50% of Dart’s 7-year-old wells in Dalby, Queensland were found to be leaking by the Queensland government. Tests showed high levels of benzene, toluene, ethylene and xylene (BTEX) in ground water close to the wells. These bores were drilled in 2004/5 when Dart was part of Arrow Energy. They were later allocated to Arrow when the companies split in 2010.
BTEX chemicals are hazardous (see p5&6 of link) in the short term causing skin irritation as well as central nervous system and respiratory problems. Prolonged exposure can impact the kidneys, liver and blood system. Long-term exposure to high levels of benzene in the air can lead to leukemia and cancers of the blood.
Production of BTEX is an unavoidable risk in CBM drilling since the compounds are found naturally in coal seams. And the fact that BTEX has been found in ground water belies industry claims that there is no link between their activities and pollution of groundwater.
A crucial problem is a basic fact: gas wells leak. Gas service company Schlumberger found 60% of gas wells leaking after 30 years. In 2000, eight thousand gas leaks were found in the Gulf of Mexico by the US Mineral Management Services department (p2 of the linked pdf).
Last year, Archer, a well service company, estimated worldwide that 19% of operating wells were shut down due to integrity issues (see p4 of the linked pdf).
See footage below of the Australian CBM gas field where, in 2011, the Queensland Mines Department – found 26 out of 56 Coal Bed Methane wells leaking at the Tara gas field – 44%
As wells leak, so do the associated toxic chemicals. And since these chemicals are increasingly finding their way to the surface a central lie by the industry is illustrated: CBM is safe and non-polluting.
It is not.