Fumigation: an ‘inconvenient truth’

Adnan Uzunovic explains why Governments worldwide must take action now to replace methyl bromide and sulfuryl fluoride with an environmentally sustainable alternative.

Al Gore coined the term an ‘inconvenient truth’ in his eponymous 2006 documentary.

It is an apt description of the practice of fumigation around the world. In an era of global trade in forestry products, where invasive pests can be inadvertently imported, it is an essential activity to ensure biosecurity. Fumigators are a critical line of defence against such pests, which have the potential to harm native plant life, affect economies, and hinder the environmental functions that healthy forests provide.

The threats and associated costs are real – in 2018, over six million acres of trees died because of forest pests or disease. The maximum potential economic impact to the US from potential imports of the Asian Longhorn Beetle is estimated to be in the order of $669 billion through tree mortality. Suppressing a 1996 infestation of the pest in New York State cost local authorities more than $4 million.

However, the chemicals traditionally used as fumigants to protect our natural environment, methyl bromide and sulfuryl fluoride, are in fact incredibly harmful to our planet.

Methyl bromide is an ozone-depleting substance, more than 50 times as reactive in ozone depletion as bromine. While the United Nations agreed to phase it out by 2015 through the Montreal[1] protocol agreement, it is still readily used by many countries under agreed quarantine exemptions, while recent data alarmingly suggests growing use in Australia, China and India.

Governments seeking to replace methyl bromide (the EU, for example, has banned its use within its borders) increasingly turn to sulfuryl fluoride. However, as recent assessments demonstrate, sulfuryl fluoride is a potent synthetic greenhouse gas, dubbed a “climate killer” by the scientific community. Every kilogram of sulfuryl fluoride used has a 100-year Global Warming Potential of over 4 tonnes of CO₂. Such countries are, under the auspices of regulatory authorities, simply swapping one environmentally destructive chemical for another.

Despite the significant environmental harms they cause, both methyl bromide and sulfuryl fluoride fall out of the regulatory rubric: neither chemical is part of the Kyoto Protocol or the Paris Agreement, so there are no global targets to reduce emissions.

As a result, around 11,000 tonnes of methyl bromide[2] and 3000 tonnes of sulfuryl fluoride continue to be used every year despite their detrimental impacts on the atmosphere. Amid the ever-worsening climate crisis, the continued reliance of both chemicals is unsustainable. 

An alternative

Fortunately, a sustainable alternative, which has gone through extensive scrutiny and research, is available. Ethanedinitrile (or EDN) is currently the only economically viable and environmentally benign alternative to methyl bromide and sulfuryl fluoride which is also highly efficacious against numerous pest types. Its use is slowly growing around the world. 

Yet the biggest barrier to the introduction of alternatives to methyl bromide and sulfuryl fluoride can be posed by regulators and Governments themselves. New products such as EDN can face an incredibly high bar for introduction, even when supported by extensive and reliable data, and a lack of agreement on common evaluation criteria creates an ever-growing web of divergent regulatory pathways.

Where such data and research is available, Governments and regulators should follow the facts. We currently have a situation where it can be easier to continue to permit – and sometimes even require – the use of chemicals which are known to be incredibly harmful for both people and planet, rather than introduce new environmentally sustainable alternatives. This must be urgently addressed.

There is in fact more and better data on the efficacy and environmental profile of EDN than methyl bromide or sulfuryl fluoride when they were first introduced. Regulators should follow the facts.

Fortunately, some do. In the Asia-Pacific region, EDN is used in both South Korea and Malaysia, and it is used under emergency permit in the Czech Republic.

From July this year, New Zealand permitted the importation and use of EDN, in a move that was welcomed by the country’s forestry sector. In October, Turkey also registered EDN for use on imported logs.

While these countries should be lauded for their efforts, international bodies and Governments elsewhere must act faster to safeguard both continued trade in essential commodities as well as the environment. Speeding up the regulatory process for those seeking to register and use alternative fumigants with a stronger environmental profile and backed by extensive and reliable datasets, such as EDN, would be a start on this journey.

For too long, fumigation has been a regulatory blind spot for many governments, and it has never been more crucial that we transition away to alternative products that do not damage the atmosphere. Bringing in new and sustainable alternatives should not be harder than phasing out products we know are harmful to our planet.

Protecting our natural environment is important, but it should not cost the earth.

Adnan Uzunovic (pictured below) has been senior researcher for more than 20 years at the Canadian Wood Research Institute and is an adjunct professor at the Department of Forest and Conservation Sciences at the University of British Columbia. He can be contacted at: [email protected]