In early 1970, the main U. S. Post Office facility in Baltimore, Maryland, was eager to showcase its modern electro-mechanical sorting machines.
Designed to process tens of thousands of letters per hour, the automated system was hailed as the future of mail delivery. However, a catastrophic alignment failure on a humid April morning turned the technological marvel into a mechanical paper shredder. A combination of damp air, slightly oversized envelopes, and a jammed optical sensor caused a primary sorter to continuously route mail into an unmonitored internal maintenance chute behind the main conveyor belt.
Over the course of 48 hours, the machine quietly devoured roughly 15,000 pieces of mail without dropping a single error code. The disaster came to light when thousands of local retirees noticed that their monthly pension and Social Security checks were missing. As panic spread and phone lines at local banks jammed with inquiries, postal inspectors launched an immediate investigation.
Expecting a highway mail truck robbery, investigators instead traced a faint burning paper odor to the heart of the automated sorting room. Technicians removed the outer casing of the machine to reveal a compressed, three-foot-wide wall of paper dubbed the paper glacier. Dozens of off-duty postal employees volunteered to work overnight shifts using flashlights, tweezers, and rolls of scotch tape to carefully extract, iron out, and reassemble thousands of torn documents.
Thanks to their tireless efforts, over 90 percent of the lost pension checks were ultimately salvaged and delivered in plastic sleeves accompanied by a formal apology for unusual mechanical friction.