A major labor union has launched an ad blitz ripping Dem Gov. Kathy Hochul as so “radioactive” and “toxic” that midterm candidates from her own party want nothing to do with her.

The Transport Workers Union of America, whose local members include roughly 40,000 city subway and bus workers toiling under an MTA contract that lapsed in May, began airing the scathing spots Friday, a day before early voting opened.

“Governor Kathy Hochul is so radioactive, even Democratic candidates are running away from her,” the ad kicks off, referring to the state’s top Democrat who effectively controls the MTA through appointments.

“They’re increasingly recognizing that the governor is a disaster for working New Yorkers and a major drag on their own political campaigns.”

The ads reference Dem Long Island Rep. Tom Suozzi bailing on a campaign event with Hochul and Democratic Hudson Valley congressional hopeful Cait Conley being caught on video agreeing with her Republican opponent that the incumbent governor has “got to go” — both instances that were first reported by The Post.

Transit union honcho John Samuelsen told The Post that in addition to the $60,000 spent on the new ads, the union’s super PAC is plunking down an additional $120,000 on more TV ads playing across the state and sent out “hundreds of thousands” of mailers to trade-union families in New York, too.

“If she wasn’t perpetually attacking trade unions, she wouldn’t be so toxic and maybe other Democrats would be more willing to stand with her,” he said.

State campaign finance records show that the Transport Workers Union Voice has spent more than $450,000 on television advertisements since they registered with the state in July. 

Samuelsen has blasted the governor as anti-labor since she vetoed a bill that would have required a conductor on all subway trains along with a train operator. 

Hochul said in her veto message that the bill would “cost as much as $10 million annually, reducing service and limiting the MTA’s ability to benefit in modern rolling stock [new trains] and signals.”

GOP gubernatorial candidate Bruce Blakeman criticized the veto, saying the decision “put riders and transit workers at risk” and stood with the union.

Hochul and the transit workers union didn’t always butt heads.

The union and Local 100, which endorsed her in 2022, dumped more than $175,000 into her campaign accounts between 2018 and 2024, state records show.

A rep for Hochul’s campaign told The Post on Sunday, “Governor Hochul comes from a union family and has always stood up for workers, created good-paying union jobs, and fought for better pay and working conditions – she’s proud to have earned the support of the more than thirty New York unions who can’t trust ‘100% MAGA’ Blakeman to protect their rights, safeguard their healthcare, or bring down their costs.”