The Pennsylvania Environmental Defense Foundation is a left-of-center special-interest law firm. The Foundation files lawsuits against companies who produce pollutants and the state of Pennsylvania in order to demand more environmental regulations and restrictions.
The Foundation’s biggest victory was a lawsuit against the state of Pennsylvania that sought to ban oil and gas drilling on state-owned properties. The Pennsylvania Supreme Court ruled in 2017 that refusing to ban oil and gas drilling on state-owned properties violated the Pennsylvania state constitution, arguing that the state’s natural resources are held in public trust for all of the people of the Pennsylvania and that the state cannot act as a proprietor of those resources. 
The Foundation’s president has called for an end to all new oil and gas drilling on Pennsylvania public lands. 
The Pennsylvania Environmental Defense Foundation was founded around 2001 and is run out of Camp Hill, Pennsylvania. The Foundation was established to increase environmental regulations and restrict the development of natural resources. 
Most of the lawsuits filed by the Foundation are based on Pennsylvania’s unique “environmental amendment” to the state constitution. The constitutional amendment, adopted in 1971, mandates that the state government manage Pennsylvania’s resources as a trustee, not as a proprietor. It also guarantees clean water, clean air, and environmental protections. The amendment also holds that the natural resources of the state are the property of all people. 
The Foundation has used this amendment to support left-of-center environmentalist regulations. In 2012, the Foundation filed a lawsuit which sought to require that all money generated from oil and gas drilling on public lands be spent only on preserving those lands. The Foundation sued the state in order to block the development of new oil and gas drilling in the state, claiming that the new oil and gas developments in the Marcellus Shale natural gas boom violated the state’s environmental amendment. 
The lawsuit claimed that spending revenue gained from oil and gas drilling on public lands on anything other than conserving public lands violated the environmental amendment to the state constitution.  In 2017, the Pennsylvania Supreme Court ruled in favor of the Foundation, holding that the state was violating the environmental amendment by using revenue from oil and gas drilling for other purposes. 
In an August 2020 opinion article, Foundation president Ron Evans accused the state of not adhering to the ruling. He demanded that the state cease all new oil and gas drilling on public lands. He also demanded the state stop diverting money generated by existing oil and gas drilling to the state’s general fund. 
The Foundation has no employees and relies on volunteers.  The Foundation is governed by a board of trustees who are elected by the organization’s membership to represent various regions of Pennsylvania.  Ron Evans is the president and treasurer of the organization. 
In 2018, the Foundation generated $29,364 in revenue and spent $22,513. It had $20,204 in assets.