WASHINGTON — BP expanded its effort to recover oil at its runaway Deepwater Horizon well on Wednesday, activating a system it hopes will raise the amount of crude being collected to 20,000 to 28,000 barrels a day.

BP said in a statement on its website that oil began flowing to the Q4000 drilling platform from the well's failed blowout preventer at 9:50 p.m. Central Time Tuesday and reached the Q4000 at 1 a.m., where it was burned.

BP later said that 1,240 barrels of oil had been burned as of noon Wednesday.

Officials are counting on the Q4000 to receive 5,000 to 10,000 barrels a day once it is fully operational, while the primary colllection vessel at the site, the drill ship Discoverer Enteprise, has capacity to process 15,000 to 18,000 barrels daily.

The Discoverer Enteprise collected only 10,440 barrels Tuesday after a fire set by a lightning strike forced the rig to shut down for nearly five hours.

The decision to burn as much as 10,000 barrels of day of crude has sparked concerns that workers and residents could be exposed to toxic fumes. Such a system has never been used before to dispose of so much oil in a cleanup effort.

The Q4000 has served key roles in two other efforts to stop the leak. It was the platform that lowered a 78-ton containment dome into the water that BP had hoped would corral some of the escaping crude, but was abandoned after ice-like crystals grew inside it. The Q4000 also was the platform from which BP pumped drilling lubricant into the well's blowout preventer in the failed "top kill" effort.

BP had to reconfigure the Q4000 to add equipment to burn crude oil for its current recovery role. The crude burner mixes the oil with compressed air before it is ignited.