copyright HSE Image caption The Health and Safety Executive said the accident was "entirely preventable"

Andrew Jenkins' mother Linda said "justice hadn't been done".

"They are all going home to their family," she said. "I'll never see my son again."

Chevron said it "fully accepts" responsibility and recognised it "did not live up to" its own standards. It had "implemented changes" to avoid another disaster.

"Chevron continues to remember those individuals, families and colleagues affected by the incident," it said.

B&A Contracts also accepted responsibility and said if it could "turn the clock back" it would "in a heartbeat".

A spokesman said: "Denny, Andrew, Robert were dear friends to all of us, and Andrew was also family."

Safeguards had been implemented so "this can never happen again."accusations date to the postwar years, when the American right remained closely tied to the unvarnished anti-Semites of the '30s who railed against the "Jew Deal." Although Nixon never publicly voiced any of this old-fashioned bigotry, some of his political kinsmen did, and his strident anti-communism played with the Jew-hating fringe. (Extreme anti-communism always contained an anti-Semitic component: Radical, alien Jews, in their demonology, orchestrated the Communist conspiracy.) In Nixon's early campaigns, anti-Semitism was a latent theme.

When the Republicans nominated Nixon as their vice-presidential candidate in 1952, some opponents accused him of anti-Semitism. Nixon had Murray Chotiner, his (Jewish) campaign manager, secure the ADL's stamp of approval. Still, into the summer voters inundated campaign headquarters with letters asking about Nixon's feelings toward Jews. The candidate sometimes responded himself,