WASHINGTON-While last week's discovery of a foiled terrorist plot sent shock waves through the international travel arena, U.S. businesses largely acknowledged the heightened threat levels from the Department of Homeland Security with measures such as travel advisories and notifications of the elevated threat levels to employees.

About 71 percent of respondents to a Security Director NewsPoll said they did not officially raise the threat level within their own facilities, despite DHS officials temporarily raising to red, or severe, the threat level for flights originating from the United Kingdom to the United States. However, nearly 70 percent reported that they do follow DHS' threat advisory levels, as it pertains to their vertical industry, as part of their security programs.

"It's a good broad-based gauge from which to evaluate your standing at any particular time," said Chris Grniet, vice president of Kroll's security consulting group, but "each security group has to make their own assessment" of what it means to them.

"In the example of today's raise in threat level, it is pertinent to our local airport," said Shanna Kittell, security administrator for the City of Boise. "Other than making our employees aware of the raise and having information available for travelers, this particular threat increase does not automatically cause an increase at all of our facilities or mandate considerable action. An event would be another matter."

For some, this means communicating to employees such precautions as posting an extra security officer to check bags and briefcases in the lobby or an additional guard in the parking lot, said Dan Kropp, president of security consultancy D.H. Kropp & Associates. Security may also tell their forces to be on the lookout for liquid containers, Grniet said.

"Your average company might not have done a whole lot at their buildings (last week)," Kropp said, "but I think we'll realize the potential seriousness of this over the next couple of weeks."

And while only 28 percent of NewsPoll respondents said they did increase security measures at their facilities, about 65 percent reported notifying employees about the incident.

Most of the concerns surrounding the latest developments, in which British authorities arrested more than 20 individuals who allegedly planned to target 10 airliners bound for U.S. cities with fluid explosives, revolve around travel security. About 44 percent of readers who responded to the survey said they issued travel advisories to employees.