Pennsylvania roads are being coated in radioactive wastewater—here's why

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Add as preferred source Pennsylvania's roughly 100,000 oil and gas wells produce wastewater that's many times saltier than seawater and contains radium, a known carcinogen . For decades, that saltwater, called brine , was spread on dirt and gravel roads across the state to control dust and on paved roads to melt ice.

The state Department of Environmental Protection halted the practice in 2018, but residents continue to report oil and gas brine being spread in their communities. Now, a permit issued by the Department of Environmental Protection in May 2026 could open a new path for oil and gas well wastewater to be sold as a commercial product that road maintenance operators or snow removal businesses could purchase.

William Burgos and Nathaniel Warner , professors of environmental engineering at Penn State, have spent years testing whether oil and gas brine actually works as a road dust suppressant. Road dust is an issue because fine particles generated by traffic can get into residents' lungs and cause respiratory issues . The dust also reduces visibility , which can lead to accidents. Burgos and Warner spoke with The Conversation U.S.'s Pittsburgh editor, Cassandra Stone, about what's in the brine, why it fails at the job it's supposed to do and what the new permit means for Pennsylvanians.

Oil and gas wells produce a significant amount of water, called produced water or brine , along with the oil and gas they recover. In northwestern Pennsylvania, the ratio is around eight barrels of water per barrel of oil. The water is very salty—often 5–10 times as salty as seawater. It is generated from both conventional oil and gas wells and unconventional, or "fracked," gas wells—such as those used to extract natural gas from the Marcellus and Utica shales in Pennsylvania.

The Pennsylvania Department of Environmental Protection banned using brine from fracked gas wells for dust suppression or anti-icing in 2016 and issued a moratorium halting the road spreading of conventional oil and gas brine in 2018. Well operators had previously provided the brine to local townships for free.

Lots of calcium, sodium and chloride, but also radium—a radioactive element and known human carcinogen —as well as petroleum hydrocarbons and lead.

Most of these contaminants wash off the road and end up in streams and sediments . The salt can harm fish and other wildlife and corrode bridges and automobiles. Salt from roads can also enter nearby drinking water wells .

Geochemically, there is no obvious reason. Brines from conventional and unconventional wells are chemically very similar: Both are extremely salty and radioactive, and both contain heavy metals and organic contaminants.

For example, in Pennsylvania , the combined activity of two radioactive forms of radium averaged 2,000 picocuries per liter in conventional oil and gas brine and 1,800 picocuries per liter in unconventional Marcellus Shale brine.

There are numerous federal regulations from different agencies governing discharges of radium into the environment, but many do not directly apply to oil and gas wastes. The EPA tries to follow the principle that radioactivity exposure should be " as low as reasonably achievable ," also known as ALARA . Its drinking water standard for combined radium activity is 5 picocuries per liter .

Obviously, people are not drinking the oil and gas brine directly, but the problem is that we don't know where the radium ends up after the brine has been applied to the road. It mostly washes off with runoff, but radium dried onto the road could be remobilized as dust that someone inhales, or radium could accumulate in game fish eaten by fishermen.

Operationally, unconventional gas wells produce much more water than conventional oil wells, which may be the reason for the additional restrictions on disposal options. Historically, the two industries emerged under very different rules. Environmental regulations were already in place in 2008 when the unconventional Marcellus Shale gas boom began, but conventional drilling dates to the Drake well in 1859—long before modern environmental oversight existed.

Produced water is regulated by the Office of Oil and Gas Management within the Pennsylvania Department of Environmental Protection. Most regulations rely on self-reporting by well operators. Operators of conventional wells are required to report the volumes of oil, gas and brine produced from each well every year.

If an operator wants to classify its brine as a coproduct and use it for some purpose, it must submit a form to the department's Bureau of Waste Management. There are no requirements to measure radium concentrations or demonstrate that the brine works for its new intended use.

No. We designed multiple studies to determine whether oil and gas brine can suppress road dust. In the first, we used a laboratory method to measure the amount of dust generated from road material treated with various dust suppressants. Oil and gas brine was little or no more effective than rainwater—and in some cases, it even increased dust compared with rainwater.

We also conducted large-scale laboratory experiments and found that most contaminants in oil and gas brine, such as radium, completely washed off treated roads after a typical rainstorm. More road material washed off roadbeds treated with oil and gas brine than those treated with calcium chloride, a commercial dust suppressant. Roads treated with oil and gas brine will not suppress dust, and they degrade faster and cost more to repair than those treated with plain water.

In May 2026, the department issued a permit for a brine production well drilled into an oil and gas formation.

This means that the same radioactive oil and gas brine wastewater ...

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