The Heartland Institute, the libertarian thinktank whose project to undermine science lessons for schoolchildren was exposed this week, faces new scrutiny of its finances – including its donors and tax status.

The Guardian has learned of a whistleblower complaint to the Internal Revenue Service about Heartland’s 501(c)(3) tax-exempt status…

The unauthorised release of internal documents indicated Heartland had received $14 million over several years from a single anonymous donor as well as tobacco and liquor companies and corporations pledged to social responsibility, including the General Motors Foundation.

The release of the donors’ list led a number of environmental organisations to demand GM, which gave $30,000, and Microsoft, which gave $59,908 in free software, to sever their ties with a thinktank that has a core mission of discrediting climate science…

Others are focusing on Heartland’s support from the tobacco industry as well as major health and pharmaceutical companies for a thinktank which has opposed smoking bans and healthcare reform.

John Mashey, a retired computer scientist and Silicon Valley executive, said he filed a complaint to the IRS this week that said Heartland’s public relations and lobbying efforts violated its non-profit status. Mashey said he sent off his audit, the product of three months’ research, just a few hours before the unauthorised release of the Heartland documents.

Mashey said in a telephone interview that the complaint looked at the activities of Heartland and two other organisations that have been prominent in misinforming the public about climate change, the Science and Environmental Policy Project, run by Fred Singer, and the Centre for the Study of Carbon Dioxide and Global Change, run by Craig Idso. Both men were funded by Heartland, with Idso receiving $11,600 per month and Singer $5,500 a month, according to the 2012 budget…

“I believe there was a massive abuse of 501c(3),” Mashey said. “My extensive study of these thinktanks showed numerous specific actions that violated the rules – such as that their work is supposed to be factually based. Such as there was a whole lot of behaviour that sure looked like lobbying and sending money to foreign organisations that are not charities.”

Mashey later published his audit of Heartland finances in Desmogblog, which was the first outlet to run the trove of Heartland documents.

Overdue. Creeps like this violate federal law on non-profit status all the time when they serve as a lobbying front for corporations with a vested interest in Heartland’s comments – whether that be climate, tobacco or fronting for pharmaceutical companies.