Kent Robertson, a spokesman for Chevron, said there was no evidence that any death or illness had been caused by its operations. He said that when Texaco left Ecuador in the early 1990s, it arranged for 40 per cent of the pits to be decontaminated and signed a contract with the Ecuadorian government that Petroecuador would deal with the rest. Any sign of contamination now was Petroecuador's work, he said.