Deficiencies by both Shell and Gas Network Ireland have been identified by the Commission for Regulation of Utilities (CRU) following an investigation into an incident last year where odourless gas was pumped into a gas network in Co Mayo.
A computer system upgrade at the Bellanaboy Gas terminal site in north Mayo was the cause of the incident , that required 10,000 homes and business in Mayo and Galway to switch off their gas for three days last September.
The finding was made in a report published today by the CRU.
The report says the problem arose following a computer system upgrade at the Bellanaboy site and procedures have been put in place to ensure it will not happen again.
The system was shut down to facilitate the upgrade, and caused a different computer system to go into default mode.
However, the procedures for the start-up process after the system upgrade on 21st September 2017 did not include a step requiring the operator to reset the odourant injection system to inject odourant.
Shell EP Ireland identified that odourless gas had been injected in the gas network system at 2am, and by 7am the natural gas emergency plan was activated.
All affected gas was directed back to the terminal and flared off to remove the non-odourised gas from the system.
Mayo-based Minister Michael Ring called on the CRU to investigate the incident.
The investigation also found some deficiencies on the part of Gas Networks Ireland.
Enforcement actions were taken against both parties and the report concludes that deficiencies in operating procedures that led to the incident have been rectified.