The 14,000 inactive oil and gas wells in the US Gulf of Mexico region can still leak and harm marine ecosystems in the process. However, the cost of securing them could reach $30bn (£23.7bn), according to researchers at the University of California.
The team collected data from the US Bureau of Safety and Environmental Enforcement on the 82,000 wells drilled in the Gulf of Mexico. Although the majority of the wells have been secured, the researchers found evidence that more than 14,000 wells are still unplugged, despite having been inactive for at least five years - a point beyond which they are unlikely to restart production.
Operators are legally required to plug wells once they are taken out of production, which usually involves a cement cap covered with sediment.
"The wells aren't supposed to just be leaking into the environment if they're not actively producing, but sometimes they do," said Mark Agerton, lead author of the study published in the...