Leading article: It's not just BP we need answers from

As America grapples with what may be the worst oil spillage in history, eclipsing the Exxon Valdez disaster in 1989, two questions demand answers: first, why was no remote control shut-off device installed at Deepwater Horizon? And second, is this disaster in the Gulf of Mexico connected to lobbying on the part of BP against the imposition of tighter safety controls for off-shore drilling? BP needs to provide convincing answers to both questions if it is not to find itself on the end of lawsuits that could wreak havoc with both its reputation and its finances.

The company is not popular in Washington as it is, partly because of a series of accidents in recent years, most notably in Texas in 1995 when a refinery exploded, killing 15 people, and in 2006, when a pipeline leaked in Alaska. The big oil companies in general, meanwhile, have a less sympathetic president in Barack Obama than they did in his predecessor, George W Bush. Mr Obama has said that he intends to hold BP responsible for most of the clean-up bill. The President may adopt a harsher tone once the oil reaches the shore, potentially affecting the jobs of thousands of people living in coastal communities as well as killing countless millions of sea birds, turtles and fish.

The word "spillage" barely conveys the apocalyptic nature and scale of what is going on. Most worryingly, in the absence of a remote control shut-off device, no one has satisfactorily explained how the volcanic flow of hot oil into the Gulf of Mexico from some 5,000ft beneath the waves can be stopped. BP seems literally out of its depth. The booms it has placed in the Gulf to contain the slick and stop the oil from reaching the coast have not worked, possibly because they were placed too far out to sea, where high waves have rolled over them. It could be weeks or even months before a cap is installed or the flow diverted, by which time the spillage will have far exceeded the eleven million gallons that Exxon Valdez released off Alaska. It will be miraculous if the waters of the Gulf, from which the United States extracts 40 per cent of its seafood, do not suffer long-term devastation.

While BP faces immediate questions, alongside huge bills, the buck must not be allowed to stop with the company. President Obama has announced that he is halting new off-shore drilling projects unless rigs have safeguards to prevent similar disasters from occurring. But Americans will surely want to know why those safeguards were not there to start with, given Deepwater Horizon's highly sensitive location, only a few dozen miles from as environmentally a precious area as the Mississippi River Delta. Oil companies will always lobby aggressively for the right to explore as widely as possible and under as few conditions as they can get away with. It is for politicians to reconcile those ambitions with public and environmental safety. The inquiry into who nodded this rig through and why must go all the way from Louisiana, Alabama and Mississippi to Washington itself.

With oil still surging into the Gulf, in ever increasing quantities, it may sound premature to talk of lessons that need to be learned in future. But we must assume that the flow will be stopped somehow and at some point, after which the public in America and elsewhere hopefully will start drawing some conclusions about where the relentless hunt for cheap oil is leading. It should be transparent to everyone by now that the addiction of all our economies to oil is what is ultimately driving the demand for exploration into ever deeper and riskier environments.

Of course, improved safety standards for rigs are crucial, and must be insisted on and adhered to – but if their introduction is not accompanied by a more consistent drive to reduce our dependence on oil, they alone will not be enough to save us from similar disasters.