A leaking well which spewed millions of barrels of oil into the Gulf of Mexico has finally been sealed, US officials said.
Oil giant BP killed the leak by pumping cement into the bottom, ending a five-month battle that started when one of its oil rigs exploded.
The Deepwater Horizon rig blew up on 20 April, killing 11 workers.
A cap sealed the flow of oil three months later.
But the ruptured well could not be declared dead until a relief well was drilled, and a pressure test confirmed that the plug was holding.
Coast Guard Admiral Thad Allen, the federal official who oversaw the disaster, said the well was “effectively dead”.
“Additional regulatory steps will be undertaken but we can now state definitively that the Macondo Well poses no continuing threat to the Gulf of Mexico,” he said.
It is estimated that 206M gallons of oil has spewed into the Gulf since the disaster.
It led to the resignation of BP chief executive Tony Hayward and a moratorium on deepwater offshore drilling.
BP accepted it was partly at fault for the disaster in an internal report, admitting its workers misinterpreted a key pressure test of the well.
But it also pointed the finger at its partners on the rig.
The firm’s stock price has started to recover but took a massive nosedive after the explosion. The clean up has cost it US$8bn (5.1 billion), with another US$20bn (£12.8bn) set aside for a compensation fund.
Mr Hayward, who is due to step down next month, said: “This is a significant milestone in the response to the Deepwater Horizon tragedy and is the final step in a complex and unprecedented subsea operation – finally confirming that this well no longer presents a threat to the Gulf of Mexico.
“However, there is still more to be done. BP’s commitment to complete our work and restore the damage done to the Gulf of Mexico, the Gulf coast and the livelihoods of the people across the region remains unchanged.”
BP said it will now complete the abandonment of the well.