* Shell calls for tougher risk assessments, what if plans
* Calls for investigation into reasons behind blast
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By Tom Bergin
LONDON, Oct 14 (Reuters) - Royal Dutch Shell Plcurged the U.S. to adopt the tougher drilling rules applied in the North Sea, which it said could have helped prevent the mistakes that contributed to BP's Gulf of Mexico oil spill.
Shell Chief Financial Officer Simon Henry said on Thursday the U.S. should forced everyone drilling a well to prepare a "safety case" -- plans that examine all potential risks and defines who is responsible for all risk management tasks.
"What we would like to see is that the regulations, as they evolve, match more clearly the European approach, which is always to identify all the hazards," he told Reuters Insider TV in an interview.
U.S. lawmakers have criticised regulations on exploration in the Gulf of Mexico for not requiring oil companies to rigorously assess the risks of drilling.
BP's own investigation into the disaster said it was not clear whether BP staff or its drilling contractor were responsible for signing off on key safety tests for the rig, which exploded in April, causing the worst-ever oil spill in the United States.
Shell prepares safety cases for all its wells all over the world because it represents best practice, Henry said.
MOTIVATIONS MUST BE PROBED
A BP spokesman said the company did not prepare safety cases for its Gulf of Mexico wells but denied this meant it applied lower safety standards in the United States than in the North Sea.
Many oil executives have said that UK and Norwegian safety requirements are tougher than U.S. regulations.
BP and its rivals, including Shell, have been locked in a war of words over the last several months about whether the well blowout was due to inadequate industry practices or BP's own shortcomings.
U.S. lawmakers have alleged that BP's culture encouraged staff to place costs before safety. However, BP's probe into the rig blast focused on the chain of events that led to the blast and not any of the factors that may have affected the decisionmaking leading up the it.
In an apparent criticism of BP's probe, Shell CFO Henry said the motivations behind the decisions that led to the blast, needed to be investigated.
"Why was such an environment created that enabled the events to happen?" he said.
Henry also said Shell was not looking to sell or close any more refineries in the U.S. It has divested several facilities in recent years. (Editing by Karen Foster)