Petroleo Brasileiro SA, Brazil’s state-controlled oil producer, said output growth slowed to the least since 2007 after regulators stepped up safety inspections in response to BP Plc.’s Gulf of Mexico oil spill.

Petrobras lost 12 million barrels of output after platform shutdowns, while growth was also curbed by delays in installing new equipment at the Campos basin, where Petrobras is struggling to slow declines at aging fields, Guilherme Estrella, Petrobras’ head of production, told reporters today in Rio de Janeiro.

Petrobras plunged the most in six months in Sao Paulo after quarterly profit missed estimates due to rising production costs and a weakening currency boosted import expenses. Petrobras was down 6.5 percent to 23.84 at 3:04 p.m. in Sao Paulo. The stock fell as much as 7.1 percent earlier, the most since Aug. 8.

Output rose 1.5 percent in 2011 to 2.6 million barrels a day of oil and natural gas on average, slower than its 7.7 percent target.

“It was a very difficult year with unplanned stoppages,” Chief Financial Officer Almir Barbassa also told reporters today. “Costs rose.”

BP’s 2010 Gulf of Mexico spill at the Macondo platform killed 11 people, sullied hundreds of miles of coastline and damaged fishing and tourism.