The Environmental Protection Agency (EPA) has approved an operating licence for the Corrib gas refinery in north Mayo.
The agency has also said that its director, Dr Mary Kelly, did not participate in the decision, which was taken at board level.
This was due to the fact Dr Kelly had, in a previous post, appeared on a promotional video for the Corrib gas project, made by former developers Enterprise Energy Ireland (EEI).
This issue had been raised by objectors at an oral hearing held by the agency on the licence application earlier this year.
Dr Kelly had been speaking on behalf of employers' group Ibec in the 24-minute film, presented by broadcaster Alan Cantwell and entitled Energy Report: Corrib Gas.
A spokeswoman stressed that this was before she took up her post with the agency.
The successful Shell E&P Ireland application for an integrated pollution prevention control (IPPC) licence is subject to 90 conditions. The application received preliminary approval from the EPA last January.
The decision has been welcomed by Shell E&P Ireland and its Corrib gas partners as a "significant milestone". The agency says that the approval followed an "exhaustive examination" of the application, which was submitted by Shell on December 8th, 2004.
Further information was sought from the applicant and the application was completed on October 12th, 2006. A proposed approval was issued on January 26th last and 13 objections, including one submitted by Shell E&P Ireland, were considered at a 12-day oral hearing which sat in Belmullet, Co Mayo, on dates from April 16th to May 9th last.
Other objectors included An Taisce, local parish priest Fr Michael Nallen and individual members of the Shell to Sea group.
The EPA board noted that cold venting of gas at the refinery was an issue of "major concern" to local residents, but said that it accepted the chairman's recommendation that this was the "best environmental option in the circumstances, due to the small volume of gas released".
It also said that it accepted recommendations in its chairman's report to strengthen controls relating to the risk of pollution to Carrowmore lake, supplying drinking water to 10,000 people.
The agency has agreed to increase the monitoring of marine waters around the discharge point for the refinery and to enhance the level of noise monitoring at "nearby noise-sensitive locations" and to provide greater control of methanol releases.
The agency said that in addition to imposing "significant controls" on the refinery's operation, a series of monitoring and reporting requirements will "provide the EPA and the general public with detailed insight into the environmental performance of the installation".
The agency says that it will carry out its own independent inspection and monitoring of emissions, as well as a detailed annual audit of the refinery's operations, and the public will have access to all monitoring results and reports.
