Sherry Vargson ignites the tap water in her kitchen in Granville Summit, Pennsylvania, in 2012. Her family’s farm is in the Marcellus Shale region, where the fracking rigs have contributed to increased methane in the water supply. Melanie Stetson Freeman / The Christian Science Monitor / Getty Images

D.J. Parker has been selling methane-trapping systems to oil and gas producers for over 30 years, and as unconventional drilling technologies like hydraulic fracturing, or fracking, have skyrocketed across the U.S., particularly under Barack Obama’s administration, Parker’s business has grown.

“Over the last 15 years we’ve seen a marked increase in voluntarily capturing emissions,” said Parker, the vice president of operations at Tescorp. “Then in 2012 inquiries really increased … There are two things driving it. One’s economic. The other’s the [Environmental Protection Agency].”

The EPA has become increasingly concerned with reducing the methane emissions inherent in the oil and gas production and distribution process. In 2012 the agency announced that by 2015, drillers would be required to use green completion technology to capture methane during the drilling completion process — the stage after drilling, when oil and gas starts to flow out of the well. Vapor recovery systems turn methane into liquid that can be sold, providing an economic incentive.

On Sept. 30 the EPA announced that its new requirements appeared to be making a difference even before they become law on Jan 1. Through its greenhouse gas reporting program, which keeps track of the self-reported emissions of the country’s biggest emitters — mainly factories and oil and gas production infrastructure — the agency found that greenhouse gas emissions from petroleum and natural gas facilities fell 12 percent from 2011 to 2013. The most significant reductions came from hydraulically fractured wells, which saw a 73 percent reduction in methane emissions in that period.

In a report that was otherwise characterized by very slight reductions in other sectors and by an overall increase in emissions nationwide, the 73 percent drop provided a rare bright spot for an agency under pressure from the Obama administration to significantly reduce greenhouse gas emissions over the coming decades.

The numbers also seemed to vindicate Obama and other fracking supporters, who contend that, if regulated sufficiently, fracked natural gas can serve as a bridge between more carbon-intensive energy sources and a renewable energy future.

The EPA highlighted the decrease in a press release, and industry groups hailed the reduction as a success.

“We want to capture as much [methane] product as possible, so there’s a cost benefit to this,” said Erica Bowman, the vice president of research and policy analysis at America’s Natural Gas Alliance, one of the industry’s largest trade groups. “But also because of the rules promulgated in 2012, you’ve seen an incredible move in our industry to get into compliance before the regulations come into effect.”

But the reduction tells only part of the story. Buried deeper in the EPA’s report was data showing that emissions at other stages in the fracking process — from the venting of gas at the drill sites to the pneumatic pumps used in transporting gas — had increased significantly.

The mixed news from the EPA and the fact that it highlighted only some of the fracking data in its press release provide a glimpse into one of the most contentious debates in the environmental community. There’s a long-running disagreement among the EPA, the fracking industry, many scientists and environmentalists over how much methane is leaking from fracked wells.

“The EPA’s [73 percent] number is accurate insofar as it represents reduction in methane emissions during completions, but it doesn’t really speak to the whole picture,” said Mark Brownstein, the associate vice president of the U.S. Climate and Energy Program at the Environmental Defense Fund. “I think the EPA was stretching for a good story and confused a lot of people in the process.”

This isn’t the first time the EPA has gotten into hot water with environmentalists and scientists over which numbers it chooses when evaluating the effects of fracking

The EPA uses relatively low estimates of how much methane leaks during the natural gas production process. The agency’s estimates are based on a bottom-up approach to monitoring, in which data from individual sources is collected largely through voluntary reporting from the industry and analyzed to paint a broad picture of U.S. methane emissions. Through this method, the EPA has estimated that about 1.2 percent of the gas produced by fracking leaks into the atmosphere during the process.

But a growing list of studies — most of them using top-down approaches, in which monitoring equipment measures emissions over a wide area — throw the EPA’s estimates into question.

“Consistently, studies show [methane leaks] are between 4 and 17 percent,” said Seth B.C. Shonkoff, a visiting scholar at the University of California at Berkeley and the executive director at science policy think tank PSE Healthy Energy. “The most authoritative say the EPA underestimates methane emissions by about 50 percent. It seems the EPA is forgetting this big field of independent science.”

A scientific review led by Adam Brandt, an assistant professor of energy resources engineering at Stanford University, also found that most studies on the topic estimate natural gas methane leakage to be significantly higher than the EPA’s estimates.

The most recent study on the issue, lead by Oliver Schneising at the Institute of Environmental Physics at the University of Bremen in Germany, used satellite technology to determine the average methane emissions over two of the United States’ biggest shale fields — one in Texas and one in North Dakota. The study found that methane leakage rates were about 10 percent in each region, several times higher than the EPA estimates.

The EPA’s numbers triggered a report from the agency’s inspector general last year recommending that the agency look into revising how it collects and interprets data on natural gas and oil production.

In an email to Al Jazeera, an EPA representative wrote, “EPA is aware of a number of studies calculating methane emissions that differ from EPA’s estimates … EPA is considering how information from such studies can be used to update comprehensive national estimates of methane emissions from the oil and gas sector.”

The challenge to find an accurate number is increasing, as the oil and gas industry is growing, diversifying its methods and expanding to new areas.

“It’s a very large and diverse industry. There are 500,000 gas wells, a couple million miles of distribution lines, lots of operators and a lot of different technologies,” said Brandt. “So it’s quite a problem to say anything about the industry as a whole.”

But for environmentalists and many scientists, getting accurate (or at least more accurate) information about methane emissions is about more than scientific intrigue. Methane is several dozen times more effective at trapping heat than carbon dioxide, though it dissipates more quickly in the atmosphere.

If the U.S. wants to see climate benefits from increases in natural gas over the next 20 years and decreases in dirtier fuels like coal, methane emissions from natural gas production and infrastructure have to be kept below 3.2 percent, according to a 2012 study by the Environmental Defense Fund and several universities.

If the EPA estimates about gas and oil production are right, then natural gas is indeed a cleaner technology than coal and oil. But the studies suggesting the number may be much higher are alarming to environmentalists.

“Methane emissions will most likely will continue to be underestimated,” said Hugh MacMillan, a senior researcher at Food and Water Watch, based in Washington, D.C. “The EPA needs to reconcile their reporting with the folks … who are actually estimating what’s in the atmosphere.