Sean McCue and Keith Moncrieff were killed last month following a massive gas release while they were working on patched pipework in a leg of the Brent Bravo platform.
Only weeks before the tragedy oil unions had raised concerns about a backlog of maintenance on the rig.
But a report, released to workers on the Brent Bravo, firmly puts the blame on the two men, sparking angry scenes on the platform.
The report stated: "A hose clip on the drain line patch had been slackened on an unisolated line, apparently by one of the technicians, causing a significant leak from the pipe eventually resulting in a gas condensate, flashing to a heavier than air gas mixture in the leg.
"The rate of the release and quantity of gas was sufficient to rapidly overcome the two technicians who did not put on their emergency breathing apparatus."
Workmates of Mr. McCue, 22, of Kennoway in Fife, and Mr. Moncrieff, 45, of Invergowrie, Tayside, were called in for a meeting to discuss the report last week.
And almost immediately the men contacted Jake Molloy, of the highly-influential Offshore Industry Liaison Committee (OILC), to vent their anger. The one page report into the causes of the accident has also caused extra grief to the heartbroken families of the two men. However, Shell Expro denied they were apportioning blame to anyone.
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