Up to 16% of hydraulically fractured oil and gas wells spill liquids every year, according to new research from US scientists.
They found that there had been 6,600 releases from these fracked wells over a ten-year period in four states.
The biggest problems were reported in oil-rich North Dakota where 67% of the spills were recorded.
The largest spill recorded involved 100,000 litres of fluid with most related to storing and moving liquids.
The rapid growth in the extraction of oil and gas from unconventional sources in the US has had a massive impact on the production and consumption of energy over the past ten years.
BBC News –