December 21, 2001 Saving the Written Word: Library of Congress Awards Mass Deacidification Contract

Press Contact: Helen Dalrymple (202) 707-1940

The Library has awarded a contract to Pittsburgh-based Preservation Technologies L.P. (PTLP) that will save 1 million books and at least 5 million manuscript sheets from further acid deterioration.

This contract, the third awarded to PTLP since 1995, will permit the Library to increase preservation productivity and save increasing quantities of endangered materials over time. The contract calls for ramping up treatment during the remaining four years of the contract, FY 2002- FY 2005, increasing annual book deacidification from 100,000 to more than 250,000 books per year by the fifth and final year.

Congress has demonstrated continued support for the Library's plans to save millions of books and manuscripts by approving funding for this important endeavor.

As the national library and the official library for the U.S. Congress, the Library of Congress has focused its early mass deacidification efforts primarily on collections of Americana. The deterioration of acid-containing paper presents a formidable challenge, because this degradation undermines the use and long-term preservation of library collections and archival materials worldwide. The Library of Congress has provided leadership over several decades in the development and evaluation of mass deacidification processes and their application to valuable, at-risk book collections and other paper-based items to achieve economies of scale.

With strong support from Congress, the Library has worked with Preservation Technologies under two previous contracts to deacidify more than 400,000 books, using the Bookkeeper deacidification technology that was pioneered by PTLP. The Bookkeeper process exposes paper to acid-neutralizing chemicals. Using a suspension of magnesium oxide particles to neutralize the acid and leave a protective alkaline reserve, Bookkeeper halts deterioration and adds hundreds of years to the useful life of paper.

Under the new contract, the Library will continue to provide training and oversight to PTLP staff who select books for treatment; charge out, pack, and ship volumes to the deacidification plant in Cranberry Township, Pennsylvania; and then reshelve books following treatment. Library staff provide contract administration and quality control over the selection and refiling of books as well as laboratory testing to monitor the effectiveness of treatment. Library staff have also developed procedures to ensure that information about each deacidified book is captured in the holdings record in the Library's bibliographic database.

Preservation Technologies has engineered new horizontal treatment cylinders that it uses to offer deacidification services to libraries and archives for the treatment of loose manuscripts and other items in unbound formats. The Library's new contract authorizes PTLP to build and install a horizontal manuscript treater and a Bookkeeper spray booth in a Library building on Capitol Hill. This will enable the Library to treat large quantities of paper-based materials in nonbook formats, such as newspapers, manuscripts, maps, music scores, pamphlets, and posters. Additional information about the Library's mass deacidification program is available on the Library's Web site at or by contacting the Library's preservation projects director, Kenneth Harris, at (202) 707-1054 or by e-mail at


PR 01-155
ISSN 0731-3527