ExxonMobil, the world’s largest energy company, has been charged by the state of Pennsylvania for dumping tens of thousands of gallons of fracking wastewater at a drilling site in 2010, and violating the Clean Water Act. XTO Energy, the Exxon subsidiary responsible for the atrocity, agreed to several fines, but Exxon has contested criminal charges and says that there is “no lasting environmental impact.”

The attorney general’s office filed criminal charges against the Exxon company for illegally dumping over 50,000 gallons of toxic wastewater from a Marcellus Shale gas well site in Penn Township, Lycoming County, Pennsylvania.

Attorney General Kathleen Kane said the toxic wastewater made its way to an unnamed tributary of Sugar Run, Pennsylvania. The Pennsylvania Department of Environmental Protection (DEP) also required the excavation and removal of over 3,000 tons of contaminated soil from XTO Energy’s Marquardt well site in Penn Township.

A grand jury found that XTO hired a company to recycle its toxic wastewater at the Marquardt site, but, after a one-week period, XTO directed the company to remove its processing equipment and transport it to another site in West Virginia. Yet, “XTO allegedly continued to transport and store gas well waste water at the Marquardt site despite not having the proper equipment on site to safely store or process it,” according to the attorney general’s office.

During an unscheduled visit by the DEP, inspectors found a plug had been removed from one of the tanks, allowing toxic wastewater to run into the ground. Despite its company’s negligence, Exxon now says that charging XTO “under these circumstances could discourage good environmental practices,” Bloomberg reports. XTO called the charges “unwarranted” and “legally baseless.”

In July, XTO agreed to pay what it called “reasonable civil penalties,” including $20 million to improve wastewater management at its wells, according to Reuters. But company officials feel criminal charges are “an abuse of prosecutorial discretion.”

Hydraulic fracturing, fracking, creates wastewater products also known as “flowback” and “produced water.” Both types of wastewater contain harmful pollutants, which can be toxic to humans and animals and can be radioactive and corrosive. The Natural Resources Defense Council (NRDC) reports that wastewater can “damage ecosystem health by depleting oxygen… [and] can interact with disinfectants at drinking water plants to form cancer-causing chemicals.”

Most natural gas drilling of the Marcellus Shale has occurred in Pennsylvania. Residents of the state have experienced contaminated water tables and health issues from exposure to toxins.

Doctors in the state must operate under a fracking “gag rule,” which allows them to access information about trade-secret chemicals used in the fracking process in order to treat their patients, but prevents them from discussing those ingredients, even with other doctors.

Alisha is a writer and researcher with Ring of Fire. Follow her on Twitter @childoftheearth.