A final report released on July 31 indicates that the explosion, which occurred as the result of a runaway chemical reaction in a 1,500-gallon process vessel inside the Synthron production building, was a result of a desire by company management to increase sales of the company's paint additives. One worker was fatally burned and 14 others were injured.
The accident occurred when plant managers attempted to fulfill an order for acrylic polymer that exceeded the normal batch size for the product. Instead of making two smaller batches to fill the order, managers decided to make a single, larger batch. Managers decided to add all the extra acrylic monomer during the first stage of the reaction process, which was a critical mistake, as the heat output exceeded the cooling capacity of the condenser, causing a reaction that accelerated out of control.
Operators observed solvent vapor leaking from a hatchway on top of the reactor as the process overheated and pressure built up inside the reactor. Operators fled the production building and gathered just outside a doorway. A flammable vapor cloud formed inside the building, and a short time later it ignited and exploded, destroying the production facility.
Managers Poorly Prepared To Handle Emergency
According to the CSB's investigation, Synthron had gathered only minimal safety information on its polymer-producing processes. Personnel, including the managers, were poorly prepared to recognize the dangers from an uncontrolled chemical reaction, CSB said.
Jim Lay, who lead the Morganton investigation for the CSB, said that most of the management and operations personnel at Synthron had been on the job for less than a year - in some cases for only weeks or months.
“The plant manager, superintendent, vice president, shift operators and chemist all lacked experience in producing polymers,” he said.
In addition, CSB found that Synthron had not performed a systematic safety review - also knows as a process hazard analysis - of the reactor. The facility also failed to install safeguards to automatically detect, prevent or mitigate a runaway reaction.
CSB also concluded that Synthron did not have an evacuation plan in place for an emergency. According to investigators, there was adequate time available to have evacuated all personnel to a safe location after vapor escaped from the reactor hatchway if managers had known what to do in case of such an an emergency.
Parent Company Didn't Provide Oversight
Protex International is Synthron's parent company and although Protex had testing equipment at its European facilities to measure chemical reaction hazards, CSB investigators found that the company did not use it to determine the safety of Synthron's processes or provide adequate technical support to Synthron.
As a result, the CSB recommended that Protex establish a program to follow good industry safety practices for managing reactive hazards at all its remaining U.S. facilities.
“The accident at Synthron emphasizes the need for effective corporate oversight, emergency planning and reactive chemical process training and safeguards,” said CSB Board Member and future CSB Chairman John Bresland. “If these measures had been in place, this accident could have been prevented.”
Calls made to Synthron and Protex International were not returned.