Why can't the Obama adminstration order BP to stop using dispersant?

Federal law allows agencies to suspend or bar from government contracts companies that engage in fraudulent, reckless or criminal conduct. The sanctions can be applied to a single facility or an entire corporation. Government agencies have the power to forbid a company to collect any benefit from the federal government in the forms of contracts, land leases, drilling rights, or loans.

The most serious, sweeping kind of suspension is called "discretionary debarment" and it is applied to an entire company. If this were imposed on BP, it would cancel not only the company's contracts to sell fuel to the military but prohibit BP from leasing or renewing drilling leases on federal land. In the worst cast, it could also lead to the cancellation of BP's existing federal leases, worth billions of dollars.

Present and former officials said the crucial question in deciding whether to impose such a sanction is assessing the offending company's culture and approach: Do its executives display an attitude of non-compliance? The law is not intended to punish actions by rogue employees and is focused on making contractor relationships work to the benefit of the government. In its negotiations with EPA officials before the Gulf spill, BP had been insisting that it had made far-reaching changes in its approach to safety and maintenance, and that environmental officials could trust its promises that it would commit no further violations of the law.