07/02/2014 11:53 GMT | Updated 09/04/2014 06:59 BST

Why Fracking Threatens Farmers and Food Safety

The announcement this week by the gas company Cuadrilla that it wants to drill and frack up to eight new wells in Lancashire has alarmed local people and green campaigners alike; they are worried about the impact of hydraulic fracturing - the controversial technique which involves injecting, at high pressure, a mixture of water, sand and chemicals into the earth to release shale gas - on the area's countryside and wider environment.

Few concerns have so far been raised about the potential implications for farming and food production, whether in Lancashire or beyond. But farmers, and indeed all of us, should be very worried indeed; alarming research has linked fracking to illnesses in livestock and raised concerns about food safety.

As I reported for The Ecologist and The Independent, the academics behind this research linking fracking to sickness and reproductive problems in livestock - including failure to breed and stillbirths - have called on the UK authorities to halt fracking until further research has been carried out and the safety and health of farm animals can be guaranteed.

Robert Oswald, a professor of molecular medicine at Cornell University, and Michelle Bamberger, a veterinarian, in 2012 published the first-peer reviewed research suggesting links between fracking and sickness in farm animals. They compiled evidence from twenty four farmers in six different states whose livestock suffered reproductive, gastrointestinal and neurological problems after exposure to fracking chemicals in the water or air.

Among the case studies uncovered were seventeen cows that died of suspected respiratory failure after exposure to spilled frack fluid in Louisiana, and around seventy cows in Pennsylvania that died after 140 animals were reportedly exposed to frack wastewater - of the surviving cows, less than a dozen produced calves, and only three survived. Another Pennsylvania herd recorded a 50% stillbirth rate after cows had grazed in fields contaminated by fracking chemicals spilling from a waste pit; the following year saw an abnormally skewed sex ratio, with ten female and two male calf births, as opposed to the typical 50:50 ratio.

Oswald told me that if fracking goes ahead in the UK, 'farmers living in intensively drilled areas should be very concerned about potential exposures of their crops and herds to shale gas contaminants in the water, air and soil.'

He also said it was vital British farmers near to fracking sites are made aware of which chemicals are being used: 'Farmers have a right to know what their families and their herds are being exposed to. That is, the components of fracturing fluids and drilling muds to be used in a well near a farm should be reported in advance of drilling to the farmers - with no [exemptions] for proprietary information or trade secrets.

'This would allow testing [of] air, water and soil prior to the commencement of drilling for those specific components. Complete [...] testing done before drilling operations begin, during and after drilling for the components of fracturing fluids, drilling muds and expected components released by the shale [gas],' he said.

In the US, the researchers found, it was difficult to obtain data on the links between fracking chemicals and health impacts on livestock because much of the information is the subject of non-disclosure agreements or proprietorial exclusions.

Campaigners say an array of additives are added to frack fluid, including some linked to cancer. They claim that kerosene and diesel fuel, which can contain benzene, ethylbenzene, toluene, xylene, naphthalene - and other substances - are reportedly used, as are methanol and formaldehyde, ethylene glycol, hydrochloric acid and sodium hydroxide, among many others. Lead and crystalline silica have also been cited as ingredients in frack fluid.

Oswald and Bamberger believe fracking in the UK should be banned until research into the possible health effects of exposure to the chemicals used is undertaken: 'First, we need to know the identities of all the chemicals used in drilling and hydraulic fracturing fluids. We need to know the MCLs (Maximum Contaminant Level) for the chemical additives and wastewater constituents. We need to know the health effects of exposure to multiple toxicants because MCLs are set for exposures to one chemical only and not combinations of chemicals,' Oswald said.

'We are reporting short-term health changes, but no one knows what the long term health changes may be, especially those caused by low doses of chemicals.'

Although animals that have died on-farm shouldn't ordinarily be entering the human food chain, the academics believe it is possible that food safety could be compromised: 'It's important to remember that although only one of the herds we documented was quarantined, all the herds were exposed to affected air, water and or soil. This is a major concern to us because we documented cases where farms in areas with known exposures are still producing vegetable crops, meat, eggs and dairy products without testing of the plants, animals or the products,' said Oswald.

And it's not just livestock at risk. The US journalist Elizabeth Royte highlighted the potentially disturbing health impacts of activities linked with gas and oil extraction on farmers themselves, focussing on the case of Jacki Schilke, a cattle farmer from North Dakota. Schilke believes her health - and that of her cattle; five cows dropped dead - suffered after the onset of fracking at more than thirty gas and oil wells close to her ranch.

The farmer suffered chronic pain in her lungs, back pain attributed to overworked kidneys as well as rashes that lasted for over a year. Air testing confirmed higher than normal levels of chemical compounds including benzene, butane and chloroform, all associated with fracking and drilling, and her well tested high for other compounds. 'I realised that this place is killing me and my cattle,' the farmer told Royte.

Late last year one Lancashire dairy farmer did put his head above the parapet and joined forces with Greenpeace to launch a legal challenge to fracking. Andrew Pemberton said he had backed the campaign because his livelihood would be destroyed if the local water became contaminated by fracking.

And in West Sussex, where rural communities around Wisborough Green, Kirdford and Fernhurst are battling plans for exploratory drilling, another farmer opposed to fracking told me bluntly: 'We don't know enough about it [fracking], nobody does. Not us or them. If they get it right, fine, but if it goes wrong and we end up with pollution and sick animals, it'll be us, not [the gas industry] that will suffer.'

Other farmers would do well to heed such words - their livelihoods and health may yet depend on it.

Andrew Wasley's book, The Ecologist Guide To Food, published by Leaping Hare, is out now