Fracking may raise health risks from hormone-disrupting chemicals freed into the environment.
A study, by the University of Missouri and published in Endocrinology, looked at 12 suspected or known endocrine-disrupting chemicals. Water samples from drilling sites in the US with a record of spillages had levels of the chemicals high enough to interfere with the body’s responses to male hormones.
Little endocrine disrupter activity was found in water samples from sites where little drilling was taking place.
Dr Susan Nagel, from the University of Missouri, one of the authors of the study published in the journal Endocrinology, said: "More than 700 chemicals are used in the fracking process, and many of them disturb hormone function.
"With fracking on the rise, populations may face greater health risks from increased endocrine-disrupting chemical exposure."
Hydraulic fracturing, or fracking, uses a pressurised mixture of water and chemicals to free natural gas and oil from shale rock. It offers an enormous source of untapped energy in the UK, with trillions of cubic feet of gas said to be recoverable in parts of northern England.
However there is strong opposition to the granting of drilling licences to fracking companies. Those fighting moves to allow fracking in the UK say it poses an unacceptable environmental and health hazard.