Work has stopped at twelve coal seam gas sites in Queensland over the weekend after the discovery of asbestos.

Normally found as insulation in older buildings, the potentially deadly chemical has turned up in an unexpected place.

Asbestos fibres were identified in one of the pre-drilling fluids used for wells in the Surat Basin.

While coal seam gas extraction, often requiring the subterranean injection of chemicals in a process known as ‘fracking’, has no shortage of critics – this is the first time that asbestos has been the cause of CSG concern.

The wells in question are operated by Australian firm Origin Energy, which has blamed its international suppliers for the presence of asbestos.

Origin said importer Australian Mud Company Pty Ltd (AMC) first informed it that an imported product, NUTPLUG, contains asbestos.

AMC has withdrawn the product and claims it has formally notified relevant authorities.

NUTPLUG is allegedly made from ground walnut shells, and is used as a physical scouring agent to help clear the bottom-hole assembly of drill rigs.

The substance is not typically used in the actual production zone of an operation.

“We're now working through what does it actually mean,” Origin spokesperson Phil Craig told the ABC.

“We've just been informed that this product contains asbestos, so what we've done is immediately stood down the drill rigs and we have initiated a full investigation.

“Our first priority in that will be the health and safety of our employees.

“This is not a CSG-related issue - this is an issue with a product that is used as an additive as part of a process to prepare for CSG gas production,” he said, distancing the company from the chemical which is a known cause of cancer.

Origin says it has instigated its own independent investigation and informed relevant authorities and regulatory bodies.

Specialist support is being provided to those exposed to the drilling fluid additives, and a specialist hotline has been established as well.

Western Downs Mayor Ray Brown told media outlets that he was happy the company had stopped operations to find out the problem, but was careful not to blame them for the content of their fluid.

Councillor Brown says he is interested in “finding the source of where it's come from – [then] there's the issue of how did it get into the country in the first place, and what other industries have actually utilised it.”

“Have other industries been utilising this same fluid, whether it's in the water bore industries, anybody that's actually drilling in the earth, have they utilised the same fluid?”