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expert reaction to study of air pollution around oil and gas wells in the US

Research published in the journal Environmental Health has found the levels of some chemicals in the air around oil and gas drilling sites in the US to be higher than allowed by law.


Prof Paul Monks, Professor of Atmospheric Chemistry and Earth Observation Science at the University of Leicester, said:

“The work suggests significant emissions of a wide range of volatile compounds from shale gas extraction. Many of these compounds are of concerns to air quality and therefore health, but the situation in the US is not directly transferable to the UK owing to the different legislative regulation regime and the different nature of UK shales.”

“Recent UK work looking at Lancashire shales has shown significantly lower concentrations of these air toxins such as benzene.”


Dr Rob Westaway, Senior Research Fellow at the University of Glasgow, said:

“One of the key difficulties faced by the incipient UK shale gas industry is that it will be required to operate to far higher environmental standards than currently prevail for shale gas projects in North America, as regards a whole host of environmental issues. For example, DECC has determined that (except as a safety precaution in emergencies) all UK shale gas wells will have to capture and process or treat all gases released rather than venting or flaring them as is customary in the USA and Canada. Furthermore, at all UK sites the water required for fracking will have to be stored, between fracking operations, in enclosed tanks rather than in open ‘lagoons’. In addition, it is accepted that it is less polluting for onshore drill sites to use electrically powered rather than diesel powered equipment, and so shale gas developments in the UK will be sited wherever possible in localities where they can draw electrical power from the national grid.

“This paper describes a range of problems that result from lax regulation, such as flaring of methane or venting of hydrogen sulphide from shale gas boreholes, or evaporation of other chemicals from water that has already been used for ‘fracking’ and is being stored temporarily, pending reuse, in open ‘lagoons’. In the UK all these potential forms of routine pollution will be forbidden. Methane will have to be collected, not flared; any hydrogen sulphide in the gas stream will have to be removed on site by chemical treatment, not vented into the atmosphere; ‘flowback fluid’ from fracking will have to be stored in closed tanks between ‘fracking’ operations, and so on.

“Furthermore, emission standards for diesel powered drilling equipment within the EU are now very tight; all new equipment is required to comply with the EU ‘Stage IIIB’ regulations to minimise emissions of nitrogen oxides (NOx). So if diesel powered equipment does have to be used for any particular shale gas project, the emissions will be much less than are calculated in this paper, which utilises data from past projects where much less stringent emission regulations were in place. Although old drilling equipment does not have to comply with the new EU emissions regulations, it would be straightforward to make such compliance a condition of planning permission for any UK shale gas project.

“A number of studies have shown that the combination of environmental measures that will be required in the UK will reduce the pollution per shale gas well dramatically, to levels that are negligible, compared with U.S. conditions. Given the tight regulatory framework that will be required, the main environmental impact of UK shale gas will be the carbon dioxide emissions from its combustion, which will be no different from those experienced by burning equivalent amounts of conventional ‘natural gas’. Since much of the UK’s current natural gas supply is imported, and requires transport over large distances, the overall lifecycle impact of UK shale gas may well be less than that for imported ‘natural gas’, as there will be no need for the emissions from burning the fuel to power gas-carrying tankers.

“Paul Younger and I have recently submitted for publication a commentary on a paper by another UK group, which estimates the pollution impact of UK shale gas by assuming that the lax regulations that prevail in the USA will apply. Since the lax regulation in the USA will not apply in the UK, any discussion of their potential consequences in terms of pollution is completely irrelevant. However, it is evident that this point is not widely appreciated; we hope this note will help to clarify the situation.”


Prof Andrew Aplin, Professor of Unconventional Petroleum at Durham University, said:

“Whilst pollutants such as benzene and toluene occur in the atmosphere of every urban environment, this study shows that very high concentrations of hydrocarbons and hydrogen sulphide were found in the very local vicinity of some specific oil and gas operations in the US.

“Poor industrial practice and insufficient regulation can of course result in locally elevated concentrations of atmospheric pollutants in many urban and industrial situations – this is why the UK passed the Clean Air Act in 1956. Industrial emissions are tightly regulated in the UK and these regulations currently apply to those who have been producing conventional oil and gas in the UK for many years. The same rules will apply to any future producers of shale gas and it is incumbent upon us to make sure that the same rules are followed and enforced.”


‘Air concentrations of volatile compounds near oil and gas production: A community-based exploratory study’ by Gregg P. Macey et al. published in Environmental Health on Thursday 30 October 2014.


Declared interests

Andrew Aplin receives funding from the petroleum industry for his group’s research on the geology of unconventional resources.

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