The hospitalisation of 11 workers following a major incident at Dublin’s new waste incinerator at Poolbeg forced the temporary closure of the plant within days of it coming into operation.
The incinerator is still only at the commissioning stage, but the timing of the incident undermines attempts to reassure local people about the safety of the plant.
According to Dublin Waste to Energy Ltd, “a small amount of lime” was inadvertently released late on Wednesday night inside the incinerator’s flue-gas treatment area during the commissioning and testing of the facility.
This was immediately converted into “a cloud” that rose through that section, where 30 construction workers were taking down scaffolding.
Eleven of the workers subsequently felt unwell and attended St Vincent’s University Hospital.
Nine were released on Thursday, but two were detained overnight. One of the two was reported to have respiratory problems but was getting better, while the other had sore eyes.
The company said it appeared from a preliminary examination that the release was due to a problem with a door seal at the bottom of a silo, through which 1 to 2 cubic metres of lime was discharged.
John Daly, managing director at Covanta Energy Ireland, indicated that what happened would be fully investigated, though he did not believe it was caused by human error.
The Health and Safety Authority (HSA) nonetheless has classified the incident as an “uncontrolled release” and a “dangerous occurrence”.
The HSA is conducting an investigation into what happened.
The Environmental Protection Agency (EPA) visited the plant and said that the "lime release was contained in the building and there was no loss of lime to the environment". It is satisfied there was no danger to the public .
Hydrated lime removes harmful chemicals from incinerator emissions before they reach the atmosphere, preventing pollution.
Exhaust gas
The exhaust gas generated from burning waste at the incinerator plant contains multiple harmful toxins and chemicals which need to be removed before the gas can be emitted .
Lime is particularly effective at trapping sulphur dioxide, while powdered activated carbon is used to absorb the worst forms of pollutants known as dioxins.
Lime in itself is toxic to humans, so such an incident would require full decontamination of those affected, including washing down and clothing disposal.
Dealing with 11 people in such circumstances would be regarded as a major incident in A&E.
According to Joe McCarthy, a Sandymount resident and expert in incineration, what occurred was “a major chemical incident” which was “worrying both from a scientific and process point of view”.
He questioned what he regarded as an unacceptable delay in deploying “the alarm mechanism” in alerting fire and health authorities.
The HSA says it was notified at 6am on Thursday of the incident, while it is understood that the EPA inspection of the plant only commenced mid-afternoon on the same day.
Covanta Energy Ireland has said the safety of its employees and contractors “is of utmost importance to Covanta”.