On Oct. 9, 2013, an explosion and fire at a Dow Chemical electronic materials facility in North Andover, Mass., led to the death of production operator Carlos A. Amaral, 51. According to a statement released by Dow and dated the end of January, the company’s investigation into the incident concluded that:
• An employee sustained injuries as a result of the overpressure of a small stainless steel manufacturing vessel during an operation associated with a Trimethylindium (TMI) manufacturing batch.
• An undesired and unexpected reactive chemical event occurred within the vessel as the employee was transporting the vessel from the glove box to the next manufacturing unit for further processing.
• The overpressure resulted in a release of reacted and unreacted materials and a fire.
The most highly probable cause of the unplanned event was the ingress of cleaning liquid from the cavity space of the ball valve into the crude TMI. Due to the nature of the event, it is impossible to completely validate this conclusion.
I asked Jeremy Cole, business communications manager at Dow Electronic Materials, whether Dow is changing anything regarding cleaning or other handling of the reaction vessel. He said yes, but so far he has declined to provide additional details.
The federal Occupational Safety & Health Administration is investigating the incident, because Massachusetts does not have its own occupational safety and health program. OSHA currently lists the case as open.
Feb. 26 update–Some more information from Dow’s Cole:
the following is the facility’s action plan:
• Prior to TMI production restart, the facility will consider alternate cleaning processes that use cleaning materials that do not react with TMI. If an alternate cleaning process is not feasible, the facility will define a means to confirm the absence of cleaning materials in void spaces and the vessel prior to addition of raw materials.
• The facility will consider modifications to the manufacturing process to increase the tolerance of intrusion of small amounts of cleaning materials as well as variability of raw materials.
• The facility will conduct a review of its Process Hazard Analyses and determine whether any improvements are recommended. Improvements will be captured in appropriate process documentation.