Brazilian prosecutors say they will bring criminal charges against 17 executives from the US oil company Chevron and drilling contractor Transocean after a new leak of crude.
The executives have been barred from leaving the country until the investigation concludes.
Chevron halted production in Brazil after the new oil leak was found on the seabed off Brazil earlier this week.
The seepage is near a well where there was a major oil spill last November.
A Chevron spokeswoman said the company had no comment on the latest legal moves because it had not been notified of the decision.
The oil company is already facing a multi-billion-dollar lawsuit over November's spill.
Federal prosecutors' spokesman Marcelo del Negri told AP news agency that prosecutors would file charges including "environmental crimes" in a federal court next week.
The nationalities of the executives are reported to be five from the US, five Brazilians, three Australians, two French nationals, a Canadian and a Briton.
Chevron confirmed on Thursday that there was a "small new oil seepage" and that it was working to collect the crude.
In November up to 3,000 barrels of oil spilled from the well in the Frade field, which is around 370km (240 miles) off Rio de Janeiro.
Brazil's oil regulator, ANP, said the new leak appeared to be coming from cracks in the ocean floor close to the well, rather than from the well itself.
The Frade field is the largest foreign-run oil field in Brazil, producing about 60,000 barrels of crude oil a day.