Shell E&P Ireland has said it is conducting an internal investigation, following the inadvertent cutting of a gas pipe at the Corrib gas terminal earlier this month.
The incident, which occurred during work on water pipes at the terminal site in north Mayo, resulted in nitrogen being released into the atmosphere.
As a precaution, all nitrogen was “vented off”, according to the company. The Ballinaboy terminal built to refine gas from the Corrib gas field is not yet active, as work is still continuing on the last section of the project – the onshore pipeline.
However, low pressure nitrogen has been pumped through pipes laid at the terminal to prevent corrosion.
The company has been criticised by the campaign group Shell to Sea for failing to make the incident public after it occurred on April 8th. It came to light when a resident alerted Midwest Radio.
The multinational told the radio station the incident posed “no danger to the environment”, and said it was investigating the circumstances.
It said it occurred during ongoing work to replace water surface pipes at the site, and that a supervisor was alerted.
The Environmental Protection Agency (EPA) told The Irish Times it had not been informed, but that there was no obligation on the company to do so as "licensable activities" had not actually started.
Mayo county secretary John Condon said the authority was "aware of a minor incident" during maintenance, which involved "cutting a pipe which then involved nitrogen gas releasing into the atmosphere".
However, as there is normally over 78 per cent nitrogen in the atmosphere, it was not a cause for concern, he said.
Mr Condon said it would be reported “in the normal way” to the project monitoring committee, which involves representatives of statutory agencies, the company and community representatives.
He said Shell did provide the local authority with information on the incident, but could not state when this occurred.
Shell to Sea spokeswoman Maura Harrington said “Shell, despite all their talk of being ‘good neighbours’, said nothing to anyone” until the radio station was alerted.