Nigeria has placed an embargo on government contracts with a subsidiary of US oil services firm Halliburton.
President Obasanjo backs the embargo against Halliburton
It said it was taking action against Halliburton Energy Services Nigeria (HESN) as a result of negligence in security and safety matters.
In 2002, radiation emitting devices used by the firm to make measurements in oil wells were reported missing in Nigeria's oil-rich Delta region.
The equipment was eventually traced to a location in Germany.
At the time, Halliburton was accused of doing too little to help the Nigerian authorities recover the equipment.
"The federal government has decided to place an embargo on the patronage of Halliburton Energy Services Nigeria Limited arising from its negligent conduct which led to the loss of two ionizing radioactive sources from Nigeria in 2002," a government statement said.
"Additionally, the company, among other infractions, has refused to cooperate with government authorities in ensuring the return of the sources to Nigeria and the ultimate resolution of the issue," it said.
All contracts between the company and any Nigerian ministry or government agency would stop until further notice, the statement said, adding the ban had been approved by Nigerian President Olusegun Obasanjo.
Halliburton, which was headed by US Vice-President Dick Cheney until he took office in 2001, operates in both Nigeria's oil and natural gas sectors.