When a deadly explosion destroyed BP’s Deepwater Horizon drilling rig in the Gulf of Mexico, 134 million gallons of crude erupted into the sea over the next three months — and tens of thousands of ordinary people were hired to help clean up environmental devastation from the biggest offshore oil spill in U.S. history.

These workers were exposed to crude oil and the chemical dispersant Corexit while picking up tar balls along the shoreline, laying booms from fishing boats to soak up slicks and rescuing oil-covered birds.

Recognizing that some members of cleanup crews had likely become sick, BP agreed to a medical claims settlement two years after the 2010 disaster. Experts hailed it as “an extraordinary achievement” that would compensate workers fairly with little hassle.

But it hasn’t turned out that way.