LIMA, Jan 29 — Peru’s environment ministry and Repsol SA yesterday increased the estimated size of a Pacific Ocean oil spill at a company refinery to over 10,000 barrels — significantly higher than an initial estimate of 6,000 barrels.

Repsol said it had calculated the oil spilled to be equivalent to 10,396 barrels, in response to a revised government estimate that put the number at 12,000 barrels.

The Spanish company has faced widespread backlash for the spill, which took place near capital Lima on January 15. Peruvian President Pedro Castillo has called it the biggest ecological disaster to affect the country in recent years.

Repsol added that 35 per cent of the oil spilled has already been recovered. Earlier in the day, a Peruvian judge barred four Repsol executives from leaving the country for 18 months as prosecutors investigate the cause of the oil spill.

The quartet include Repsol’s Peru chief, Jaime Fernandez-Cuesta. Lawyers for the executives did not appeal the decision and said they would cooperate with the investigation.

The spill took place at Repsol’s La Pampilla refinery, which the company has blamed on what it says were unusual waves triggered by a massive volcanic eruption in Tonga thousands of kilometres (miles) away.

A spokeswoman for La Pampilla has said the firm was not responsible for the spill and blamed the Peruvian Navy for not issuing a tsunami warning after the Tonga undersea explosion triggered Pacific Ocean-wide tsunami alerts.

La Pampilla is Peru’s largest refinery and accounts for 54 per cent of its refining capacity.

Prosecutor Tamara Gonzales said the executives did not comply with their "functional responsibilities” after the January 15 oil spill, which led to contamination of up to 140 km (90 miles) of coastline.

Repsol said in a statement that it will "continue to cooperate fully with any criminal investigation” related to the spill.

The crime of environmental damage carries a minimum prison sentence of no less than four years and no more than six, the prosecutor said.

Peru’s Agency for Environmental Assessment and Enforcement (OEFA) said on Thursday that Repsol did not comply with the deadline to identify damaged areas and began the process to impose a fine of up to US$4.8 million.

Repsol said in its most recent statement that it had some 2,000 people cleaning up the damage, with the support of 119 heavy machinery on land, 11 floating tanks and 52 boats. — Reuters