Behind the scenes, system sniffs for biological attacks –

Today, eight years after the anthrax attacks, the system Slezak’s research team started, known as BioWatch, is quietly operating in more than 30 cities.

A federally funded, locally run program with an $80 million annual budget, it depends on a network of vacuum pumps that draw surrounding air through filters, sniffing for signs of biological agents.

The pumps’ precise locations are secret, but they are in high-traffic destinations such as subway stations and where prevailing winds might carry a toxic plume. Each day, technicians retrieve their filters and carry them to public health laboratories, where scientists test for the genetic fingerprints of a top-secret list of biological threats.

The program has made the USA dramatically better prepared for a biological attack — but it also has vulnerabilities, acknowledges Robert Hooks, a deputy assistant secretary at the Department of Homeland Security Office of Health Affairs who now oversees the program for DHS.