( CNN ) -- Water testing by a private environmental engineering firm has discovered toxic chemicals in wells in a township in Susquehanna County , Pennsylvania . Victoria Switzer , a resident of the northeastern Pennsylvania township of Dimock , revealed the results of the water tests from her well this week at an Environmental Protection Agency hearing on hydraulic fracturing in Binghamton , New York . Hydraulic fracturing , or `` fracking , '' is a controversial process used to extract natural gas from deep underground . Critics say chemicals used in the process can be injected into groundwater . How fracking works . Farnham & Associates confirmed that ethylene glycol , propylene glycol and toluene were present in her water , Switzer said . `` I 'm fighting for my home , '' Switzer said Thursday . `` Has n't this proven that [ fracking ] has n't been done safely ? '' The contaminated Dimock wells are in the Marcellus shale formation underneath parts of Pennsylvania , New York , West Virginia and Ohio , one of the largest natural gas deposits in the nation . The profitable natural gas reserve is attracting a flurry of gas companies wanting to drill . Fracking yields fuel , fear in Northeast . The tests , which were verified by three certified laboratories , found chemicals in the majority of samples taken from water wells in Dimock , said Daniel Farnham , president of Farnham & Associates , based in Scranton , Pennsylvania . `` For anybody to say this was occurring prior to drilling is ludicrous , '' Farnham said Friday . `` The water was not like this before . '' In 2008 , Farnham was contracted by Cabot Oil and Gas Corp. , the company working in the Dimock area , to perform pre-drilling tests on numerous wells in Susquehanna County , he said , adding that he did not test for nor discover ethylene glycol , propylene glycol and toluene . Despite his latest findings , however , Farnham said he can not reach any conclusions about the source of the chemical compounds found in the drinking water wells . `` Unfortunately no one can say that right now , until there is a way to track frac fluids , '' he said . `` And I think the gas companies know that . '' Ethylene glycol , propylene glycol and toluene are on the list posted on the Pennsylvania Department of Environmental Protection 's website of chemicals used by hydraulic fracturing companies in the state . But George Stark , a spokesman for Cabot Oil and Gas Corp. , said his company does not use the chemicals discovered by Farnham & Associates . `` When we look at the ingredients we use in fracking and completing of wells , these chemicals are not found . Toluene is not at all used , '' Stark said . `` If you look at what Dan said , he found these and he ca n't trace these to fracking . `` The fact is that we do n't use these chemicals , '' Stark said . The chemicals have a number of common applications and appear in products ranging from toothpaste to antifreeze , Farnham said . But they can be toxic in higher concentrations . The Department of Environmental Protection is conducting its own water tests across Dimock , spokesman Tom Rathbun said . `` We want to see if our findings agree with Farnham , '' Rathbun said . `` We want to see if we can duplicate it . '' Department water tests in April across Dimock for ethylene glycol and propylene glycol were negative , and the agency is testing for `` toluene and a host of other constituents , '' he said . On Friday , Rathbun said that Department of Environmental Protection Secretary John Hanger plans to make a `` major announcement '' regarding water supplies in Dimock at the end of September . He would not elaborate about the details of the announcement . The Environmental Protection Agency concluded its final hydraulic fracturing hearing on Wednesday in Binghamton . The EPA plans to begin a study in January and release initial results by late 2012 . Switzer is among a group of Dimock residents who sued Houston-based Cabot Oil and Gas in November , alleging that the company contaminated their well water with methane gas and other contaminates . In hydraulic fracturing , drillers pump large amounts of water mixed with sand and chemicals into the shale formation thousands of feet underground under high pressure . Fracturing the shale around the well then allows the natural gas to flow freely . `` This industry is cradle-to-grave , '' Switzer said . `` And this baby has teeth . ''
Tests show toxic chemicals in oil wells in northeastern India . Resident says it is controversial hydraulic technology is not safe . Drilling technology says it does not use those chemicals .