(Bloomberg) – Although Ecuadorians this month voted to shut a major oil field, local residents may be able to overturn the referendum and keep crude flowing, according to Oil and Mines Minister Fernando Santos.

The national vote ordered the shutdown of the 58,000 bpd field owned by national oil company Petroecuador, within a year. But area voters in the province of Orellana voted to keep the field operating and, according to Ecuador’s constitution, that local vote takes precedence, Santos said in an interview with television network Ecuavisa.

“Before we can touch a bolt of the infrastructure, we have to make a plan, the plan needs to be approved by the environment ministry and by the communities that live there, so we need that doubt to be resolved,” Santos said.

After a decade of legal battles, Ecuador’s Constitutional Court ruled in favor of holding the referendum, which went ahead on the same day as a snap election. Environmentalists call the oil production in the northeast of the Amazon rain forest Yasuni National Park a threat to the teeming wildlife of the area. Petroecuador says the shutdown will cost $1.2 billion a year and about $16 billion through the early 2040s.