INCIDENT
Prior to the 2008 incident, the methomyl unit at the Institute facility had been shut down for two major equipment upgrades: the DCS had been replaced and the old carbon steel residue treater vessel had been replaced with a new stainless steel pressure vessel.
In this particular case, a new DCS from a new vendor was installed to replace an aging system that was beginning to cause operational problems. On an earlier project in 2007, the DCS vendor and system integrator that installed the system had worked with Bayer to train the Larvin operators, and by early 2008, they were operating comfortably with the new system. When it was time to upgrade the methomyl unit DCS, management decided such formal training was too costly and unnecessary, in the belief that operators had seen enough of how the new system worked from the Larvin upgrade.