Last April, a volcanic eruption in Iceland sent a cloud of ash billowing towards Europe. That ash was potentially hazardous for aircraft, and authorities decided to ground all flights — inconveniencing tens of thousands of travelers — rather than risk an accident.
Although images of dead birds and blackened marshes in the Gulf of Mexico are gone, many scientists say it's too early to declare a recovery. They suspect there could be hidden damage to the Gulf's marine life and marshes.
A year ago Wednesday, the Deepwater Horizon oil rig in the Gulf of Mexico exploded, killing 11 workers and setting off a massive spill that sent millions of barrels of oil into the Gulf.The disaster focused a spotlight on government oversight of offshore drilling, which was generally found to be ina