blue ice

Noun

blue ice (uncountable)

1. Ice that is blue in colour, formed by compressed snow on a glacier having its air bubbles squeezed out.
   • Antarctica is the best place in the world to find meteorites, and the search for Antarctic meteorites begins with the search for blue ice.1997, Pat Dasch, Allan Treiman, Blue Ice in Antarctica, Lunar and Planetary Institute
   • Tourists on a boat trip in Mount Cook National Park were subject to a rare treat yesterday, when a section of densely compressed blue ice at the base of an iceberg was briefly visible.2011 January 14, Eveline Harvey, “New Zealand blue ice sighting an unexpected treat for tourists”, in New Zealand Herald
2. Human waste that has leaked from an aircraft, frozen at high altitude, and fallen to earth.
   • Cadamore believes the mess came from an airplane. In the airline industry, it's euphemistically known as blue ice. Most people have far less judicious names for it. Such waste apparently is caused by leaks in airplane lavatories.2002 November 21, Mark Belko, The sky is falling? Uh, not exactly, post-gazette.com
   • A chunk of blue ice, apparently from the holding tank of an aircraft toilet, ripped a hole in an elderly couple's roof and destroyed a bed.2006 October 20, “Toilet Ice Rips Hole in Couple's Roof”, in Fox News