Fatal South African munitions plant explosion caused by faulty product, operator error and electrostatic build-up
05 November 2019
A year after an explosion killed eight employees at a munitions factory near Cape Town, an internal investigation has found that due process was not followed in ensuring the safety of materials.
Representative image: Shutterstock
A report in the Cape Argus described the findings of the probe into the accident on September 3 last year at the Rheinmetall Denel Munition (RDM) factory.
The investigation was conducted by an experienced multidisciplinary internal team with external assistance.
The building where the incident occurred was used for blending large volumes of propellant from smaller sub-lots. It had been carrying out these operations without any incident since the 1980s.
According to the company, all members of the team were fully trained, and the team leader and supervisor both had extensive experience with the material and the operations being executed at the time of the incident.
The investigation established during the mandatory routine testing of sub-lots in the course of the manufacturing process that one sub-lot did not meet the required quality standards.
It was also revealed that due process was not followed and, instead, an attempt to rework the material was made by adding extra graphite to the propellant.
The investigation team concluded that the cause was a combination of human error when excess graphite was added to the material, and a highly complex electrostatic electricity risk which was very unlikely to have been foreseen by the individuals involved.
The investigation established that the most likely cause of the explosion was a build-up of electrostatic electricity in a suspended graphite cloud due to the triboelectric effect (a type of contact electrification in which certain materials become electrically charged) and a subsequent discharge which ignited airborne propellant in the blending drum.
This particular type of electrostatic electricity risk was a previously unidentified and unforeseen hazard across the industry, investigators said.
State prosecutors have yet to decide if the company or its managers should face charges over the deadly explosion.