The first of three legal challenges to plans for a new €329m runway at Dublin Airport has opened at the High Court.
The proceedings arise over the proposed development of the 3,110 metre runway, located on 261 hectares north and north west of the airport terminal building.
The second runway has been deemed vital to proposals to turn the airport into an international hub.
All three actions are to be heard in sequence by Mr Justice Max Barrett.
The first to be heard has been brought by the St Margaret's Concerned Residents Group - of which the individual residents are members - is against the Dublin Airport Authority (DAA).
The residents claim certain pre-construction works carried out in December of last year on the proposed new runway by the DAA amounts to unauthorised development.
The residents claim the development was carried out in breach of a condition of the planning permission granted by An Bord Pleanala in 2007 allowing the DAA construct the runway.
John Rogers SC, for the residents, said it is their case the DAA failed to adhere to a planning condition covering how waste from the site of the new runway is to be dealt with during the construction phase.
A waste management plan had to be submitted by the contractor and approved by Fingal County Council "prior to the commencement of the development," counsel said.
This was not done and there had been non compliance by the DAA in relation to the planning permission.
Counsel said works commenced on the site of the proposed runway in December 2016, which involved the demolition and removal of buildings, including a fire training facility at the airport, from the lands.
However the required waste management plan was not submitted to the local authority Fingal Co Council until February 2017 after his client's solicitors had raised the matter.
Counsel said that some of the items removed from lands that are adjoining the residents properties contained toxic material including asbestos.
It was not accepted that the breach of a planning condition put in to protect his client's interests was immaterial, counsel said.
The DAA opposes the action and argues that no unauthorised development has occurred. Brian Kennedy SC, for the DAA, said that due to an error, the waste management plan was not submitted to the local authority before works began.
However the problem had been rectified with the submission of the relevant document before the residents began their legal action.
Counsel said the action was "unnecessary".
While the waste management plan had inadvertently not been included in time it had been adhered to since works had began.
The error did not give DAA any advantage and had in fact caused it "a world of pain" counsel said.
Counsel added that if the court did find the works were unauthorised development then the court should use its discretion not to grant any of the orders sought by the residents.
The hearing of that case continues and is expected to conclude on Wednesday.
The second of the three challenges has been brought by 22 individual residents - most with addresses at Kilreesk Lane, St Margaret's, Co Dublin while the third action has been brought by Friends of the Irish Environment.
They allege the development is illegal and that Fingal Council failed to consider or address their concerns about its effect on their homes and lands.
The environmental group's action has been brought on grounds including the decision to grant planning permission is not in compliance with various EU directives such as the Habitats Directive as well as the 2000 Planning and Development Act and is unlawful.
The group also argues that the decision will result in additional greenhouse gas emissions which will increase the pace of climate change.
Those two cases have been brought against Fingal County Council and the State, with DublinAirport Authority plc as a notice party.