Chile's state-owned Codelco, the world's largest copper producer, said on Wednesday it stopped maintenance at its Ventanas smelter and refinery after authorities declared an environmental emergency in the area earlier this week.
Chile's environmental regulator on Tuesday ordered interim measures against the mining company and power company AES Chile after dozens of people showed signs of being poisoned by sulfur dioxide emissions in the towns of Quintelo and Puchuncawe in central Chile.
Codelco's measures include installing a new temperature sensor to determine heat inversion and other measures of ventilation quality.
"To ensure proper implementation of the measures, the industrial operation will maintain the voluntary shutdown that has been discontinued since Monday and move forward with scheduled maintenance," Codelco said in a statement.
"The company hopes to clarify responsibility following the poisoning incidents that have affected residents in the area in recent days."
Codelco explained that sulphur dioxide concentration parameters recorded by its air quality station were normal at the time of the incident on June 6, and the smelter has been shut down ever since.
AES Chile said it would also comply with the regulator's measures and denied responsibility for the environmental incident.
Environmentalists have long called Quintero and its surrounding area "sacrifice zones" in response to successive pollution episodes that have led to public health emergencies.
The town is home to many industrial activities, including the state-owned oil company ENAP and the chemical industry.
