The civil lawsuit seeking $3 billion for environmental damage and $1.5 billion for damages to locals and consumers was filed by Peru’s consumer protection agency Indecopi.

Repsol has said the lawsuit is meritless, the sum demanded is arbitrary, and that the spill was not its fault.

The proceedings, however, add to Repsol’s legal troubles. The company is also facing a criminal investigation over the spill and prosecutors have barred four top executives from leaving the country for 18 months.

Peru has called the incident the country’s worst environmental disaster in recent memory.

Repsol said in May that cleanup of the spill would cost it $150 million.

Indecopi has alleged that environmental damage is continuing to affect beaches and fishermen.

“We are looking to get compensation for the affected population…that lives within 150 kilometers of contaminated coast,” said Julian Palacin, the head of Indecopi, in a statement.

The spill took place in January at Repsol’s La Pampilla refinery, located an hour north of capital Lima. Repsol initially blamed the incident on anomalous waves triggered by an underwater volcanic eruption near the island of Tonga, but has since shifted blame to an oil tanker.

Others named in the suit include insurer Mapfre Global Risks and Italian firm Fratelli D’Amico Armatori S.P.A, which owns the crude tanker from which the oil spilled.

(Reporting by Marco Aquino and Marcelo Rochabrun; Editing by Jamie Freed)