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Pest treatment using Nitrogen gas in the cultural heritage sector

Deterioration of cultural heritage objects from pest infestation is an ever-present problem. In recent decades, museums and cultural heritage institutions in Europe have turned away from potentially hazardous chemical pest control to an approach of Integrated Pest Management (IPM).

IPM uses, amongst a combination of other methods, anoxia or modified/controlled atmospheres for treatment with a very low oxygen atmosphere in a chamber (static) or tent (dynamic) with the aim to eliminate insect infestations. Different modified/controlled atmospheres include inert gases (for example nitrogen, helium, argon and carbon dioxide), where nitrogen is the most frequently used gas.

The displacement of atmospheric oxygen is a well-established method. There is no equivalent alternative in terms of preservation care and human health, for both staff and visitors of cultural heritage institutions. The procedure is included in the European Standard EN 16790:2016 Conservation of Cultural Heritage – Integrated Pest Management for the Protection of Cultural Heritage.

Many institutions have invested in their own treatment chambers for anoxic disinfestation, for both prophylactic and acute pest elimination. Unfortunately, with the extension of a mandatory registration of on-site generated nitrogen from September 2017 by REGULATION (EU) No 528/2012 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 22 May 2012, concerning the making available on the market and use of biocidal products (Biocidal Products Regulation, BPR), these facilities can no longer be operated legally.

As a result, the cultural heritage institutions are faced with the acute danger that cultural heritage may be damaged or irretrievably lost, or that traditional organo-chlorine biocides may experience an undeserved revival. Another alternative to nitrogen anoxia, carbon dioxide anoxia, is no longer supported on grounds of sustainability.

The nitrogen ban is not justified on grounds of health aspects. It is bad for the cultural heritage conservation community to have less choices for treatment interventions, with the anoxic treatment being among the most compatible with many materials and objects.

There are inconsistencies within the EU, for example the food industry has permission to use nitrogen gas for storage and preservation purposes, whereas the use of the same gas as a pest treatment is now not permitted.

Furthermore, different EU member states have interpreted the new directive in different ways, resulting in the institutions of at least two member states being permitted by their national authorities to continue to use nitrogen gas for pest treatment purposes, whereas in other member states the national authorities have been more restrictive in response to the new BPR.

In recent months, the confusion caused by the BPR, and the concern for cultural heritage at risk from pest damage, has created considerable debate at regional, national and international levels across the EU. A large number of professional heritage bodies from many different member states have published statements, lobbied national governments and written to EU institutions with the aim of repealing the classification of nitrogen as a biocidal active substance across the European Union.

On 12th March 2019, the International Council of Museums (ICOM) and the International Council on Monuments and Sites (ICOMOS) released a joint statement and called for the immediate repeal of the classification of nitrogen as a biocidal active substance for cultural heritage preservation applications across the EU (https://icom.museum/en/news/joint-statement-call-icom-icomos/). Jointly with our parent body, ICOM UK advocate for a solution in which the use of nitrogen for this specific purpose in cultural heritage preservation is ratified for the entire European Union, based on a repeal of the classification of nitrogen as a biocidal active substance.

ICOM UK