The environmental lobby, energized by the Pennsylvania Supreme Court's decision last month striking down parts of the state's gas-drilling law, told the senators the court ruling requires the legislature to conduct an environmental impact assessment of the acid-mine bill.
In a state polarized over fracking, the opposition seems as much driven by suspicion that the industry is wrapping itself in the mantle of doing something environmentally positive.
"Everybody believes we have to clean up AMD," said David Masur, president of PennEnvironment. "There's no debate there. But this is not the way to do it."
The bill is sponsored by Sen. Richard A. Kasunic, a Fayette County Democrat whose district has been hard hit by drainage from abandoned coal mines. The Senate Committee on Environmental Resources and Energy unanimously approved the measure last year.
"This innovative approach to the treatment and use of acid-mine water is both cost-effective and environmentally responsible," Kasunic said at the time, calling it a "win-win proposition."
But support appears to be eroding. A split Senate Appropriations Committee on Monday approved the measure, 16-9. Five Republicans and four Democrats voted against the measure, including one of its cosponsors, Sen. Jim Ferlo, an Allegheny County Democrat.
Sen. Vincent Hughes of Philadelphia, the highest-ranking Democrat on the Appropriations Committee, said he voted for the bill to "further the process," but expressed hope the language would be revised.
Contaminated water from mines typically contains large amounts of metals, like iron, that give it a reddish hue. Treated, it could displace fresh water now used in hydraulic fracturing, the process by which water, sand, and chemicals are pumped under enormous pressure into a shale formation to create tiny cracks that allow natural gas to flow.
But gas producers are reluctant to use contaminated water out of concern they would inherit responsibility for perpetual treatment of the waste at its source. Gov. Corbett's Marcellus Shale Advisory Commission in 2011 recommended the legislature grant liability protections to the industry to encourage AMD reuse.
Kasunic's proposal would expand the Environmental Good Samaritan Act of 1999, which already limits the liability of people involved in the voluntary abatement of acid-mine drainage to allow the state Department of Environmental Protection to grant legal immunity to parties with approved mine-water treatment programs.
Jordan B. Yeager, the Doylestown lawyer who was on the legal team that won the landmark state Supreme Court decision against the gas-drilling law, has criticized the bill in several legal memos that have formed the basis of the complaints from environmental activists. He said the bill would do nothing to abate acid-mine drainage.
The Environmental Good Samaritan Act originally envisioned liability protections for those working to address mine discharge at or near its source, said Tracy Carluccio, deputy director of the Delaware Riverkeeper Network. Extending those protections to entities that would transport water from the mine sites is a "perversion" of the bill's original intent, she said.
William S. Dando, Kasunic's chief of staff, said the bill's language specifically did not grant immunity for "unlawful spills or releases of mine drainage or mine pool water."
The Rand Corp., which explored the issue in a 2012 report commissioned by the Marcellus Shale Coalition, anticipated the complications of tinkering with the complex laws governing the treatment of mine water.
It said any regulatory changes must be approached carefully to "avoid modifying existing regulations in a manner that is not broadly beneficial or that is even harmful to the environment in some other way."
Several shale drillers have already used "mine-influenced water" in fracturing.
Seneca Resources, which is drilling in northern Pennsylvania, draws contaminated water directly out of a creek in Tioga State Forest, said Doug Kepler, Seneca vice president of environmental engineering. Because Seneca is not withdrawing the water from a mine and is not treating the water, it does not assume liability for treating the mine discharges.
"The mine water is a viable source to frack with," he said.
Kepler, a biologist, agrees Seneca's use of the contaminated water does not correct the problem. It only temporarily reduces the pollutants from one mine in one stream, he said.
"It was a polluted source rather than a fresh source, which made it nice from my perspective," Kepler said. "We could have less impact on freshwater resources."