As U.S. Senators grilled federal appeals court Judge Neil Gorsuch, President Donald Trump’s pick for the Supreme Court, Sen. Dick Durbin, D-Ill., hit up Gorsuch on a case that stems from an incident in Illinois.

It’s been dubbed the case of the frozen trucker, and it’s been dogging Gorsuch since before his confirmation hearing began this week.

TransAm Trucking driver Alphonse Maddin stopped on a wintry night after his trailer’s brakes froze along Interstate 88 in Illinois. His torso went numb after waiting three hours in an unheated cabin for roadside assistance. A boss ordered him to not abandon the cargo. But Maddin, fearing for his health, unhitched the trailer and drove off. TransAm, a Kansas company, promptly fired him for disobeying an order.

In a dissent last year, Gorsuch said the Surface Transportation Assistance Act, which bars companies from firing a driver who “refuses to operate” an unsafe truck, didn’t apply to Maddin.

Why? Because, Gorsuch wrote, Maddin was operating the truck by driving off, not refusing to operate it. “There’s simply no law anyone has pointed us to giving employees the right to operate their vehicles in ways their employers forbid,” Gorsuch said. If one’s needed, he added, Congress should create it.

Writing for the majority, Judge Michael Murphy conceded some imprecise language. But he said the law could easily be seen as applying to drivers, such as Maddin, who are at risk by staying put. Murphy also directly challenged Gorsuch’s narrow, literal meaning of “operate.”

“The dissent believes Congress’ intent can be easily determined by simply choosing a favorite dictionary definition of the word,” Murphy wrote. But he added there was no doubt the law’s purpose was to keep drivers safe, so it was reasonable to find “a refusal to operate” encompassed a refusal to sit in a freezing truck.

Gorsuch’s judicial history, to some, suggests he isn’t employee friendly — and Democrats have seized on that in aiming to discredit him in advance of his confirmation vote.

Maddin, the “frozen trucker,” appeared with Democratic senators last week, the Washington Post reported.

“Seven different judges heard my case — one of those judges found against me,” Maddin said. “That judge was Neil Gorsuch.”

Senate Minority Leader Charles E. Schumer (D-N.Y.) said cases such as Maddin’s show Gorsuch “prefers CEOs over truck drivers, executives over employers, and corporations over consumers,” the Post also reported.

Gorsuch has sided with employers 21 out of 23 times in disputes over the U.S. pensions and benefits law, the Employee Retirement Income Security Act, or ERISA, according to an Associated Press analysis.