Sir, - Tom Prendeville of Earthwatch/Friends of the Earth (October 12th) disingenuously conflates a number of issues to present a very misleading picture, and along the way makes a wholly unfounded allegation against Noel Dempsey, Minister for the Environment and Local Government.
He seeks to link the Government's well-founded opposition to the proposed opening of a new MOX nuclear fuel reprocessing facility at Sellafield with proposals for the thermal treatment of household and commercial waste, a waste management option which is employed throughout the developed world. This is plainly nonsense.
Mr Dempsey is accused of "paving the political path" for the development by a private company, Indaver Ireland Ltd, of a municipal waste incinerator at Carranstown, Co Meath. This is patent nonsense. It is open to any individual or company to initiate such a project, which must then go through the normal independent planning and environmental licensing systems, in which the Minister has no function.
He maintains that all incineration residues are "dioxin-laden, hazardous, toxic". This is not the case. The main solid residues from incineration comprise "bottom ash" (from the combustion chamber) and "fly ash" (from the flue-gas filtration process). Bottom ash amounts to about 20 per cent by weight of the original waste intake and is classified by the EU as a non-hazardous waste. Recyclable metals can be extracted from it, it can be used in road construction and incorporated into cement, or it can be disposed of in landfills.
Fly ash amounts to about 5 per cent of the original waste intake. It can contain heavy metals and dioxins and is classified as a hazardous waste that requires disposal in a special landfill. This ash can be rendered inert by being transformed into a glass-like material, or encased in cement, prior to disposal. The management and disposal of ash residues from an incinerator would be controlled by the EPA.
Mr Prendeville refers to two cases in the UK where hazardous fly ash was illegally disposed of on allotments and incorporated into building blocks. These cases reflect industry malpractice and regulatory failure. They do not constitute an argument against thermal treatment of waste as a valid waste management option.
The issue of dioxins must be put in perspective. Most combustion processes (including vehicle engines, domestic fires, wood and stubble burning and cigarettes) generate dioxins. They are to be found in all environmental media - air, water, sediments and soil.
Banning all activities or processes which may generate dioxins is clearly not practicable. The key issue is whether dioxin emissions from a given process or activity represent a significant risk to human health or the environment.
The International Agency for Research on Cancer, an agency of the World Health Organisation, has classified one dioxin compound as a known human carcinogen.
However, the WHO states that there is a level of exposure below which cancer risk from dioxin would be negligible.
Clearly, because of their potential toxic effects, dioxin emissions must be strictly controlled and minimised, and this is the purpose of the stringent emission standards and controls currently applicable in Ireland. The EPA applies an EU flue gas emission limit value of 0.1 nanogram per cubic metre for dioxins - this is one ten thousand millionth of a gram per cubic metre of gas emitted. In practice, modern emission control technology can achieve 10 to 20 per cent of this limit value.
The information available to the Minister is that emissions from proposed new thermal treatment facilities for waste, employing modern technologies and subject to compliance with strict environmental and operating standards, should not have any appreciable environmental impact or contribute significantly to background levels of dioxins.
However, in light of public concerns on this issue, the Minister has requested the independent Health Research Board to commission a study of all available international information and research and to provide an objective risk assessment of the impact on public health and the environment of emissions from thermal treatment and landfill facilities operated to modern standards.
The results of this study will be available in the first quarter of 2002 and will be published.
Incidentally, the dioxin contamination found in poultry and eggs in Belgium in 1999, to which Mr Prendeville referred, is attributed to animal feed which had been contaminated with a mineral oil containing dioxins. There was no link with waste incineration. - Yours etc.,
Ronnie Devlin, Press Officer, Department of the Environment and Local Government, Custom House, Dublin 1.