Steel doors are kept locked. Concealed heavy-gauge wire reinforces the false ceiling and cinder block walls, and motion detectors inside and out guard against intruders.
A special alarm system can summon security faster than a call to police.
The treasure housed in these vaults, however, is not diamonds, rare art or gold bullion. It's millions of secret company documents gathered for Minnesota's lawsuit accusing tobacco giants of selling a product they knew was dangerous and addictive.
The products at issue _ cigarettes _ are banned from this unique legal library. They're a fire hazard.
Nine other states have similar lawsuits pending to recover money spent treating tobacco-related illnesses, and more are expected. But Minnesota's lawsuit is further along and this collection of documents has come to be considered the national depository.
"What's so historic about this place is the magnitude of this production," said Minneapolis attorney Susan Nelson, representing the state and co-plaintiff Blue Cross Blue Shield. "The vast majority of these documents have never been seen by anyone outside the tobacco industry."
Some of the documents already have surfaced and made news. A once-secret R. J. Reynolds report alleged that Philip Morris and Brown & Williamson boosted sales by deliberately enhancing their cigarettes' nicotine levels.
Many of the records are available for all the lawyers in the case to look at in a pretrial process called discovery. But some are considered competitive trade secrets that only the state's attorneys may look at _ the reason for the strict security.
The defendants initially wanted to hold on to their private documents and have attorneys for the state and Blue Cross visit each company headquarters around the country, but a judge ordered both sides to create one central collection point.
The tobacco companies recently granted permission for tours by reporters but refused to let in photographers, worried that a picture could be enlarged and reveal trade secrets.
The document repository occupies a one-time store in a small strip mall in an industrial area north of downtown Minneapolis.
But past a locked wooden door inside the brick, one-story building are locked steel doors on storerooms for the U.S. defendants: Philip Morris Inc., R. J. Reynolds Tobacco Co., Brown & Williamson Tobacco Corp., Lorillard Tobacco Co., The American Tobacco Co., Liggett Group Inc., The Council for Tobacco Research U.S.A. Inc. and The Tobacco Institute Inc.
Some have one-room storerooms to themselves. Others share.
The warehouse holds about 5-million pages, with an additional 5-million or so expected by the time the case goes to trial, probably in 1998.
Shelves are piled high with carefully numbered boxes of documents. Not even the lawyers can enter these rooms; they must request specific files to be fetched by security employees.
"The tobacco companies are obviously competitive with one another and don't want each other seeing their documents," said Peter Sipkins, a Minneapolis attorney representing the companies.
In contrast, the storage room for documents from the state and Blue Cross Blue Shield has no door.
"We don't have anything to hide," said Joe Loveland, spokesman for state Attorney General Hubert Humphrey III.