RIO DE JANEIRO, Brazil - Hundreds of workers dug runoff channels and strung barriers across a river in southern Brazil on Tuesday in a race to contain the country's worst oil spill in 25 years.
By afternoon, an oily black stain had moved about 25 miles downstream from the Getulio Vargas oil refinery in Araucaria, where a burst pipe spewed more than 1 million gallons of crude oil into a tributary of the Iguacu River on Sunday.
Dead fish, birds and mammals coated in oil were washing up on the Iguacu's banks, environmental officials said. Egrets and capybaras - the world's largest rodent - were particularly hard hit. Riverside residents were instructed to stop irrigating crops and cooking with the water.
Environmentalists said their goal was to keep the spill from reaching Uniao da Vitoria, a city of 70,000 people about 125 miles below the slow-moving slick. The city depends on the Iguacu for drinking water.
Jose Antonio Andreguetto, president of Parana State's Environmental Protection Agency, said the spill already has affected more than 10,000 riverside residents. And while the water quality could recover within two or three days, environmentalists said the oil-coated river bed and banks will take longer to bounce back.
''Plants and animals are significantly affected,'' said Andreguetto. ''The rehabilitation of the ecosystem will take a long time and will be very difficult.''
More than 400 oil workers, firefighters, civil defense workers and environmentalists worked through the night Monday in subfreezing temperatures to check the spill.
On Tuesday, three barriers were set up across the 150-foot-wide river. Bulldozers and backhoes dug runoff channels to collect the contaminated water and oil workers with hoses sucked it off the surface.
If the barriers fail to halt the oil, a dam and a reservoir immediately downstream after the city will collect whatever slips by, Andreguetto said.
The refinery where the huge leak originated is owned by federal oil giant Petrobras. The Parana State Environmental Protection Agency has said it will fine Petrobras $28 million.
''Petrobras must answer for this,'' Environment Minister Jose Sarney Filho said. ''This is absolute negligence.''
Petrobras President Henri Phillipe Reichstul said the company accepts full responsibility for the accident and that ''unlimited'' resources will be used to repair the environmental damage.
In January, an underwater oil pipe at the company's Reduc refinery near Rio broke and spewed at least 340,000 gallons of crude into Guanabara Bay and through protected mangrove swamps. Ecologists say the area will need at least a decade to recover.
Brazil's worst oil disaster was in 1975, when an oil tanker from Iraq dumped nearly 8 million gallons of crude into Guanabara Bay. The oil washed up on Rio's famous beaches, which were closed for nearly three weeks.