The survey of Border Patrol agents and Customs and Border Protection inspectors was commissioned by the American Federation of Government Employees and carried out by pollster Peter Hart.
Nearly two thirds of those surveyed said they had not been given the "tools, training and support" they need to stop potential terrorists from entering the country, according to a statement issued by the union.
Forty-four percent said the United States is no safer than it had been on Sept. 11, 2001.
The survey also found two-thirds believe the current hiring freeze in the Department of Homeland Security, where both groups of workers are based, is hurting security.
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