Esso and one of its contractors, Austin & McLean, have pleaded guilty to health and safety breaches following the death of an employee at Fawley oil refinery five years ago.
Juan Romero was crushed to death by a giant fuel pipe at the Southampton facility in August 2008.
The Crown Prosecution Service had previously claimed that the pipe came free when a corroded connector bolt failed.
Esso’s defence barrister, Richard Latham QC, told Winchester Crown Court that he had been instructed to formally enter a guilty plea to one of five charges facing the company.
Mr Latham said that the company’s board admitted guilt over a charge of failing to ensure that lifting equipment was maintained and in good working order.
He went on to say Esso would contest other charges surrounding an alleged failure to ensure the health, safety and welfare of employees at the Fawley premises.
Both companies are expected to be sentenced later this year in December.