Spanish energy firm Repsol said the cleanup operation for a major oil spill on the coast near Peru's capital Lima would take until the end of February, in an environmental incident declared a 'catastrophe' by the government.
Dead seals, fish and birds have washed up on the shore covered in oil, while fishing activities in the area have been suspended, the government has said.
Almost a million litres of crude spilled into the sea on Saturday when a tanker was hit by waves while offloading at La Pampilla refinery in Ventanilla, 30 kilometres north of Lima.
Its owner, Spanish oil company Repsol, attributed the accident to the swell caused by the volcanic eruption in Tonga, thousands of miles away.
Workers clean oil from Cavero Beach after a spill in Ventanilla, Peru. Source: AAP
"Oil reaches the beach during high tide at night... and deposits the oil on the shore," Martin Martinez of the NGO AMAAC Peru, supervising the cleanup, told AFP.
"We take advantage to remove it from the sea, that and the saturated sand," he said.
Repsol said it had enlisted fishermen to help clear-up the oil.
"I used to collect crustaceans, but now, when I walk to the shore, they are dead," fisherman Walter de la Cruz told Reuters.
"Fishermen used to go sell the seafood that we collect. But now everything smells like death."
The Pacific Ocean off Peru is a significant source of marine life and seafood for Peruvians, who cherish dishes such as ceviche.
Spanish oil company Repsol has attributed the oil spill to the swell caused by the volcanic eruption in Tonga. Source: AAP
The spill has dealt a blow to tourism at Peru's popular resort of Ancon, and to businesses who make most of their money in the summer season.
"There were many people until Sunday; the stain arrived on Monday, and since then, no one is swimming anymore," said 48-year-old Richard Gutierrez, who has a food and soda stand on Miramar beach.
"We cannot sell anything, there are no vacationers, there is no one" apart from about 100 cleanup workers - soldiers, Repsol hired hands and volunteers - removing the polluted sand with spades to be taken to a toxic waste treatment facility.
Repsol said it deployed about 840 people to help with cleaning tasks. Repsol's La Pampilla accounts for 54 per cent of Peru's refining capacity.
Peru's government has declared the spill of some 6,000 barrels of oil an "ecological disaster" and has demanded compensation from Repsol.
The company denies responsibility, saying maritime authorities had issued no warning of freak waves after the Tonga eruption.
The task, which began Tuesday, is an arduous one.
The workers deposit the polluted sand onto blue tarps, which are dragged to a pile further inland, awaiting removal to another site.
Work begins at 8:00 am and finishes at 6:00 pm, with a 30-minute break for lunch.
No one knows how long it will take to clean up the affected stretch of coastline, but in Miramar, it is estimated it will last at least two weeks.
The environment ministry said 174 hectares - equivalent to 270 football fields - of coast were affected, and some 118 hectares at sea.
Marine currents have dispersed the oil all the way to the coast of Chancay district, more than 40 kilometers from where the spill occurred.
The health ministry has identified 21 affected beaches and warned bathers to stay away.
The spill has also affected hundreds of artisanal fishermen who operate on the central Peruvian coast.
They rely on catches of sole, lorna drum and Peruvian grunt - fish commonly used in the local delicacy ceviche, a marinated raw fish dish Peru is famous for.
Additional reporting: Reuters