( CNN ) -- The blown-out well at the heart of the worst oil spill in U.S. history has been cemented shut and is `` effectively dead , '' the federal government 's point man for the disaster said Sunday . `` 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 , '' former Coast Guard Adm. Thad Allen announced . President Barack Obama hailed the `` final termination '' of the ruptured well , but said the federal government will continue to do `` everything possible to make sure the Gulf Coast recovers fully from this disaster . '' The well erupted on April 20 and spewed an estimated 4.9 million barrels ( 206 million gallons ) of crude into the Gulf of Mexico before it was temporarily capped in July . Its owner , oil giant BP , began its final cementing operations to cap the well on Friday . The death of the well is a milestone that likely will draw only momentary celebration . As scientists debate how much oil remains below the surface , years of economic and environmental recovery in the region lie ahead . The federal government will press for answers on what went wrong April 20 and lawsuits -- including those brought by the families of the 11 workers who died in the Deepwater Horizon rig explosion -- will eventually make their way through the courts . BP stopped the oil July 15 , but pumping the bottom of the well with concrete -- the `` bottom kill '' -- was the final step in a five-month operation to ensure it will not leak . `` This spill began with a bang , ends with a whimper , and leaves a number of issues still screaming for attention , '' Rep. Edward J. Markey , D-Massachusetts , said Saturday . `` This may be the final nail in the coffin for BP 's well , but the investigations into this crime against the environment are continuing . Inquiries by Congress , the Obama administration 's independent panel , and others will progress until every inch of this environmental crime scene has been examined and a full autopsy has been performed on the spill 's effects , '' Markey 's statement said . The well operation is wrapping up as the company works to repair its image since the disaster . So far , BP has said it has paid $ 1.6 billion in claims and government payments . `` BP is doing everything we can to make this right . We continue to ... clean up the environment , and make sure that people are compensated for legitimate claims , '' its website says . Chief Executive Tony Hayward was moved to other duties partially because of a perceived lack of empathy for the victims of the spill . Hayward recently testified before a British parliamentary committee about the failure of the well 's blowout preventer , which is now in custody of the U.S. Justice Department and a focus of a criminal investigation into the disaster . BP shouldered some responsibility for the Gulf of Mexico oil disaster after an internal investigation of the spill , but assigned much of the blame to contractors Halliburton and Transocean . Faulty cementing , a misread pressure test and the improperly maintained blowout preventer all contributed to the April 20 explosion , BP 's nearly 200-page report on the disaster concluded . `` The team did not identify any single action or inaction that caused this accident , '' BP 's report states . `` Rather , a complex and interlinked series of mechanical failures , human judgments , engineering design , operational implementation and team interfaces came together to allow the initiation and escalation of the accident . Multiple companies , work teams and circumstances were involved over time . '' Both Halliburton and Transocean sharply disputed the findings , with Transocean calling them `` self-serving '' and Halliburton insisting that the problem lay with BP 's well design . Government scientists have estimated that at least 200 million gallons of oil leaked from BP 's damaged well , but 74 percent of it subsequently evaporated , broke up , or was skimmed or burned off . A team of researchers in the Gulf of Mexico say they found an oily layer as thick as two inches coating the sea floor in some places , and they believe it may be from the BP spill . `` I think what we 're seeing is oil that was on the surface , that has sedimented down to the bottom , '' said Samantha Joye of the University of Georgia . An analyst from the National Oceanic and Atmospheric Administration cautioned against jumping to conclusions before the samples are chemically analyzed .
NEW : Obama hails capping of well , says recovery efforts continue . BP well `` poses no continuing threat , '' says government 's point man . BP began final cementing operation to cap Gulf well on Friday . Environmental and economic recovery lie ahead .