Agence France-Presse: BP was dealt a setback Saturday to capping a massive oil spill in the Gulf of Mexico after a containment dome encountered flammable hydrate formations as it was lowered onto the leak site. The gas hydrates, similar to ice crystals, formed on the inside of the 100-ton (90-tonne) chamber as it neared the seabed nearly a mile (1,500 meters below the surface, making it too buoyant and clogging it up, BP chief operating officer Doug Suttles told reporters. Workers have moved the …