Billionaire environmentalist Tom Steyer is pushing an ad campaign targeting former ExxonMobil CEO Rex Tillerson, Donald Trump’s pick for Secretary of State.

The ad, launched by Steyer’s NextGen Climate non-profit group, claims that as CEO of ExxonMobil, Tillerson put his company’s interests first and did business with Russia.

But Steyer, a former hedge fund manager, has his own record of doing business with the Russians.

In 2010, Steyer’s hedge fund Farallon Capital Management profited from a sale of its stake in a Russian oil firm to a investment firm owned by Russian billionaire Gennady Timchenko, according to the Free Beacon.

Timchenko was later targeted by Treasury Department sanctions in 2014, due to his relationship with Vladimir Putin.

Steyer, a committed supporter of environmental causes and Democrats, endorsed Hillary Clinton in June 2016, and hosted a fundraiser for her in 2015.

“Tell your Senators to reject Rex Tillerson and protect American interests, not corporate interests,” the anti-Tillerson ad concludes.

Steyer spent more than $75 million in in the 2016 election, as his NextGen Climate action group spent millions to combat Trump with ads including this one:

Trump’s transition team should expect environmental groups to unite against Tillerson’s nomination, due to his former position as head of ExxonMobil.