In New York, the prototypes repeatedly generated false readings, prompting officials there to demand their removal.

The tests in Utah and Washington found that the automated units could detect a pathogen only if exposed to concentrations far exceeding the levels that can sicken or kill.

Before President Obama nominated her in 2009 to be a Homeland Security Department undersecretary, O'Toole studied BioWatch as the founder and chief executive of the University of Pittsburgh's Center for Biosecurity. She told a House Homeland Security subcommittee on March 29, 2007, that "different and more useful" biodefense spending was needed to protect the nation.

Building digital links among hospitals, HMOs and local public health agencies "would be far more cost-effective than funds spent on future generations of BioWatch," she testified.

Though she has not spoken publicly for or against Generation 3 since joining the Obama administration, O'Toole told the same House subcommittee on Feb. 25, 2010, that it was "imperative" that the automated system "be carefully evaluated and ... tested in realistic field conditions before large technology acquisition investments are made."

O'Toole said scientists under her supervision would "continue to work collaboratively to conduct and oversee rigorous developmental and operational tests of the proposed Gen 3."

Her reservations notwithstanding, enthusiasm for Generation 3 has persisted within the Homeland Security Department. On March 29, the department's chief medical officer, Dr. Alexander Garza, told a House subcommittee that deploying Generation 3 would be "imperative to saving lives."

On Sept. 13, Garza told a congressional hearing that the department would not follow the Government Accountability Office's recommendation to halt contracting activities for Generation 3 so the technology and potential alternatives could be reassessed.

Chandler, the Homeland Security spokesman, said a unit headed by Garza would "pursue rigorous operational testing and evaluation of candidate Generation 3 technologies to make an informed decision before deployment."

--

david.willman@latimes.com