On February 21, 2017, the journal Environmental Science & Technology published “Unconventional Oil and Gas Spills: Risks, Mitigation Priorities, and State Reporting Requirements,” an assessment of spill data from unconventional development operations in Colorado, New Mexico, North Dakota, and Pennsylvania. The study found that between 2-16% of unconventional wells report a spill each year. The study also found that 75% of wells that reported spills were within the first three years of production, and that 50% of all spills were related to storage and moving fluids via flowlines.
The blog Energy in Depth published a critique of the Duke study, noting that the Duke study included freshwater spills in its analysis. Energy in Depth also pointed to similar spill studies that found that 78% of all oil and gas related spills are contained on the well pad and never effect the environment.