NEW : BP doctor says up to 1,500 cleanup workers sickened . NEW : BP official admits that the oil spill is worse than first thought. Saturday is new target for linking surface vessel to ruptured well . Rough weather continues to be a challenge in cleanup .
NEW : BP doctor says up to 1,500 cleanup workers sickened . NEW : Oral arguments on drilling ban begin Thursday . Saturday is new target for linking surface vessel to ruptured well . Rough weather continues to be a challenge in cleanup .