THE ENVIRONMENTAL PROTECTION Agency has found that ESB Networks failed to notify local authorities of 48 cases where “hazardous” oil leaked into the ground from underground heavy-duty electrical cables. 

The EPA report, published today, found there had been 68 historic leaks from the ESB’s fluid-filled underground electricity cables between 1993 and June 2019. It also identified a further seven “current and new” leaks. 

According to the EPA, the locations and scale of each leak has been identified by ESB Networks and “they are now undertaking site specific investigations of each”.

The EPA launched its investigation after RTÉ Investigates and ESB contacted them in relation to records of oil leaks going back over the last two decades in June 2019. 

The RTÉ Investigates programme found that the cables had been leaking thousands of litres of industrial fluid over a sustained period. Other records showed a total of 19,781 litres of oil was leaked from one underground cable over a ten-year period up until 2009.

ESB said the fluid lost from the cable leaks is often a mixture of mineral oil and linear alkylbenzene (LAB) and therefore “must be classified as hazardous”.  

“The fluid used as an insulating liquid in cables was originally mineral oil and more recently linear alkylbenzene (LAB). Mineral oil is classified as hazardous while LAB is classified as non-hazardous,” the report outlines. 

Approximately 177km of fluid-filled cables remain in service in Ireland under the control of ESB Networks. The cables were installed up until the mid-1980s when a transition was made to plastic cables which don’t require liquid installation. 

During the course of its investigation, the EPA found that ESB Networks had not consulted the relevant authority about 48 of the 68 leaks identified prior to June 2019.

The report notes that ESB also failed to screen the impact of fluid leaks, which had occurred since 1 April 2009. 

The EPA said it is satisfied with the approach and protocols now being implemented by ESB Networks to assess each leak and to engage with the relevant local authorities.

The EPA acknowledges that decommissioning of fluid filled cables can be a challenging process. but considers fluid filled cables that have a high occurrence of leakage and are in proximity to sensitive receptors should be prioritised for decommissioning.

The report concludes that the ESB has completed a preliminary assessment of each fluid-filled cable leak and submitted them the relevant local authorities.

Results of a site-specific investigation, which started last month and will identify the remediation to be carried out, will be submitted to relevant parties upon completion.