Radiation expert Andrew Karam, who covered the disaster for Popular Mechanics in 2011 and later traveled to study the site, explains everything you need to know about Fukushima’s legacy and danger five years later.

• See also via Newsweek – “The robots sent in to find highly radioactive fuel at Fukushima’s nuclear reactors have “died”: a subterranean “ice wall” around the crippled plant meant to stop groundwater from becoming contaminated has yet to be finished. And authorities still don’t how to dispose of highly radioactive water stored in an ever mounting number of tanks around the site.”