This semester, Divest Harvard and Democracy Matters teamed up to investigate Harvard’s fossil fuel investments. The Intergovernmental Panel on Climate Change estimates that around $100 billion dollars need to be divested from fossil fuel extraction each year for the next twenty years to meet climate goals. Yet Harvard refuses to draw down its fossil fuel investments and is even making new private equity investments in oil and gas exploration and extraction. This led us to wonder: Exactly what is Harvard investing in?

To investigate, we looked into Harvard’s Security and Exchange Commission filings, which are available to the public. Although these reveal only about 3% of Harvard investments, they provide a window into the fossil fuel companies Harvard invests in.

One area we focused on was fracking (short for “hydraulic fracturing”), a process in which high-pressure (and toxic) fluids are pumped underground to break apart rocks holding oil and gas. Recent peer-reviewed research has indicated that the process can contaminate groundwater used for drinking with toxic chemicals and can release large amounts of methane, a potent greenhouse gas, into the atmosphere.

So what do Harvard’s fracking investments look like? Since 2014, Harvard has invested in at least nineteen companies in the fracking sector, including production companies (Anadarko, Athlon Energy, Atlas Energy, Atlas Resource Partners, Concho Resources, EOG Resources, Hess Corp., Marathon Oil, Pioneer Natural Resources, Range Resources, Viper Energy Partners, and WPX Energy), equipment and operations companies (Baker Hughes, Cameron International Corp., and Dresser-Rand), and pipeline and export companies (Cheniere Energy, Energy Transfer Partners, Kinder Morgan, and Williams Companies, Inc.) Harvard’s disclosed investments in fracking peaked in 2014, when it reported that $346 million—or 30% of all reported investments—were devoted to these companies. For comparison, that’s about seventeen times the size of Harvard’s entire $20 million Climate Change Solutions Fund.

Many of these companies have less-than-responsible track records. Take Range Resources, in which Harvard invested about $2 million in 2014 and 2015. The company has been found responsible for over 200 legal violations in Pennsylvania alone. An investigation by the New York Times in 2011 found widespread evidence of poisoning of local residents by the company’s fracking chemicals. The company has a history of strong-arming communities in order to push for favorable drilling policies, and in litigation, the company has imposed lifelong gag orders on affected individuals, including on children, barring them from speaking about the fracking industry for the rest of their lives.

The company also makes a concerted effort to buy favor from politicians. It has its own Political Action Committee, the Range Resources Energy PAC, which gives money to politicians in Pennsylvania, where it operates. This mirrors a larger trend from the oil and gas industry of using political donations to influence policy.

Range Resources is not alone in its history of legal violations. A 2015 report by the Natural Resources Defense Council lists three other companies Harvard has invested in—Anadarko, Pioneer, and WPX—as top violators.

Harvard reports only about 3% of its investments to the SEC. If the rest of the endowment is weighted even remotely similarly to the portion made publicly available, then Harvard may have invested billions of dollars in fracking in the past two years (which would be hundreds of times greater than the size of Harvard’s Climate Change Solutions Fund). And this does not include Harvard’s other fossil fuel investments, like coal, non-fracked oil and gas, pipelines, and oilfield services.

For climate, as anything else, education is important. We know about the climate-related research Harvard supports through its facilities and staff. But it is also important to know about Harvard’s own role in polluting activities. Our investigation of Harvard’s investments in fossil fuels, including fracking, provides a small window into those activities. There are hundreds of millions of dollars in fossil fuels we can see—and potentially billions that remain hidden.

Benjamin A. Franta is a PhD Candidate in Applied Physics at the Harvard School of Engineering and Applied Sciences and a Research Fellow at the Belfer Center for Science and International Affairs at the Harvard Kennedy School of Government.