The megalithic passage graves at Newgrange, Knowth and Dowth could be damaged by "the polluting effect" of emissions from an incinerator proposed by Indaver Ireland for Co Meath, according to Dr George Eoghan, the world's leading expert on the complex.
In a handwritten statement to the Environmental Protection Agency (EPA) hearing into objections to granting a waste licence for the incinerator, Dr Eoghan said he was particularly concerned about the megalithic art at the three tombs which "constitutes Europe's greatest assemblage, a virtual open-air gallery".
The incinerator is proposed for a greenfield site at Carranstown outside the footprint of the Boyne Valley.
The role of the EPA to enforce breaches of waste licences was questioned yesterday by Brian Hanratty, of the No Incineration Alliance (NIA). He said "it is not effective in protecting the public's interest from both a health and environmental perspective".
The requirement for companies to carry out "on-going monitoring of their own operations" must be called into question.
Conor Jones, for Indaver Ireland, said there would be €1 million worth of equipment in an emissions-monitoring laboratory. While there would be continuous dust monitoring, there was no technology to measure for dust particles known as PM 10 and 2.5. The hearing has already been told these are pollutants linked to respiratory problems.
He also said there would not be continuous monitoring of dioxins, but it would be sampled over a period of a fortnight, and the data sent to a UK laboratory.
Cross-examined by the NIA, he said it could be two weeks before results would be known, but if there was a breach of the dioxin level the plant would be immediately shut down.
He said a specialist Turn Key contractor would be appointed to construct the plant. This would be built "to a performance specification laid down by Indaver. This contractor will be managed by our Belgian colleagues who have experience of construction of these facilities."
This process was described by Pat O'Brien of the NIA as "a pig in a poke, and there should be technical experts here for Indaver to answer specific questions from the community".