DENNIS BARTON is right to be worried about fracking, but earth tremors are unlikely to be an issue in York (Letters, February 10).

Firstly, the small earthquakes he mentions in Texas have been caused by injection wells, not fracking. Injection wells are old oil and gas wells used to dispose of the millions of gallons of toxic water which results from fracking.

In the UK, we don’t have many easily accessible old wells. However, what do we do with millions of gallons of water contaminated with fracking chemicals, salt and radioactivity?

Some of the waste from the Blackpool tests was driven to Manchester and put through a sewage works – and there are now worries that the radioactivity could contaminate the Manchester Ship Canal.

We should be concerned about the numbers of lorry movements, the industrialisation of our countryside, the potential for our aquifers and groundwater to be polluted, and the powerful greenhouse gases which leak from the sites and are emitted when the gas is burnt.

These will add to climate chaos, helping to exacerbate powerful storms and flooding.

If anyone wants to find out more, there’s a public meeting on Monday, February 17 at the Priory St Centre, at 7pm with a film and panel debate.

John Cossham, Frack-Free York, Our Clean Energy Future, Hull Road, York.

• KEITH ANDERSON says that scare stories on fracking don’t add up (Letters, February 12), presumably because of his personal experience of fracking near to his home. I doubt if this happened in Dunnington.

If the first fracking extraction took place close to the home of our Prime Minister or his Energy Secretary and it was successful with no adverse effects, then we would all know that this system is safe.

Is it likely that anyone in government will ever lead by example?

Wilf Arnott, Hobmoor Terrace, York.

• READING Dennis Barton’s letter of February 10 – “Fracking blamed for earthquakes” – I wonder what would happen in an area that had the mining industry from the late 16th century or early 1700s until the 1960s to 1980s, when the mines were eventually closed. The underground is riddled with coal-mined tunnels.

The area I am thinking about is my birthplace in Co Durham, where there were pitheads everywhere.

Could fracking cause tunnel collapse and more earth movement than would be if left to nature? It would be interesting to know.

Maureen Robinson, Broadway, York.