Herman Cain is having a moment. Thanks to his economics-by-mnemonics plan and his unconventional, smoke-filled ads, Cain recently shot to the top tier of the GOP campaign. He became what Ryan Lizza called the fringe frontrunner.

But when you step to center stage, you realize just how glaring the spotlight can be. Cain’s campaign is reeling from revelations that two former employees at the National Restaurant Association accused Cain of “inappropriate behavior.” His inconsistent statements about the ordeal are only making matters worse.

The harassment story will dominate Cain’s coverage for some time to come, but there is another scandal lurking in the background that deserves attention as well.

Mark Block, Cain’s chief of staff, has been implicated in a host of campaign financing improprieties. And as researchers pore over financial documents, they have found substantial links between Cain, Block, and the Koch Brothers.

Koch Industries own oil refineries and 4,000 miles of pipeline and was named one of the top 10 air polluters in the nation in a 2010 UMass-Amherst report. The Kochs’ political donations are often aimed at promoting their Libertarian views, but they also directly benefit their own profit margins. They have donated millions of dollars to nonprofit groups that fight environmental regulation and seed doubt about climate science. A Greenpeace report called them a “kingpin of climate science denial.” And though green groups tend to paint ExxonMobil as the worst of the worst when it comes to lobbying against climate legislation, Koch outspent even them.

It’s no surprise that Cain would attract Koch money and dollars. He says he doesn’t believe in climate change, and he believes public health and environmental safeguards are “burdensome.” Those are appealing positions for dirty polluters like the Koch’s business interests.

But now we can connect the dots. Cain’s Chief of Staff Mark Block ran the Wisconsin chapter of Americans for Prosperity, a group cofounded by the Koch brothers to develop the Tea Party movement. Block met Cain through Americans for Prosperity and encouraged him to run for president. Block then launched spinoff groups from Americans for Prosperity, including Prosperity USA, which gave money and services to Cain’s campaign. It also paid for Block’s trip to meet with David Koch in Washington.

This doesn’t mean Cain was the Koch brothers’ top choice. They fund several candidates who back their anti-regulation, anti-clean energy, and anti-climate action agenda. They were major players in the midterm election and they will likely continue paying to keep their dirty talking points at the forefront of the presidential race.

That is their right, according to current campaign finance laws. But it is also voters’ right to know where the big money comes from and what kind of influence it buys. In the case of the Koch brothers, it seems to advance candidates who give polluters a free pass and disregard how this will damage the health of American families.