Inspection Detail

Inspection: 312731425 - Ndk Crystals, Inc.

Inspection Information - Office: Naperville Area Office

Investigation Summary

At approximately 2:36 pm on December 7, 2009, an explosion occurred when producing AT and Optical Crystals in high pressure autoclaves/vessels. The high pressure vessels were manufactured by Engineered Pressure Systems, Inc. Employees were required to load and unload the high pressure vessels with propriety substances. Once the vessels were loaded, the employees monitored the process and performed other duties. During the operation, vessel Number 2 exploded and released high temperature caustic solvent that created a large plume. The pressure blast destroyed the facility and emitted debris onto adjacent properties. A truck driver on an adjacent highway was struck by the flying building material and was killed instantly. The truck driver was not an employee of NDK Crystals. Employees working at the NDK facility received minor injuries such as lacerations and contusions. Employees at the plant were provided some training on the process, but were not provided adequate training on hazard communication and PPE. All employees at the facility spoke English. Employees were provided with some PPE, but only for the loading and unloading process. The preliminary findings were that the explosion was related to stress fractures and corrosion cracking.

Keywords: PRESSURE VESSEL, EXPLOSION, CORROSION, UNTRAINED