Chile's environmental regulator said it would seek to fine wood pulp producer Celulosa Arauco y Constitucion S.A. up to $29.5 million and could revoke the permit of one of its plants for contaminating a local river with a "green liquid" spill.
The SMA regulator pressed charges against Arauco, a unit of industrial conglomerate Empresas Copec, for 11 alleged environmental violations at its Planta Valdivia mill, some 460 miles (740 km) south of Santiago.
The most serious infringement claims that Planta Valdivia, which produces 550,000 tonnes of wood pulp annually, spilled a "green liquid" waste product on Jan. 17, 2014 that seeped into a nearby river.
"The SMA received a complaint of a mass death of fish in the Cruces River three days after said leak," the regulator added.
In the mid-2000s, Arauco gained media attention after hundreds of black-necked swans died at a nearby wetland sanctuary after operations started at its Valdivia plant.
Arauco has been fined at least 10 previous times by different regulatory bodies for infringing environmental regulations.
Arauco will have 10 days to present a compliance plan to the SMA or 15 days to present a legal defense.