London , England ( CNN ) -- Greenpeace protesters briefly shut down BP stations across London on Tuesday , after the oil company announced its second-quarter results , BP and Greenpeace said . Greenpeace said it had shut down 46 stations , but BP said the number was 40 . The protesters dropped off a letter at each station in the morning and , on their way out , pulled a safety switch that cut off power to the station , BP and Greenpeace said . They also covered BP signs with posters reading , `` Closed : Moving beyond petroleum , '' a take on BP 's slogan . Most of the stations were operating again by the afternoon and the rest were expected to reopen by the evening , BP said . One of the stations supplied ambulances , BP said . The affected stations were a mix of company-owned and dealer-owned , BP said . Greenpeace said it simply targeted stations that sell BP gas . Asked about targeting stations that may be owned by individuals or businesses other than BP , Greenpeace spokeswoman Beth Herzfeld said they `` do n't want to make anybody suffer . '' `` We 're sorry for any problems that are caused , but the petrol that are sold in these businesses are BP , '' she told CNN . `` BP is determined to chase the last drops of oil , whatever the cost to the natural environment and people 's health . '' Herzfeld said Greenpeace was aware that one of the targeted stations supplies ambulances , but she said the group was directing emergency vehicles to other non-BP stations nearby . `` We 're very careful and very keen to make sure that nobody 's safety is compromised , '' she said . The protests came after BP unveiled a massive $ 17.15 billion loss in the second quarter due to costs stemming from the Gulf of Mexico oil disaster . The oil company said it took a pre-tax charge of $ 32.2 billion in the quarter to cover costs relating to the oil spill . It also announced its embattled Chief Executive Officer Tony Hayward will step down on October 1 , following fierce criticism of the way he has handled the disaster . CNN 's Kendra Petersen and Caroline Paterson contributed to this report .
Greenpeace protesters shut down BP stations in London . At least 40 stations were affected . Protestors covered BP signs with posters . Most of the stations are running again .