SIMI VALLEY, Calif. (AP) — Lingering radioactive contamination exists at a former rocket test lab outside of Los Angeles that was the site of a partial nuclear meltdown, federal environmental regulators said Wednesday. The Environmental Protection Agency launched a $42 million study to investigate radioactive pollution at the Santa Susana Field Laboratory, 25 miles northwest of downtown Los Angeles. Technicians collected 3,735 soil samples from a corner of the 2,850-acre hilltop lab where most of the testing was done. Of those, they found about 10 percent contained radioactive concentrations exceeding background levels. Most of the contaminated soil was found in places like the materials handling facility that were previously cleaned, but it looked like "isolated spots were missed," said Mary Aycock, an EPA Superfund remedial project manager.

Radioactive contamination at the Treasure Island Naval Station, where San Francisco plans to build a high-rise community for 20,000 residents, is more widespread than previously disclosed, according to a new U.S. Navy report and other documents obtained by The Bay Citizen.

The draft report, dated Aug. 6, marks the first time the Navy has fully acknowledged that the island, created from landfill in 1937, was used as a repair and salvage operation for a Pacific fleet exposed to atomic blasts during the Cold War. The report came in response to state regulators, who pressed for details after cleanup workers found radioactive waste in unexpected locations.

Known potential sources of radiation on the island included a nuclear training ship intentionally doused in radiation and even glow-in-the-dark buttons handed out at the 1939-1940 Golden Gate International Exposition held on the island.