What happens to the oily mess and those who have to mess with it?

This is the last paragraph of an AP story about President Obama's visit to the Louisiana Coast today:

Early in the morning in advance of the president's arrival, hundreds of workers clad in white jumpsuits and rubber gloves hit the beaches to dig oily debris from the sand and haul it off. Workers refused to say who hired them, telling a reporter they were told to keep quiet or lose their jobs.

Can this be investigated further? What kinds of protections do these workers have other than jumpsuits and rubber gloves? Who is doing the work? Why are they being threatened? And where does the oily debris get hauled off to?