[In the first week of the trial,] [t]he plaintiffs aim to show that pressure from senior management to hold down costs led to BP staff cutting corners on the Macondo well, causing the fatal explosion on the Deepwater Horizon rig and the subsequent leak of an estimated 4m barrels of oil into the waters of the gulf…BP agreed a settlement a year ago for tens of thousands of private sector plaintiffs, which is now expected to cost $8.5bn. Transocean, owner and operator of the Deepwater Horizon rig, in January agreed a $1.4bn settlement of the civil and criminal charges against it from the US government…A settlement is still possible, although…that becomes less likely with every passing week…By fighting in court, BP sets itself up for a year or more of uncertainty over the final cost of the spill, which it could resolve quickly by agreeing a settlement…Michael Underhill, the lead lawyer for the [Department of Justice]…[argued] that he intended to prove “wilful misconduct”, a higher standard than gross negligence...which in turn is higher than the ordinary negligence that BP has admitted…It is still entirely possible that Judge Barbier will…rule that there was wilful misconduct, or try to split the difference between that and BP’s admission of ordinary negligence with a finding of gross negligence. Either of those two outcomes would expose BP to Clean Water Act penalties of up to $17.6bn, and many billions in punitive damages for the states and private sector.