Here are 4 myths about fracking that need dispelling

As the debate over shale gas intensifies David Cameron has called for an end to myths surrounding the process of hydraulic fracturing, commonly known as fracking.

Here are four you might be thinking of.

1. Your water can be set on fire

In a scene from the anti-fracking film Gasland, one of the participants who lives near shale gas wells turns on the tap in his home and holds a match close to the flow of water which proceeds to burst into flames. This has led to fears that Britain's faucets may soon be turned into fountains of fire.

Unfortunately for fracking opponents, the residents of the neighbourhood in which the scene was filmed have been able to light their water since the 1930s, long before people began producing natural gas in the area.

The area was tested by the Colorado Department of Natural Resources, which reported to the resident: "There are no indications of any oil & gas related impacts to your well water."

2. Poison water

Environmental groups have claimed that fracking can lead to severe contamination of groundwater. However, the number of cases where aquifers have been contaminated as a result of fracking amounts to a grand total of zero.

After an investigation in rural Pennsylvania the Environmental Protection Agency (EPA), not an organisation noted for its support of fossil fuel production, concluded that there was no evidence that hydraulic fracturing had contaminated private water wells. Their conclusions were supported by two studies from research firm Gradient, which said groundwater contamination from fracking was "not physically plausible."

3. Fracking uses too much water

It can take up to 7m gallons of water to frack a single well. This may sound like an excessive amount but it pales in comparison to our other uses for water.

A study by Carnegie Mellon University showed that the amount of water needed to frack all 2916 wells of Pennsylvania's Marcellus formation, was equivalent to the drinking water used by just one city - Pittsburgh.

The EPA estimate that between 70bn and 140bn gallons was used for fracking in 2011. Americans used 20 times more water to maintain their lawns in the same period.

4. Fracking is new and untested

Fracking is far from a new and untried technology. 1947 saw the first fracked well and more than 2.5m wells have been fracked since.