Is it possible for a cyber-terrorist to hack into a city's water distribution system and poison thousands? Or disrupt air traffic communications to cause two airplanes to collide? Or create a surge in the power grid that would leave millions of people in the dark?

These are the types of questions pondered by the so-called Red Teams, based at Sandia National Laboratories here.

On the fifth anniversary of the Sept. 11 terrorist attacks on New York and Washington, these scenarios are front and center for Sandia, the Department of Homeland Security and law enforcement agencies across the United States.

The Red Teams' job is to anticipate cyber-terrorism, create contingency plans that assume the worst and ultimately thwart a pending attack by plugging existing holes.

Michael Skroch, leader of the Red Teams, said utilities and government agencies are increasingly at risk as they replace custom IT systems created in the 1950s and 1960s with less expensive, off-the-shelf Windows and Unix systems that incidentally are easier marks for hackers. The older systems were secure because they weren't well-known and had limited contact with other systems.

Thus, "It's clear that the threat and risk level has never been higher for cyber-security," Skroch said.

In layman's terms, Sandia's Red Teams are hired by countries and companies to anticipate and stop cyber-terrorism and other security breaches before they happen.