The second blast survivor to give evidence in person over the disaster, Joseph Keith, said that he missed any sign that a blowout can happen, ahead of drilling mud started raining down on the rig floor just before the explosion.

The blowout triggered an explosion, which killed 11 people and led to the worst offshore oil spill in US history, reported The Associated Press.

Keith was giving his statement on the 11th day of a non-jury trial that commenced on 25 February and is expected to continue for several months.

During the trial, Keith said that rig workers were carrying out several other jobs such as operating a crane, making it difficult for him to observe the well for indications of a "kick" or unpredicted flow of fluids into the wellbore.

Keith testified that the rig normally stopped other activities, when workers were carrying out delicate job of shifting drilling mud with seawater.

During cross-examination by a lawyer for Transocean, Keith told that despite other activities, he could still able to execute his job "fully and capably" and could have alerted supervisors in case he had heard anything dangerous happening on the rig.

Keith was deployed on the rig to monitor well conditions and report any red flags to a BP rig supervisor and drillers employed by Transocean.

According to the mud logger, in the end BP was responsible of coordinating the operations and should have ceased other activities during the displacement process.