Nihon Dempa Kogyo Co., Ltd. or NDK (日本電波工業株式会社,Nihon Dempa Kogyo Kabushiki-gaisha) (TYO: 6779) is one of the world's largest QuartzCrystal Companies, based in Shibuya, Tokyo, Japan .
NDK's Belvidere, IL facility was heavily damaged in 2009 when one of the crystal autoclaves ruptured violently, causing an explosion. A beam from the NDK building killed a man at a nearby gas station, and a shard of the ruptured autoclave's wall injured two others and caused heavy damage in a nearby office building. The rupture was in a crystal-growth autoclave that had undergone stress corrosion cracking and was inadequately inspected; recommendations from a previous incident were ignored. As a result, the autoclave became overstressed and failed completely. [1] Demolition of the facility began in March 2015.[2]