Since the nationwide network of air samplers that make up BioWatch were first deployed in 2003, officials at the Lawrence Livermore National Laboratory have filed a number of patent applications aimed at improving the system's reliability, saying its detection capabilities were "inadequate," the Los Angeles Times reported Thursday.
A patent application filed on behalf of Livermore scientists in December 2006 cited a "higher than acceptable rate of false positive ... results."
"False positive results lead to confusion regarding whether [a pathogen] is actually present and whether protective measures should immediately be implemented," the application noted.
The documents contradict assertions by the Department of Homeland Security, which oversees BioWatch, have defended the system, asserting it has performed flawlessly.
"There has never been a false positive result," Alexander Garza, the department's chief medical officer, said last month.
The $1 billion system consists of detection equipment installed in more than 30 U.S. cities and at major spectator events including Super Bowls and national political conventions.
Homeland Security officials in Washington, asked if any of the patented changes have been incorporated in Bio Watch, declined comment, citing "security concerns," the Times said.