BP Plc removed a containment cap from its stricken Gulf of Mexico oil well on Saturday in the first step toward installing a bigger cap to contain all the crude gushing into the sea and fouling the coast.

The maneuver released a torrent of oil that will spew unrestrained into the Gulf for four to seven days — the time BP says it will take to put in place a bigger cap and seal. Officials say the new cap would capture all the oil leaking from the well and funnel it 1 mile upward to vessels on the water’s surface.

The new solution, 82 days into the worst oil spill in U.S. history, would not allow crude to billow out the bottom and the top, as the current cap does, said Kent Wells, senior vice president of exploration and production for BP.

“The difference is one completely seals and the other didn’t,” Wells said.