Tempers are flaring over a United States demand to open to scholars and researchers a huge repository of information about the Holocaust contained in the files of the International Tracing Service at Bad Arolsen, Germany.

Based in part on documents gathered by Allied forces as they liberated Nazi concentration camps, the stock of files held by the organization stretches for about 15.5 miles, and holds information on 17.5 million people. It amounts to one of the largest closed archives anywhere.

The collection is unique in its intimate personal detailing of a catastrophe, which is what makes the question of open access so delicate. The papers may reveal who was treated for lice at which camp, what ghoulish medical experiment was conducted on which prisoner and why, who was accused by the Nazis of homosexuality or murder or incest or pedophilia, which Jews collaborated and how they were induced to do so.

Since the end of World War II the Tracing Service, operating as an arm of the International Committee of the Red Cross, has used the files to help people trace the fates of relatives who disappeared into the murderous vortex of Nazi terror. Now, more than 60 years after the end of the war, the United States says that task is largely done and it is time to open up the archive, copy it so that it can also be stored in other countries and make it available to historians.