In 1959, an unconfined partial meltdown of a sodium reactor at the Santa Susana Field Lab caused such a devastating radiation leak, that many consider it to be the worst nuclear disaster in U.S. history. What intensifies the situation, is that it's located just 30 miles from Downtown Los Angeles. For twenty years, this nuclear meltdown was concealed from the public eye; the resulting contamination never to be fully eradicated. Years ofr subsequent investigations have uncovered a number of catastrophic accidents that occurred on the site as well as decades of improper handling of radioactive materials, including the practice of open air burn pits that spread clouds of radioactive waste across the surrounding valley. SSFL is now believed to be one of the most contaminated sites in the world.