Human error part of the cause behind Denel explosion, finds report
The findings of the probe into the accident on September 3 last year at the Rheinmetall Denel Munition (RDM) factory were released yesterday. They were also shared with families of the deceased and staff members at the factory.
The investigation was conducted by an experienced multidisciplinary internal team with external assistance, and guided by the company's statutory obligations under the Occupational Health and Safety Act.
The N16 building, where the incident occurred, was used for blending large volumes of propellant from smaller sub-lots. At the time of the incident, sub-lots of single base propellant were being blended into one homogenous final lot. Propellant had been safely blended at the N16 facility since it commenced operations in the 1980s without any incident.
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.
Investigation leader Rod Keyser said: “The investigation team therefore 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, or expected 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, as far as the investigation team has been able to determine, a previously unidentified and unforeseen hazard across the industry internationally,” Keyser said.
Bradley Tandy, 19, who was an operator at the factory, was among the eight killed in the explosion. His family dismissed the report, accusing RDM of not taking accountability.
“They are not taking the fault for it. I told them that this is rubbish. It is if I commit a murder and I investigate myself and I find myself not guilty for a crime I committed. They feel nothing for us and all we want is answers,” said Brenden Manual, Bradley’s brother.
Most of the families the Cape Argus spoke too refrained from commenting but indicated that they are unhappy with the findings.
Stevon Isaacs, 51, team leader was also among the eight his wife was too distraught to speak to the media, “I am not feeling well after hearing the findings. I will speak at a later stage but I am not ready,” said Maureen Isaccs.@MarvinCharles17