The library has been ordered by the federal government to destroy documents containing information on public water supplies it received as a member of the Federal Depository Library program.
Government officials have approached about 1,300 libraries across the country that might contain sensitive documents.
In a letter to Ridley Kessler, the federal depository librarian at UNC, the U.S. Government Printing Office called for the destruction of the CD-ROM document "Source-Area Characteristics of Large Public Surface Water Supplies in the Conterminous United States: An Information Resource for Source-Water Assessment."
Kessler received the letter Oct. 12 and said the document is no longer available at Davis Library.
Kessler said he thinks the government fears that terrorists could use information about water supplies in future attacks.
While Kessler said he understands the need for national security today, he said he is disturbed by the demand and that it is an act of censorship. Kessler said the destruction of public documents goes against the mission of both UNC and its libraries.
"This library -- and the University -- has prided itself on free public access of these documents to the people of North Carolina," he said.
Kessler said he fears destroying the document could lead to the destruction of less threatening or more important documents that should not be censored.
"When you have an event like (Sept. 11) it scares everyone to death," he said. "When you have a public that is scared, (censorship) sounds very good."