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Napolitano urges traveling public to be vigilant

From the London Marathon to the Kentucky Derby, the security plans that had been in place for big, upcoming public gatherings are being reevaluated in the wake of the Boston bombings that killed three people and injured more than 170. NBC's Tom Costello reports

Had the Boston explosions happened a few years ago, the buzz would soon be about the color orange. As in “Code Orange” — the government’s way of indicating a high risk of terrorist attacks under the oft-maligned color-coded Department of Homeland Security terror alert system.

Today, the color chart is history, replaced in 2011 by the National Terrorism Advisory System.

So what should travelers know about the state of airport and mass transit security in the wake of the blasts?

No national alerts have been issued, according to the DHS website. In fact, the agency has never issued an alert under the system, which requires the government to send out “formal, detailed alerts” when it receives information about a specific or credible terrorist threat.

The agency did not respond to an on-the-record request for comment about the process, but in a statement issued Tuesday afternoon, Secretary of Homeland Security Janet Napolitano said there is nothing to suggest at this point that the events in Boston are indicative of a broader plot.

“Out of an abundance of caution, DHS continues to keep in place enhanced security measures at transportation hubs, utilizing measures both seen and unseen,” Napolitano said.

She urged the public to remain vigilant and immediately report any signs of suspicious activity. 

“It is notable that they have not used the (NTAS) system to date,” said Christian Beckner, deputy director of the George Washington University Homeland Security Policy Institute.

“The original color coded Homeland Security Advisory System was so broad that it didn’t lead to effective reactions. This more targeted approach is the right one.”

After the deadly Boston blasts, a number of airports are either beefing up police presence or operating under a “heightened state of alert,” including the three major New York-area airports and Los Angeles International. Airlines are extra vigilant, too, and not taking any chances with suspicious items. On Tuesday, a US Airways flight was remotely parked at Boston Logan International “out of an abundance of caution” so that a bag on board could be examined. The baggage was deemed harmless and the flight taxied to the gate. Airport operations were not impacted.

Related: Reports of suspicious activity spur travel headaches

Regardless of whether or not the government issues a national terror alert, TSA can independently send a security notice to the airlines and recommend additional security measures at airports, Beckner told NBC News.

“That’s more precautionary, not necessarily tied to any specific thing,” he said.

The TSA declined to comment about how the Boston explosions are affecting airport checkpoints, referring all questions to the Department of Homeland Security.

If the government issues an alert under NTAS, it will specify whether there is an “imminent threat” or “elevated threat.” The alert will also explain the potential danger, outline what actions are being taken to keep the public safe, and recommend steps that you can take to protect yourself.

“It’s a vast improvement over the last system,” said Rick Nelson, a senior associate of the Homeland Security and Counterterrorism Program at the Center for Strategic and International Studies.

“I don’t think anybody misses the color coded system except for the late night comedians.”

Each threat alert will have an expiration date so the public doesn’t have to deal with an elevated threat level for an unending period of time, Nelson said. That’s quite a contrast from the previous approach, implemented soon after the 9/11 attacks. Road warriors may remember that the threat level in airports remained at orange for years under the color-coded system.

“It wasn’t really based any credible threat and it really didn’t tell people what to do,” Nelson said. “If I told you the threat level was now red, what did that mean to you as a citizen and what should you do differently? That was always very unclear.”