After my last column about the sunken oil tanker SS Montebello, reader Stanley Crawford asked me about the fate of the USS Independence CVL-22, a World War II Navy vessel he'd heard had been sunk with radioactive waste off the Farallones Islands near San Francisco. I'd previously written about nuclear dumping there.
Jim Delgado, director of the Maritime Heritage Program of NOAA's National Marine Sanctuary system, is an archaeologist who spent four years diving and assessing radiated ships sunk off the Pacific's Bikini Atoll in the 1980s and 1990s. "Our team always thought that the ships sunk elsewhere would add invaluable information on questions of blast damage, radiation and ongoing questions about corrosion and any potential impacts to the environment," he told me.
Delgado said the Independence was the lead ship for a series of fast carriers built atop cruiser hulls in the South Pacific, then off the Philippines, Okinawa and Japan. After World War II, it was assigned to "Operation Crossroads," the atomic tests at Bikini. It was moored 560 yards from ground zero for the first test on July 1, 1946. The superstructure was blown off, and the flight deck was buckled by peak overpressures and heat damage, including several fires caused by the blast.
Moored 1,390 yards from the second test on July 25, Independence wasn't further damaged but was irradiated. When boarded Aug. 18, it's radioactivity limited personnel's time on board. It was towed to Hunter's Point Naval Shipyard in San Francisco in June 1947 to be the platform for the Navy's radiological decontamination school, later called the Naval Radiological Defense Laboratory, until December 1950.
The Navy sunk the Independence off the Farallones in 1951 in an area used as a waste dump from 1946 to 1970. A 1,000 foot long sonar "image" located during a U.S. Geological Survey assessment in 1990 was tentatively identified as USS Independence in 500 fathoms in the middle of an estimated 47,500 drums of radioactive waste. The wreck, which has also been charted by the NOAA ship Okeanos Explorer, reportedly includes discarded hazmat gear sealed in barrels aboard such as boots, suits, and respirators used in the laboratory, as well as sand used to blast clean the irradiated metal surfaces.
While the oil tanker Montebello has been surveyed extensively, no dives, or imagery or assessment of the Independence have been conducted. Other Crossroads atomic target vessels have been assessed, including those sunk at Bikini and Kwajalein atolls, by the U.S. National Park Service.
Delgado said he believes the Independence can yield valuable archaeological data and a useful environmental assessment. "The other Crossroads vessels, with low levels of radiation, exhibit corrosion characteristics and variable levels of marine growth that may be indicative of either their shallow depth in an exposed lagoon, or from radioactive trace levels in their steel," he told me. At an estimated 1,000 meter depth, the Independence provides an opportunity for a comparative assessment. There are currently no plans or funding for such a study.
Dan Haifley is executive director of O'Neill Sea Odyssey. He can be reached at email@example.com.