Top advisers to the billionaire environmentalist Tom Steyer helped run a green group, financed in part by Steyer himself, that is at the center of a corruption scandal that could force the Democratic governor of Oregon to resign.

An executive at one of Steyer’s nonprofit groups and a political vendor who has received hundreds of thousands of dollars from the hedge fund manager’s political operations helped run the group, which is accused of influencing state energy policy through undisclosed payments to Oregon’s first lady.

The controversy centers on Gov. John Kitzhaber’s fiancée, Cylvia Hayes. She was paid $118,000 by the Clean Economy Development Center (CEDC) to advocate for environmentalist policies in Oregon.

Hayes never disclosed those payments, despite acting as an informal adviser to the governor as he pushed a low-carbon fuel standard for the state.

Dan Carol, then a strategic adviser to CEDC, helped Hayes land the position. He was given a $165,000-per-year job in the Kitzhaber administration.

Kitzhaber is expected to resign today under intense scrutiny over the scandal. The scandal could extend beyond Oregon given Steyer's involvement. Steyer has donated millions to a group that helped finance Hayes’ position, which could ensnare one of the Democratic Party’s most prominent fundraisers in the scandal.

Hayes was reportedly a fellow at the CEDC in 2011 and 2012, but as of late as August of last year, she was still listed on a since-deleted page of its website.

Also listed on that page was Kate Gordon, a member of the CEDC’s board. Gordon leads the energy and climate division of Next Generation, an environmental nonprofit group founded by Steyer.

Another director of the group, according to the website, was Mike Casey. Casey runs a media and public relations firm called Tigercomm that does polling and advertising work for Steyer’s Super PAC, NextGen Climate Action.

Casey reportedly wrote NextGen’s communications strategy for its involvement in elections in Massachusetts and Virginia in 2013. NextGen and another Steyer group, the CE Action Committee, paid Tigercomm $387,000 that year.

Casey denied having served on the group's board, though he admitted to doing communications work for CEDC through Tigercomm. When asked why the website listed him as a member of the board, Casey said, "Best I can tell, there’s a cached page from June 2013 saying I’m a board member. I never was, as CEDC has confirmed to you. Not sure what else to tell you."

CEDC executive director Jeff King said in an email that Casey and Gordon were never board members, "but were erroneously listed as such at one point." He would not say who listed them, why, when, or what their roles with the organization were. The IRS revoked CEDC's tax exempt status in August after it failed to file annual reports for three straight years.

Former CEDC board members, according to the website, include Andy Stern, the former president of the Service Employees International Union. His former assistant, Josie Mooney, is a strategic adviser to NextGen.

David Chen, a former member of CEDC’s advisory board, has hosted Steyer at events held by his investment firm, Equilibrium Capital. Steyer also sits on the board of the Center for American Progress, whose senior fellow in energy and environmental policy, Bracken Hendricks, was listed as a CEDC adviser.

As his team and others to which he has ties helped run CEDC, Steyer steered funds to the group financing Hayes’ fellowship.

Internal Revenue Servicing filings show that the Energy Foundation provided $75,000 to CEDC in 2011 and 2012. The foundation said the funds would help "build support for dean energy policy in the Northwest." It told the Oregonian that it was supporting the fellowship specifically.

Steyer’s TomKat Charitable Trust has donated more than $3 million to the Energy Foundation.

Steyer is arguably the nation’s most prominent environmentalist financier, but other high-dollar donors to similar groups also bankrolled CEDC generally and Hayes’ fellowship specifically.

The Rockefeller Brothers Fund, a foundation that provides significant financial support for U.S. green groups, granted $25,000 to CEDC in 2012 specifically earmarked for its Clean Economy Acceleration Fellowship Program.

That came after a $100,000 grant to CEDC the year before, itemized as "general support."

Jessica Bailey, until 2012 a program officer for sustainable development at RBF, also served as a strategic adviser to CEDC.

A former CEDC director, Aimee Christensen, also worked with RBF through her consulting firm, Christensen Global Strategies. According to its website, another of her clients was the Sea Change Foundation, which has quietly poured hundreds of millions of dollars into U.S. environmentalist groups.

Among those groups is the Energy Foundation, which has received nearly $65 million from Sea Change.

Updated: Comment from Jeff King and Mike Casey added above.