Company procedures called for a PSSR (pre-startup safety review) to be run for the methomyl unit before it was restarted. This was a complex process that was supposed to prove that all the equipment and safety devices were in order, allowing the unit to run correctly and safely.
This was no simple restart. Bayer had replaced the DCS during the outage, installing a completely new system to replace a platform that had been running for more than 20 years.
The plant was under pressure to get the unit running again because the demand for Larvin (the specific pesticide product) was seasonal and orders had to be filled within a critical time frame. Methomyl, a key ingredient of Larvin, was being pulled from inventory, but there was not enough to fulfill demand so production needed to get started without delay. Consequently, Bayer had operators, engineering staff and contractors working around the clock to finalize all the installations, calibration and checking.