A final report on foul-tasting well water in a rural Wyoming community has found that hydraulic fracturing probably didn't cause the problem.
The U.S. Environmental Protection Agency touched off a national backlash in 2011 when it said fracking likely was behind the groundwater problem in Pavillion.
The controversy came as the process boosted oil and gas production and drove down costs for transportation and heating.
The EPA never finalized its Pavillion report and instead handed the investigation over to Wyoming.
After a two-year study, Wyoming officials said Thursday that bacteria might have tainted the wells in the Pavillion area.
Hydraulic fracturing is the process of injecting pressurized water, sand and chemicals underground to break open oil and gas deposits.