U.S. helicopters over Bay Area scanning for radiation - San Jose Mercury News

Helicopters will be flying low over San Francisco, Oakland, Berkeley and Pacifica through Saturday to record natural radiation levels, federal authorities said Monday.

The flyovers are part of research by two federal security agencies to set baselines for radioactivity in the event of a nuclear accident or terrorism.

The helicopters will fly a grid pattern about 300 feet above the ground, covering about 70 square miles for the Department of Homeland Security and the National Nuclear Security Administration.

The Bay Area scans will include the areas near the Oakland-Berkeley border, along the coast in Pacifica and several areas in San Francisco.