sf naval shipyard 2619Melia Robinson/Business Insider

A sprawling middle-class neighborhood is rising on the site of the retired San Francisco Naval Shipyard in Hunters Point. But before residents arrived at this long-forgotten patch of the city’s waterfront, the area was home to a federally run nuclear test site.

In a secret laboratory used for decades after World War II, the US Navy ran tests on ships exposed to atomic weapons and conducted research about the effects of radiation on living organisms. The shipyard’s closure in 1994 left behind San Francisco’s worst toxic-waste dump.

Developer Five Point, a spinoff of Lennar (the nation’s largest housing builder), has set out to transform the abandoned San Francisco Naval Shipyard into a bustling live-work community with 12,000 new homes and roughly 5 million square feet of office and commercial space.

Business Insider recently explored what is left of the shipyard before the new residential community takes its place. It was not pretty.