CSB finds fatal 2009 NDK explosion resulted from stress corrosion cracking of high-pressure vessel; crystal maker failed to inspect or test vessels and to heed earlier warning about risk to public
Rockford, Illinois, November 14, 2013—An explosion which occurred December 7, 2009, at the NDK Crystal manufacturing company in Belvidere, Illinois, fatally injuring a truck driver at a nearby gas station on the Illinois Tollway, resulted from corrosion in the walls of a pressure vessel, which went uninspected for years. The findings were released in a draft investigation report from the U.S. Chemical Safety Board (CSB).
The CSB also released a safety video on the accident entitled "Falling through the Cracks," which utilizes a computer animation to depict the sequence of events and investigation findings. CSB videos may be viewed at www.CSB.gov or www.youtube.com/uscsb.
The violent rupture occurred in the Number 2 vessel which was growing synthetic quartz crystals at extremely high pressure and temperature. One piece of steel from the building was blown 650 feet, striking the driver who was walking back to his vehicle. Another piece - a vessel fragment weighing over 8,000 pounds - tore through a wall at the facility, skipped across a neighboring parking lot and struck the wall of an automotive supply company where 70 people were working; but only one was injured.
CSB Chairperson Rafael Moure-Eraso said, “Over the years, NDK ignored safety recommendations and warnings that it should regularly inspect the interior walls of the vessels. Because the vessels did not meet requirements of the widely recognized national pressure vessel code, the State of Illinois allowed installation of three of the vessels under a special exemption. In doing so, the vessels were incorrectly put into “non-corrosive” service. The manufacturer of the vessels - including the one that exploded years later - recommended annual inspections, but neither NDK nor the state performed the inspections. This set in motion a near-inevitable catastrophe.”
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