A SELF ACCELERATING DECOMPOSITION REACTION KILLS AN OPERATOR

On May 4, 2023, at about 12:40 a.m., a pressure Nutsche filter vessel (“vessel”) exploded at a facility in  Massachusetts. The explosion and fire fatally injured one operator and caused approximately $48 million in loss from property damage, which led to the permanent closure of the facility.

At the time of the incident, the plant was producing a substance called Dekon 139 (“Dekon”). The Dekon had already been synthesized, and excess liquid from the production process had been removed from the solid product (“cake”) within the nitrogen-inerted vessel. The plant used an agitator to smooth the cake and remove lumps that formed during drying to remove the liquid from the cake.                                                                                                                                                                            In post-incident testing, the plant determined that Dekon could undergo exothermic, self-accelerating decomposition when heated to 280 degrees Fahrenheit. The plant learned that Dekon decomposition releases flammable gases, including hydrogen, methane, and carbon monoxide.
In its incident investigation, the plant determined that leading up to the incident, the agitator had loosened and was rubbing a plate at the bottom of the filter dryer vessel, generating heat from friction. The friction likely caused an area of high temperature (“hot spot”) in the Dekon, which likely reached the temperature
necessary for the Dekon to begin decomposition. The decomposition reaction released energy, which increased the temperature of the material in the vessel and caused more Dekon to decompose.                                                                                                                                
The gases produced by the reaction rapidly increased the pressure within the vessel, causing the vessel’s discharge door to open. The released flammable materials (gas and Dekon dust) mixed with atmospheric oxygen and ignited, causing an initial weak explosion. Shortly after that, the vessel’s rupture disc opened, and a second larger explosion occurred when the vessel failed.
One operator was unable to escape the area and was fatally injured.
The CSB estimated that approximately 600 pounds of Dekon decomposed into flammable gases that were consumed during the incident.
Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the explosion and fire was a self-accelerating decomposition reaction of Dekon, which produced flammable gases and released combustible Dekon dust that ignited upon release. Contributing to the incident was the company's incomplete knowledge of the hazards associated with Dekon, including its ability to undergo a self-accelerating decomposition reaction capable of rupturing the reaction vessel.

Source:CSB.gov

Watch "Process Alarm Systems Updates to EEMUA 191 by Andy Brazier" on YouTube

 Watch "Process Alarm Systems Updates to EEMUA 191 by Andy Brazier" on YouTube

 https://youtu.be/xh62GMQ53u0?feature=shared

INCOMPATIBLE CHEMICALS CAUSE H2S RELEASE

 On March 29, 2023, at approximately 5:05 p.m., toxic hydrogen sulfide gas was accidentally released at a paper mill in Kentucky. Exposure to the hydrogen sulfide gas seriously injured one operator and injured two other operators.
At the time of the incident, three operators were tasked with circulating an acid-cleaning solution through process equipment to remove the buildup of solids impairing its performance. This task required an operator to stand directly over a tank and pour solid sulfamic acid powder into its opening.
When these operators added the sulfamic acid powder, the tank should have contained water, but a valve had been left open. This allowed a “weak wash” process stream to enter the tank before the operators added the solid sulfamic acid. The weak wash contained sodium sulfide, which reacted with the sulfamic acid, generating the toxic hydrogen sulfide gas.
Operator 1, who was standing directly over the tank opening (Figure 1), lost consciousness from exposure to the hydrogen sulfide gas that evolved from the tank. Operator 3 was able to call for help over the plant radio system but lost consciousness soon after. Operator 2 was seriously injured after losing consciousness (while trying to help Operator 1), falling to the floor, rolling through a guardrail system, and falling about 11 feet to a lower area of the structure.
Two other Domtar employees heard the distress call and entered the room to help the operators. All three operators regained consciousness. Operator 1 and Operator 3 were able to walk outside without assistance. Emergency responders transported Operator 2 to a hospital for treatment.
The company reported that about 25 pounds of hydrogen sulfide were released.

Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the hydrogen sulfide release was the reaction between the added sulfamic acid and the sodium sulfide in the tank. The company's procedure procedures did not indicate that the weak wash valve should be closed during normal operation, which contributed to the incident. Had the weak wash valve remained closed (or more robustly isolated), sodium sulfide could have been kept out of the tank, preventing the reaction that generated the toxic hydrogen sulfide.

Source:CSB.gov

"Travel Stops on Spring Supports: What Engineers Need to Know" by Piping Technology and Products

The June 2025 process safety beacon talks about an incident that I had experienced with a locked spring hanger. Read the beacon in this link https://ccps.aiche.org/resources/process-safety-beacon/archives/2025/june/english

Piping Technology and products have published a safety alert explaining  "

"Travel Stops on Spring Supports: What Engineers Need to Know"

Read it in this link

https://pipingtech.com/resources/technical-bulletins/safety-alert-installation-spring-supports/

 

 

A FIRE WATER HOSE CAUSES A PUMP TO CRACK AND INJURE A EMPLOYEE

On February 24, 2023, at 9:20 a.m., an accidental release of approximately two gallons of a sodium hydroxide and water solution (“caustic solution”) seriously injured an employee at a facility in South Carolina.
A new pump for unloading caustic solutions from tank trucks was installed at the facility the day before the incident. On the day of the incident, the company used the new pump for the first time. Employees turned on the pump to begin transferring the caustic solution from a tank truck, but the pump failed to move fluid and leaked. The employees planned to disassemble the pump to identify the operational problem.
Before disassembling the pump, it was decided to flush it out with water from a fire hose. This action was taken to prevent employees from getting the caustic solution on their hands when the pump was disassembled. An employee connected a fire hose to the pump and partially opened the valve. The pump could not handle the pressure supplied by the firewater, and the plastic pump casing cracked. Caustic solution and water sprayed out of the pump, seriously injuring one employee.

After the incident, the company modified its caustic unloading system, eliminating the need for an unloading pump.
Probable Cause
Based on the company's investigation, the CSB determined that the probable cause of the incident was the overpressure of a pump casing after pressurized firewater was introduced to the pump.

Source:CSB.gov