The boom in natural-gas production from the U.S. Marcellus Shale continued this year. Previous doubts about the size of the vast resource were dispelled as data showed the shale becoming the most productive natural-gas field in the country, despite a substantial slowing of drilling. According to government energy reports, Marcellus wells primarily in Pennsylvania and West Virginia now produce 7 billion cubic feet of gas per day, about 25 percent of all shale-gas production nationally and nearly double the Marcellus production of 2011. The Marcellus could contain “almost half of the current proven natural-gas reserves in the U.S.," said a report from Standard & Poor's, while other experts noted that combination of resource, cost, and location is altering natural-gas prices and market trends, as gas that used to come from the Gulf of Mexico coast or Canada to feed the power-hungry northeastern United States now comes from Marcellus producers. The Marcellus Shale lies under parts of Pennsylvania, West Virginia, Ohio, Maryland, and New York state. The procedure called hydraulic fracturing (fracking) has made it possible to tap into deep reserves of oil and natural gas, but the boom in shale-gas fracking has raised concerns about pollution. Large volumes of water, along with sand and some hazardous chemicals, are injected underground to break apart rock to free the oil and gas. The energy industry and many federal and state officials say the practice is safe when done properly, but environmental groups and some scientists say there has not been enough research on the issue.
