(CNN) -- The U.S. Environmental Protection Agency investigating drinking water contamination in Pavillion, Wyoming, found benzene and methane in wells and in groundwater, agency officials said.
At a community meeting with well owners, EPA officials revealed Tuesday they found low levels of petroleum compounds in 17 of 19 drinking water wells sampled, and that nearby shallow groundwater was contaminated with high levels of petroleum compounds such as benzene, according to the report.
The affected well owners were advised not to drink the water at the recommendation of the U.S. Department of Health and Human Services' Agency for Toxic Substances and Disease Registry, and told to use alternate sources of water for drinking and cooking, agency officials said.
Meanwhile, the EPA is working with various government partners and EnCana, a natural gas company, to provide affected residents with water and to address potential sources of the contamination, agency officials said.
The study included sampling 21 domestic wells within the area of concern, two municipal wells, plus sediment and water from a nearby creek. The EPA also sampled groundwater and soil from pit remediation sites, and produced water and condensate from five production wells operated by the primary natural gas operator in the area, agency officials said.
No health concerns were found related to inhalation exposure to chemicals while showering or using evaporative coolers, agency officials said.
The EPA has not reached any conclusions about the sources of chemical compounds found in drinking water wells, including hydraulic fracturing, or "fracking," the controversial process used to extract natural gas from underground, agency officials said.
Officials are uncertain if the contaminated shallow groundwater will migrate to the drinking water aquifer, according to the report.
"EPA will work as long as necessary to ensure that Pavillion residents have safe water," Jim Martin, EPA's regional administrator in Denver, said in a statement released Tuesday. "While our investigation continues, EPA has secured commitments from our partners to identify alternate sources of water for affected homes and to evaluate long-term solutions."
In addition to detecting several petroleum hydrocarbons, the EPA found a number of "inorganic constituents" such as sodium and sulfates in drinking and groundwater wells, according to the report.
In spring 2008, residents of Pavillion -- concerned about the quality of their drinking water -- contacted the EPA in Denver, Colorado. The agency sampled 39 individual wells (37 residential wells and two municipal wells) in March 2009 and found nitrate, arsenic and methane gas. The agency conducted the second sampling in January 2010.
Over the past week, officials from EPA and the federal agency for toxic substances met privately with individual residents to provide health information and recommendations based on well-specific sampling results, agency officials said.