3 victims who survived the disastrous explosion are now at the hospital. 2 were severely burnt.
A serious explosion at an Eni pipeline in Nigeria has caused the death of at least 12 people and injured three others.
The men were part of a maintenance crew, including security and environment officials, carrying out repairs on Thursday afternoon on the Tebidaba-Clough Creek line near the town of Azuzuama in the Niger delta's Bayelsa state.
On Friday morning, environmental activist Morris Alagoa, whose colleague had travelled to the scene, said that authorities were still combing the area for bodies.
"Four bodies were seen floating on the river today as the search continues," Alagoa said.
Iniro Wills, state commissioner for the ministry of the environment, said that the cause was still being investigated and one of his staff was still missing.
"Three victims rescued are now at the hospital. Two were severely burnt," Wills said.
Eni has a joint venture with Nigeria's state oil company.