The toll in an accident at an offshore oil platform operated by Brazil's state oil giant Petrobras climbed to five, media reported Thursday.
Two bodies were found in the machine room of the facility, Xinhua reported and according to the local Union of Espirito Santo Oil Workers (Sindipetro-ES), four people were still missing and 14 remained hospitalised.
The blast Wednesday, which originated in the oil rig's engine room, added to the woes of Brazil's largest government firm Petrobras, already reeling as a result of recent revelations that years of corruption at the top siphoned off millions of dollars from the firm.
The blast at the FPSO Cidade de Sao Mateus platform, located 120 km from the coast of the Espirito Santo state in southeastern Brazil, caused no oil spills, Petrobras said in a statement.
Workers were evacuated according to an emergency plan and the explosion was "brought under control" in less than an hour, the company said.
Half of the workers on the rig, which has stopped operating, were from other countries, and one of those critically injured was a Filipino, said Brazil's G1 news website.
A nine-member rescue team of firefighters was despatched to the rig late Wednesday to find the missing workers. Authorities suspect that the workers may be trapped in one of the rooms inside the platform.