The Control of Major Accident Hazards Regulations 1999 (COMAH) Regulation 19(4) places duties on the Competent Authority in the event of a report of a major accident to:
The Competent Authority led by SEPA carried out an investigation into the environmental impact of the three incidents and the effectiveness and suitability of the emergency response plans and contingency arrangements that were in place to deal with the incidents from an environmental perspective. At the time of the incidents there was some public concern about the smoky flaring which occurred during the power distribution failure and MP steam main rupture incidents.
None of the three incidents resulted in a major accident to the environment (MATTE) as defined in the COMAH Regulations. The Competent Authority investigations revealed the following.
For the power distribution failure a combination of quick and effective actions by individuals minimised the environmental consequences.
For the MP steam main rupture incident although only steam/condensate was lost directly to the environment as a result of the pipework failure the loss of steam to the South Side of the Complex resulted in significant disruption to operations at the Complex and some smoky flaring.
For the FCCU fire contaminated firewater containing hydrocarbons from the plant was generated in excess of the capacity of the stormwater retention facilities on-site and this resulted in the release of untreated firewater direct to the River Forth. Smoke and combustion products were also generated as a result of the fire. However, subsequent analysis of the surrounding environment both on and off-site showed no sign of significant levels of contamination as a result of the incident.
The FCCU has several very small radioactive sources which are used for non-intrusive level measurement in the catalyst section. These were not involved in or affected by the fire.
Overall the investigation concluded that the emergency response met its COMAH objectives in preventing, or limiting the environmental consequences of the three incidents and no significant environmental consequences were identified. Several key areas worthy of follow-up were identified by both BP and the Competent Authority during the investigations and are detailed below.
The power station back-up and stand-by effluent pumping provision was less than adequate. As a consequence of the power failure the pumps for the culverts beneath Bo’ness Road failed and this allowed the culverts to flood;
Telephone computer communications and effluent system instrumentation suffered problems with their uninterruptible power supply (UPS) facilities;
The pre-fire emergency plan for the FCCU (and other installations) did not include reference to the presence of radioactive substances on the plant;
The storm tank capacity was insufficient for the combination of the preceding period of heavy rainfall and the volume of fire fighting water used. The original design for storm water retention capacity specified three tanks but only two had been installed. The assumed available total tank capacity was also reduced by the necessity to keep a minimum working level in the tanks at all times;
The effluent treatment plant contingency plan did not consider the range of substances, including asbestos, which might be released during a fire or major incident. As such no special precautions had been considered for sludge disposal in the event that these substances were released;
Environmental lessons learned from previous incidents were not adequately communicated across the Complex.
BP has implemented a range of measures to address these issues. Emergency response plans have now been updated to an agreed format and include reference where required to radioactive sources. Storm water tank capacity is being reviewed as part of the Complex sustaining capital programme. Procedures have been established to address the possible release of a range of substances into the effluent treatment plant during a fire or major incident.