The head of the American Association of Professors has accused BP of trying to "buy" the best scientists and academics to help its defence against litigation after the Gulf of Mexico oil spill... BP says it has hired more than a dozen national and local scientists "with expertise in the resources of the Gulf of Mexico". The...contract offered to scientists by BP...says that scientists cannot publish the research they do for BP or speak about the data for at least three years, or until the government gives the final approval to the company's restoration plan for the whole of the Gulf... And...scientists must take instructions from lawyers...at BP... "Our ability to evaluate the disaster and write public policy and make decisions about it as a country can be impacted by the silence of the research scientists who are looking at conditions," [Cary Nelson of the Association] said. "It's hugely destructive..." In its statement, BP says it "does not place restrictions on academics speaking about scientific data"... But New Orleans environmental lawyer Joel Waltzer looked over the contract and said BP's statement did not match up.