Investors want oil giants to answer questions on their involvement in the environmentally damaging extraction of oil from tar sands Shareholders at BP and Shell will get the chance to vote at upcoming AGMs on whether to force oil giants to come clean on their Canadian tar sands involvement. Institutional investors including The Co-operative Asset Management and Rathbone Greenbank have co-signed a 'special resolution,' which would force the two companies to fully disclose and justify their involvement in Canadian tar sands.