbs with Newsom over the crash and whether Singh should have been driving a truck.

Newsom's office said California followed all the rules when it issued a license for Singh in July 2024, while the federal government confirmed at that time that he was in the country legally.

Duffy and Florida authorities have said Singh, who is from India, entered the country illegally from Mexico in 2018.