Millions of barrels of salty, toxic wastewater from natural-gas wells in Pennsylvania are coming into Ohio despite efforts to keep it at bay.

In June 2010, Ohio quadrupled the fees that out-of-state haulers must pay to dump brine into 170 disposal wells.

Ohio officials thought that raising the fees to 20 cents per barrel from 5 cents would help keep the brine in Pennsylvania, where drilling has exploded since the discovery of huge gas deposits deep in Marcellus shale. Ohio wants to keep its injection wells open for Ohio brine, which also might explode in volume if the state’s own shale begins to give up natural gas.

But then, Pennsylvania officials told 27 sewage-treatment plants to stop dumping brine into streams. The state’s geology doesn’t support brine-injection wells.

Ohio’s does.

From January through March, nearly half the brine that went into disposal wells in Ohio came from Pennsylvania and other states, said Tom Tomastik, chief of the Ohio Department of Natural Resources’ disposal-well program.

That’s 1.18 million barrels of brine, enough to fill 76 Olympic-sized swimming pools.

“It’s a dramatic increase,” Tomastik said. “No one was really foreseeing Pennsylvania shutting down its treatment plants.”

None of this sits well with environmental groups that consider brine – and the hydraulic fracturing process used to draw gas from the ground – a threat to groundwater and drinking water.

Trent Dougherty, staff attorney with the Ohio Environmental Council, said the state should examine what’s in the brine before it is pumped underground.

“This is a brand-new set of chemicals and constituents that are going to be put in these wells,” Dougherty said. “We need more study to make sure what’s going in there should be allowed to go in there.”

In hydraulic fracturing, or “fracking,” drillers inject millions of gallons of pressurized water laced with industrial chemicals into wells to break apart the shale and help release gas.

About 15 percent of that water comes back up, tainted with salt, drilling chemicals and hazardous metals. After they’re “fracked,” the wells continue to produce brine that contains higher concentrations of salt, metals and minerals.

Pennsylvania sewage plants dumped so much brine that it became a threat to drinking water. The brine contains high levels of bromides, which help form hazardous compounds called trihalomethanes in drinking water.

Pennsylvania Gov. Tom Corbett made it clear to the plants to stop dumping brine. Kevin Sunday, spokesman for the state’s Department of Environmental Protection, said all the plants have stopped.

Tomastik said Ohio’s disposal wells are safe. “We have not had any subsurface contamination of groundwater since we took over the program in 1983,” he said.

Pennsylvania’s loss was great for waste haulers such as Kim Parrott, owner of Bessemer Supply Inc. in Bessemer, Pa.

He said his two 100-barrel tanker trucks used to deliver Pennsylvania brine to Ohio injection wells three days a week. “Now, they work about six days a week,” Parrott said.