Pollution
Humain
Environnement
Economique

During the afternoon, emulsion was projected into a cartridge loading workshop for explosives closed for the weekend; no one was hurt.

The day before resuming manufacturing, the installation’s water heater needed to be warmed by the on-call supervisor. The supervisor noticed an anomaly (ambient temperature instead of 40°C) and tried to solve the problem on his own.

This person was not part of the manufacturing staff and was relatively unfamiliar with the installation; he activated the button identified as “pump” on an electrical cabinet placed in the utility room, believing the pump on the heating circuit in this room would turn on. He observed a variation in displayed temperature and was convinced that the problem had been resolved. In reality, the button started up the pump for transferring emulsion to the cartridge loaders, and this pump continued to operate even after the supervisor had left.

This pump transferred product contained in the supply circuit connecting the temperature holding tank to the cartridge hopper. At ambient temperature, the pasty product presented excessive viscosity to be normally pumped (with transfer temperature = 80°C). The pump first emptied the circuit, then a cavity. The rotor was idling and wound up heating at a higher temperature.

The heating generated a thermal reaction of residual product in the pump, thus causing a pneumatic projection inside the workshop (floor, walls and ceiling) of emulsion remaining in the pipeline upstream of the circuit and then on the return end in the supply tank.

The on-call supervisor returned to the premises at 7 pm to verify the circuit and once again observed the temperature anomaly. He did not enter the production workshop, instead leaving a memo for the on-duty electrician, who became aware of the incident around 8 pm and promptly informed plant management.

Upon completing a risk analysis, the unit was cleaned; all spattered substances were recovered and destroyed by incineration. The pump was replaced and the supply circuit refurbished. No impacts were recorded either on other plant units or on the environment.

An internal investigation commission (composed of members of the Workplace Hygiene Committee, manufacturing department and Health & Safety Group) proposed the following corrective measures, which were undertaken and extended to all site facilities (whenever pertinent):

  • a display within the utility room of the procedure for restarting the heater programmer, along with the equipment to activate and protocol to adopt in the case of anomaly;
  • relocation of transfer pump controls from the utility room to the manufacturing workshop and servo-control of the pump operation authorisation at a minimum emulsion temperature;
  • electrical supply cut-off (excluding the heater) outside of manufacturing activities;
  • personnel information dissemination and awareness-building;
  • analysis of the on-call supervisor’s function and of staff’s capability to fulfil their assigned missions.