Beginning in 1946, the Navy cleaned dozens of ships pummeled with radioactive debris during offshore atomic weapons tests and housed a nuclear defense laboratory with up to 108 radioactive isotopes at the Hunters Point Shipyard in San Francisco. Navy documents suggest these activities may have contaminated dozens of locations across shipyard, a federal superfund site.
An NBC Bay Area investigation found the Navy identified 91 locations as potentially contaminated in a 2004 report, but never tested hundreds of other buildings and sites within the square-mile plot. The Navy says the "impacted" sites represent a significant portion of the shipyard.
The 2004 report, called a Historical Radiological Assessment, focuses on the radiological history of the site. It is based on documents, maps and firsthand accounts that indicate a building or area could be radiologically contaminated due to past Navy operations.
It is unclear if the Navy has deemed any other sites to be potentially impacted by radioactive contamination since it released its 2004 report. It is also unclear if the cleanup has extended beyond what was initially believed to be contaminated when the assessment was completed.
The Navy recently confirmed it performed additional surface scans for radiation or collected soil samples on a 49-acre area of the shipyard. Some locations within this area were listed as impacted in the original assessment. It soon plans to scan other areas of the shipyard it hasn’t looked at before.
In September, state health inspectors unearthed a radium deck marker in an area that was not identified in the initial Navy report. It was found buried in an embankment within roughly 30 feet of condos currently under construction. The silver dollar-sized objects were commonly used throughout Navy bases to light passageways aboard ships.
The Navy maintains that the portion of the shipyard where the deck marker was found had been used for military housing and administrative buildings. The results from state inspections confirmed radiological activities did not occur there, the Navy said. But the object itself was made to contain radium, and later strontium. Both are radioactive isotopes.
The Navy said there has been no evidence of soil contamination and the area is safe for the public.
Across the street are sites where it appears personnel cleaned ships exposed to nuclear weapons tests in the Pacific during the summer of 1946 — an experiment dubbed "Operation Crossroads."
The ships targeted in these explosions were brought to Hunters Point, where workers sandblasted surfaces to remove radioactive material. They also burned 600,000 gallons of radioactive fuel oil.
The Operation Crossroads buildings and dumping grounds are listed as impacted in the Navy's radiological assessment and are connected to potentially dangerous radionuclides such as cesium, plutonium, radium and strontium.
At least two of those sites appear to have been cleaned by Tetra Tech, the government's lead contractor for the ongoing decontamination project, according to a map provided by the Navy.
The goverment's remediation effort faced questions in 2014 after a former cleanup worker alleged his bosses at Tetra Tech instructed him to replace potentially contaminated soil samples with clean ones and falsify records. Two former supervisors were later sentenced to prison for falsifying documents.
Tetra Tech's work covered large portions of the shipyard, including several of the subdivided parcels. The Navy still owns most of those parcels, which must undergo further testing and possible remediation before being turned over to the city for an ambitious redevelopment plan. In January the Navy announced nearly half of the shipyard’s radiation cleanup is in question after it reviewed Tetra Tech’s work and found inconsistencies in the company’s radiation testing data. The Navy and the Environmental Protection Agency said some of it appears to be fraudulent.
Tetra Tech says it fully stands by its work at the shipyard.
A dozen other contractors have conducted — or will conduct — radiological work. It is unclear exactly where these additional companies have performed work, as the Navy told NBC Bay Area it has not consolidated the locations on a single map.
The Navy has invested nearly $1 billion in the shipyard and awarded Tetra Tech $250 million in cleanup contracts.
When the expansive cleanup process ends, hundreds of new homes and offices will take shape next to others that remain from a bygone era of nuclear experimentation.
The 2004 report includes detailed maps of the entire drainage and sewer systems that snaked through the shipyard
The report logs possible contamination for each line connected to impacted buildings, but there is no comprehensive map of impacted drainage and sewer lines.
The Navy provided NBC Bay Area with a map of trenches that Tetra Tech was tasked with cleaning up, which seemingly trace parts of the drainage and sewer systems. In all, the Navy said 28 miles of storm drains and sewer lines were worked on.
Sites the Navy characterized as radiologically impacted, as well as the work Tetra Tech performed, give a glimpse into which areas of the shipyard the Navy might have targeted for cleanup after the 2004 report was released.
This map includes specifics for sites such as: past uses, contamination ratings, use of radioactive isotopes and recommended future actions. Select a site to read more.
The 2004 assessment includes cleanup work that had been performed up to that point in time on certain sites.
Building 815 sits at the bottom of an embankment in an area bordering Parcel A, which has already been turned over to the city. The hulking seven-story concrete box is listed as the Navy's main radiological defense laboratory from 1955 to 1969.
The building was surveyed five times and cleaned twice before 1980. The report recommends further tests, noting that the building is likely to be found contaminated if it faced tougher modern testing standards. At the time of the report, the building was no longer owned by the Navy.
Several other impacted sites are listed in the Navy’s report as unlikely to be contaminated.
IR 7/18 is the flat dirt and concrete clearing listed as a site for possible Operation Crossroads waste disposal. A 1992 test detected radium, but a survey the following year did not detect radiological anomalies and neither did an EPA test in 1994.
The Navy's 2004 assessment provides a snapshot of any known cleanup efforts and recommendations should a site be contaminated. Given that the report was released more than a decade ago, it is unclear what the current status is for each of the 91 impacted sites.
When developer FivePoint, a spinoff of the Lennar Corp., finishes the ambitious project, the shipyard's skyline will still be defined by the gigantic crane at the southeastern tip of the shipyard.
It towers 500 feet above a paved strip called Gun Mole Pier. This is where a former sailor said he removed deck markers from warships during the height of the Cold War, according to an interview transcript included in the radiological assessment. He recalled wearing special protective clothing and working a special seven-hour shift with no lunch break.