Firms involved in rig 's sinking made `` very major mistakes , '' David Mattingly says . `` And what 's also clear is they 're passionate about protecting their home . '' Coast Guard scrambles to clean up second patch of oil known to reach shore . Containment dome arrives on site above source of massive oil spill . Officials hope dome will capture oil leaking about 40 miles beneath the Gulf of Mexico 's of Houston .
Firms involved in rig 's sinking made `` very major mistakes , '' David Mattingly says . Coast Guard scrambles to clean up second patch of oil known to reach shore . Containment dome arrives on site above source of massive oil spill . Officials hope dome will capture oil leaking about 40 miles beneath the Gulf of Mexico 's of Houston .