Tens of thousands of people were without power when the pylon fell over in June. Photo: Supplied / Top Energy
The Electricity Authority is calling for a law change that would allow it to compel companies to provide information in future investigations, such as that into the downed pylon that cut power to Northland earlier this year.
In Wednesday's report on the toppled pylon, the Authority claims both maintenance contractor Omexom and national grid operator Transpower withheld what it described as "key documents".
That included Omexom's draft incident cause report, and Transpower's interviews with Omexom staff.
Legal privilege was cited as the reason for denying access to certain documents.
The report, based on an investigation led by lawyer Sarah Sinclair, said the review's challenges had "highlighted the importance of transparency and full access to all relevant information".
"While the Authority received and reviewed a significant amount of information provided by Transpower and Omexom, the review would have benefited from greater access to key documents. Specifically, legal privilege was claimed by Omexom for its draft Incident Cause Analysis Method (ICAM) report into the event, and by Transpower for interviews held with the Omexom maintenance crew, in their entirety. This has limited our ability to get a fuller understanding of the events on the day and the wider considerations which impacted this event," the report stated.
Under the current law, the Electricity Authority could not compel Omexom to provide information because unlike, say, a power company, it was not "an industry participant".
During a press conference on Wednesday, Sinclair said the investigators had been unable to speak to any of the workers on site when the pylon fell.
The report stated Omexom management had met investigators and answered questions, but the lack of access to the ICAM report - which addressed the root causes and contributing factors in the pylon collapse - had been "a material limitation".
One of the report's 26 recommendations is to update the law so the Authority has the power to require information from "non-participants", and the penalties to ensure compliance.
However, a Transpower spokesperson said the company did not withhold any documents or material under its legal privilege - and was legally unable to release documents it had received from Omexom.
"The interviews with Omexom's staff were held on a strictly confidential basis. They were attended by Omexom's lawyers, and Omexom asserted common interest privilege over the transcripts and notes. Omexom were invited on multiple occasions to lift that privilege and declined to do so. As the legal privilege was Omexom's, Transpower could not release or provide the material to the Authority," the spokesperson said.
An Omexom spokesperson said after an event such as the pylon collapse, a great deal of information needed to be gathered over a period of time.
"It is not unusual in a situation like this that information and recommendations made during these processes are subject to legal privilege," the spokesperson said.
Legal privilege is a term for the protection of confidential communication between a lawyer and a client, in particular when that communication has the purpose of obtaining legal advice.