Process Safety Beacon: One incident with two lessons
On February 1, 2022, a chlorine gas mixture was released at a facility in Memphis, Tennessee. Three workers required treatment for exposure to the toxic vapor. On the day of the incident, an operator was assigned to refill a . tank containing a mixture of sodium hypochlorite, sodium hydroxide, and sodium chloride (“bleach solution”). A mixture of nitric acid and phosphoric acid (“acid solution”) and the bleach solution were stored in separate 330gallon (1249 L) Intermediate Bulk Containers (IBC or totes) (Figures 2 & 3) in the same area. The trade names of the materials on the totes differed only by one letter (‘Dibac’ versus ‘Dilac’). The operator inadvertently transferred acid instead of bleach solution into the bleach solution tank, (blue circle, Figure 1) causing a chemical reaction that released the vapor cloud containing chlorine gas. Emergency responders transported 10 employees to the hospital. This incident was discussed in the June 2026 Beacon focused on training.
Did you know?
- Many containers look the same. That makes proper labeling critical.
- Vendor brand names may be very similar. Carefully verify the identity of materials.
- Employees handling hazardous chemicals must be trained on the hazards of those chemicals and how to identify the materials they are handling.
- Chemical receiving systems, whether in containers or bulk, heavily rely on administrative controls. It is important to follow their procedures and be attentive to details all the time. A brief lapse in attention can result in a serious event.
What can you do?
- Always follow procedures for handling materials in bulk or in containers, whether as a customer or filling them as a supplier. If there are errors in the procedure, mark-up the errors and give them to your supervisor for editing.
- When handling material containers, check the labeling against the procedure to ensure the material is the correct one.
- Pay extra attention to the labels that are on the container from the vendor. Even very small containers need to be properly labelled.
- Bulk shipments have different types of labeling. When receiving these, verify the contents before off-loading. Some companies sample the shipment for lab analysis to verify the contents versus accepting shipping paperwork.
- When shipping bulk containers, verify all the documentation is complete and correct.
Proper identification of materials is key to safe operation !
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Source: ©AIChE 2026. All rights reserved.