The walkout over profit-sharing and safety issues may force the company to cut output from about 40 percent of the Campos Basin, Brazil's main producing region, as well as fields in Brazil's northeast and Amazon regions, said Marluzio Ferreira, spokesman for the national oil workers federation. Work was also disrupted at 11 refineries, he said.
The union says Petrobras has refused requests to improve safety measures, and that 165 employees have been killed since 2002.
The union also says the company has sought to cut revenue and profit sharing. Petrobras, which is adding workers, is aiming to reduce costs as oil prices fall and it embarks on a $174.4 billion five-year investment plan.
Petrobras said in a statement on its Web site that all its units were operating normally during the strike.
Author: Ksenia Kochneva