Flaring of natural gas from oil wells appeared to cause an increase of around 11,000 hospital visits for respiratory reasons in North Dakota up to 60 miles away from oil drilling sites, according to new research.
The paper, recently published in the Journal of Public Economics, examines the environmental health costs of flaring in North Dakota between 2007 and 2015, the early days of the state's oil boom.
Researchers found evidence of a causal link between natural gas flaring and increases in hospital visits for respiratory health. They estimate that a 1% increase in flared natural gas increases the hospitalization rate by 0.73%
"The shale oil boom in North Dakota happened so quickly, and the area is so far from other oil drilling locations, they didn't have the infrastructure to process and clean the natural gas," said lead author Wesley Blundell, an assistant professor in Washington State University's School of Economic Sciences. "The data shows a rapid increase in flaring and a significant impact on human health with the increase in hospital visits."
The researchers looked at drilling and GPS data to map where flaring occurred, then reviewed hospitalization records, using anonymous hospital data of health codes for external respiratory reasons for the visits.
Blundell and coauthor Anatolii Kokoza also investigated whether the increase in hospital visits was caused by the flaring, or merely correlated with the issue. They eliminated many other potential causes, including the increase from more vehicles being driven because of the oil boom or from more people moving into the area.
The biggest surprise for Blundell wasn't that the flaring caused more people to require hospital visits. It was that people affected by the dirtier air aren't necessarily the ones benefiting from the oil production.
"We were shocked by how unfair wind is," Blundell said. "We found that 50% of the pollution from flaring went to areas that extracted less than 20% of the oil wealth. The people paying the health costs aren't necessarily the same people getting the benefits of drilling."