By Erin Sherbert
By Erin Sherbert
By Leif Haven
By Erin Sherbert
By Chris Roberts
By Kate Conger
By Brian Rinker
By Rachel Swan
A small taste of the toxics at the shipyard: At a place called Parcel C, a 77-acre area forming the eastern prong of the base, Navy workers discovered ground water deposits, or plumes, of vinyl chloride, one of seven known cancer-causing agents found at the shipyard, and trichloroethylene (TCE), a chemical precursor of vinyl chloride believed to be carcinogenic on its own. In some tests for vinyl chloride, the Navy's environmental consultant found the chemical at 36,000 times EPA warning levels.
Tests measured TCE at more than 55,000 times the regulatory threshold. One vinyl chloride plume is 2.8 acres in size. Both of these chemicals are capable of turning into gas and entering buildings where people could breathe them unknowingly. Both TCE and vinyl chloride deposits are within the area where the bay interacts with the ground water, endangering wildlife.
To the west of that site, on what the Navy calls Parcel B, nickel has been found in the ground water at more than 850 times the federal regulatory threshold for aquatic wildlife safety and more than 1,000 times the same standard set by California water quality officials. Again, the plume is within the area where the bay water interacts with the ground water. TCE in the soil nearby measured 306 times the EPA standard for residential use.
And that type of pollution is just what the Navy knows about and has revealed. At the Hunters Point shipyard, when it comes to toxics, the unknowns outnumber the knowns. Perhaps the biggest unknown at the base is what lurks offshore in the bay mud that serves as the crucible of life for the local ecosystem.
It's called Parcel F, and it measures 443 acres. Tests have just begun on the sediment in the underwater area, which is probably the most serious threat to the aquatic habitat. Already, the EPA says, the results are showing that metals and other compounds in the muddy bottom seem to pose an ecological risk.
Numerous federally protected or endangered species call the shipyard area home, including the California sea lion and harbor seal, both protected under the Marine Mammal Protection Act. Fishing activity in the area is common, including the harvesting of herring, halibut, and anchovy.
On the shipyard land itself there's a veritable field guide of varmints and critters, and the birds that eat them. Plant- and seed-eaters include Botta's pocket gophers, California meadow voles, deer mice, black tailed hares, mourning doves, house finches, and sparrows. Insect fanciers include the mockingbird and meadowlark. Loggerhead shrikes and American kestrels prefer the mice and the lizards. Top predators include the majestic and hardy peregrine falcon, the red-shouldered hawk, and the red fox.
Wetlands dot the base and provide a home for numerous resident and migratory shorebirds. At high tide osprey, great blue heron, great egret, and belted kingfisher forage for food in the wetlands.
This ecosystem could be seriously disrupted by toxics in the sediment. The sediment supports crustaceans, bivalves, and other low-level bay life. Exposed at low tide, they are dinner for shorebirds. At high tide, they're dinner for fish.
If the mud flat and sediment dwellers are contaminated it's no minor matter. Toxics can bioaccumulate in the birds and fish that feed on them, and the mammals that feed on the birds and fish, decimating entire populations of wildlife.
But shipyard pollution also poses a direct threat to human life. Following EPA guidelines, the Navy has calculated that future workers at the base won't face much of a risk. But residents of new housing built on the former base will be endangered without a proper cleanup, according to Navy tests.
The base contains 224,000 square feet of land that poses a significant cancer risk; in 10 different areas, the inhalation of ground water fumes of vinyl chloride and other volatile compounds has been deemed an unacceptable hazard by the Navy and the EPA. And some 1 million square feet are considered a human health risk due to non-carcinogenic chemicals.
Where toxics pose an unacceptable level of health or ecological risk at the base, the Navy has proposed removing the toxics, or isolating them from people or other animals. Any private developer would be expected to meet the same level of cleanup, according to the EPA. Current cost estimates put the job at $300 million. But this cost estimate is based on a study of less than half the shipyard. The total cost will likely be more.
The vinyl chloride and TCE plumes under large portions of the base are the biggest concern for the EPA and the Navy. They are huge and dangerous to both humans and wildlife. To contain the risk they pose will require a high-tech effort. The Navy and federal regulators have yet to settle on a solution. But what the Navy has proposed illustrates the level of responsibility the city is considering turning over to a private company.
To stop the vinyl chloride and TCE from breaking down into gas and entering buildings or from leaking into the bay, the Navy is proposing to do one or more things, all of them expensive. The proposals include:
* Hauling toxic soil to landfills.
* Monitoring ground water movement and toxicity.
* Building underground walls to block the path of polluted ground water.