Following the recent discovery of radioactive material nearby, the Environmental Protection Agency has restricted public access to Ormond Beach wetlands in Oxnard while it oversees the stabilization of massive waste piles generated by a shuttered metal recycling plant.
The radioactive metal thorium, which was found about 100 feet southwest of the slag piles, is considered a health risk after direct or prolonged exposure, officials said. After confirming the contamination last week, EPA contractors fenced off the site Friday and blocked its entrance.
Thorium enters the body through inhaling or swallowing and while most of it is expelled as waste, small amounts can get into the bloodstream or be deposited in bone. The EPA said studies show that inhaling thorium dust causes increased risk of developing bone, lung or pancreatic cancers.
Last month, the EPA began a multimillion-dollar stabilization of the towering piles of recycled waste at the former Halaco Engineering Co. smelting plant.
The EPA's goal is to reshape the slag piles -- higher than 45 feet in some places -- to make them less susceptible to erosion.
Robert Wise, on-scene coordinator with the EPA's emergency response section, said he discovered what appeared to be a strange clay-like substance near the bridge that leads to a walking trail at the end of Perkins Road. Further examination revealed that it was thorium.
"I saw something that looked just like a waste solid," Wise said, "so I sampled it and it came back hot," or radioactive.
Scientists have long known thorium to be present at the beachside site. In 1969, Halaco obtained a radioactive-material license to handle magnesium-thorium alloys found in some scrap metals. But finding the radioactive metal outside the former 43-acre Halaco site was unexpected, Wise said.
For decades, Halaco was considered one of Ventura County's worse polluters; its owners filed for bankruptcy in 2002, and ceased operations two years later. Last September, Chickadee Remediation Co. paid nearly $3 million for the site to restore it for residential development.
Initial sampling suggests there are about 5,000 cubic yards of thorium-laced material, a small amount considering the 28-acre section of the facility containing the slag piles is estimated to hold about 710,000 cubic yards of waste.
Wise said tests at the site indicated the presence of thorium at roughly 10 times the level that EPA standards require for cleanup. But Wise said even such elevated amounts are gauged in picocuries -- an infinitesimally small amount equal to one-trillionth of a curie, the standard measure of radioactivity.
Wise said he hopes to complete the thorium removal by March 15, when the active shorebird nesting season begins. The wetlands are home to numerous species, including the least tern and the snowy plover.