Energy researchers defended fracking - a controversial method of natural gas extraction from underground rocks - at an international meeting Thursday, even though opponents maintain the process pollutes groundwater and causes earthquakes.

Investigators blamed underground water pollution and other environmental problems associated with fracking on improper techniques instead of the hydraulic fracturing extraction process itself.

The bottom line conclusion of our study is that in the states we investigated, we found no evidence that hydraulic fracturing itself had contaminated shallow groundwater, Charles Groat, associate director of the Energy Institute at the University of Texas and lead researcher of the study said at the American Association for the Advancement of Science conference on Thursday.

The researchers examined four states with major fracking operations: Texas, Louisiana, Pennsylvania and New York. The investigators said they found no evidence that fracking necessarily caused groundwater contamination.

There is at present little or no evidence of groundwater contamination from hydraulic fracturing, the authors wrote. No evidence of chemicals from hydraulic fracturing fluid has been found in aquifers as a result of fracturing operation.

Instead, improper techniques are to blame for the dangers associated with the process.

Poor practices are poor practices and they need to be identified and need to be penalized so they are not carried on, Groat told the BBC.

Poor practices, however, are the industry standard, according to Food & Water Watch, an anti-fracking advocacy group. High-pressure fluids used in fracking can pollute groundwater and cause natural gas to migrate into local water supplies, the group maintained.

The byproducts of the fracturing process are toxic and are often disposed of improperly, Hugh Macmillan, senior researcher for Food & Water Watch said.

When you have this large industrial process you're going to have these incidents, he said. Some folks can't be bothered. They're just going to dump it illegally.

Issues related to fracking are overstated, according to the study, published online at the Energy Institute's website. Fracking byproducts mix with groundwater only when safety measures fail and not in typical situations, the researchers said. That kind of failure can occur in any kind of operation; it is not unique to fracking, the authors wrote.

Claims of fracking leading to natural gas in the water supply are also unfounded. In most cases, the gas was already present in the water supply before fracking began, they wrote.

One danger associated with fracking that was not addressed in the study was its relation to earthquakes.

To my knowledge, the Horn River area of northeastern British Columbia is not particularly earthquake prone, John Clague, an earth sciences professor from Simon Fraser University told the BBC. Yet there are documented observations in this area of fluid pressures causing rocks that are near the threshold of failure to slip, triggering earthquakes

Some believe that fracking caused a series of earthquakes in Ohio, according to The Associated Press. The fracking stopped as the incident undergoes an investigation.

The researchers said they plan to conduct research to look into whether fracking can cause earthquakes.

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