A shutdown happened when an underwater robot apparently hit a containment cap atop failed blowout preventer equipment that channels oil to adrill ship a mile (1.6 km) up on the water's surface.
BP Plc said on Thursday that its oil-capture systems at the leak in the Gulf of Mexico collected or burned off 16,830 barrels of oil on Wednesday, a 38% decrease from its record rate of 27,100 on Tuesday.
The decrease reflects a 10-hour shutdown of one of the systems on Wednesday.
The shutdown happened when an underwater robot apparently hit a containment cap atop failed blowout preventer equipment that channels oil to a drill ship a mile (1.6 km) up on the water's surface, according to the US Coast Guard.
BP removed the cap Wednesday morning to assess its condition, then replaced it about 10 hours later. In the interim, crude gushed unchecked from that leak site.
In the hours before and after the shutdown, that system collected 8,300 barrels of oil, BP said.
A second system that siphons more oil from a hose connected to the blowout preventer to a service rig operated normally. That system burned off 8,530 barrels of oil on Wednesday, BP said.
A team of US scientists estimates the leak is spewing up to 60,000 barrels a day.