Academics from various universities in the U.S. have teamed up to study the health effects of hydraulic fracturing used to extract natural gas.

University of Pennsylvania's Center of Excellence in Environmental Toxicology is collaborating with universities such as Columbia, John Hopkins and North Carolina for this research project.

Fracking uses powerful injections of chemical fluids and sand to crack deep-seated rocks and release gas and oil deposits.

This technique, used to release gas, has attracted a lot of criticism from environmentalists as it leads to contamination of ground water, air pollution and possible health damages when it comes in contact with human skin.

As a result, some countries have either banned or suspended it.

The research team will study the reports of nausea, headaches and breathing difficulties from people who live near natural gas drilling sites, compressor stations or wastewater pits.

The project aims to bring an end to the debate of whether fracking is connected to environmental contamination and health hazards such as cancer and birth defects.

"There is an enormous amount of rhetoric on both sides," Trevor M. Penning, head of the Penn toxicology center told The New York Times. "We felt that because we are situated in Pennsylvania, we had a duty to get on top of what was known and what was not known."

Some of the questions to be answered include:

- Percentage of toxicity in 'flow back water' that arises from gas wells.

- Chemicals and their combinations present in the 'flow back water' and its effects on health.

- Whether air quality is reduced by flaring of waste gases.

- If extensive use of diesel fuel trucks, drills and compressor stations is reducing the air quality.

The first project included a survey conducted on the residents in the Marcellus Shale regions of Pennsylvania to deduce whether their health symptoms were connected to local gas drilling.

Results are expected to be out by mid-February.

Other projects will follow suit once they obtain the finance from the National Institute of Environmental Health Sciences.

Around five years ago, shale gas reserves were discovered in the country, an unconventional source of energy, which is set to rule the global markets in the years to come.