LANSING – Millions in new television advertisements are set to hit the airwaves, again slamming Republican U.S. Senate candidate Terri Land on environmental issues.

This time, it is the NextGen Climate organization, founded by liberal billionaire Tom Steyer, tying Ms. Land to the billionaire conservative brothers Charles and David Koch – the de rigueur punching bag this election cycle for Democrats and liberal causes. Republicans have tried to flip that script and make Steyer into their bogeyman, although not nearly to the extent the Democrats have with the Kochs, whom they have pilloried nationally.

The ad highlights the most polluted part of the state in southwest Detroit and emphasizes the controversy that erupted in 2013 over piles of petroleum coke, a tar sands oil byproduct, stored in open air adjacent to the shoreline of the Detroit River by a company that is a subsidiary of a Koch-led firm. That company later moved the piles to Ohio.

Americans for Prosperity and Freedom Partners, groups funded by the Kochs, paid for $5.1 million in advertising criticizing Land’s Democratic opponent, U.S. Rep. Gary Peters, during the winter and spring. The ads stopped in June.

“Now they’ve dumped millions to elect Terri Lynn Land so she’ll let them keep polluting,” the narrator says in the ad.

A smaller buy of $400,000 from the League of Conservation Voters also hits on the Koch theme and attributes the recent metro Detroit flood and Toledo water crisis to climate change. The ad seizes on a statement Land’s campaign gave earlier in the year in which her spokesperson said Land disagrees with Peters on the extent to which humans are responsible for climate change.

Chris Lehane, an adviser to Steyer, said the group has found through its polling that the Kochs have a highly negative image in Michigan. NextGen officials said it is pairing a grassroots effort with the ad designed to mobilize minority and college student voters, especially those who tend not to vote as frequently.

Lehane said it is clear the criticism of the Kochs is working in Michigan because their organizations have stopped airing ads.

“You can gauge an awful lot about how the other side is reacting and handling a situation,” he said.

Republicans have sought to blunt the ads’ effect by hammering at Mr. Steyer, asserting Mr. Peters has only opposed the construction of the Keystone XL oil pipeline to appease him. Mr. Peters has said he cannot support the pipeline without greater assurances on dealing with environmental issues like petroleum coke.

“With Congressman Gary Peters crashing in the polls, national Democrats are afraid, desperate and have resorted to calling in their California billionaire and radical environmentalist Tom Steyer to spend millions to rescue Gary Peters, who can’t shake his long record of killing Michigan jobs,” Land spokesperson Heather Swift said in a statement. “One thing is clear: Gary Peters will not put Michigan first because he puts the California billionaire Tom Steyer first.”

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