As intense wildfires become more frequent and extensive globally, should we pay more attention to the chemicals routinely used as retardants?

An air tanker drops retardant as the Lake Fire burns in the Angeles National Forest north of Santa Clarita, Calif., on Thursday, Aug. 13, 2020. (AP Photo/Noah Berger)

2020 seems to have been a particularly bad year for wildfires globally. Major fires that commenced in Australia in 2019 continued into the first few months of 2020. They were followed by wild (or biomass) fires in many other parts of the world, from the Amazon to the Arctic and from central Africa to California, and other states in western/northwestern US. Wildfires have a multiple of causes, of course, but climate conditions are often a major contributing factor. Perhaps unsurprisingly, an August 2020 paper in the journal Environmental Research Letters, available here, finds climate change to be important in increasing the likelihood of extreme late summer/autumn wildfire conditions across California. The authors note that a cocktail of environmental conditions (high temperatures, low rainfall, strong winds) have enabled the ignition and spread of wildfires. They use climate models to project future conditions, and find that continued climate change will further lengthen the period during which extreme fire weather occurs, and hence the most devastating wildfires (assuming there is still biomass left to burn!).

Is this how the world ends?

Given that major wildfires are perhaps even more likely, rather than less, in coming years – as a result of climate change but also as humans and their sources of ignition penetrate deeper into forested and peat lands, now is probably a good time to evaluate the effectiveness of our response. Here I would like to focus, in particular, on the chemicals that are used to limit the spread or reduce the intensive of wildfires ~ fire suppressant and retardant chemicals, in other words. These are the often brightly coloured substances that get air-dropped on and around wildfires – they are to fighting wildfires what chemical dispersants are to dealing with oil spills at sea. Just as we have begun to question the efficacy of chemical dispersants when dealing with a major oil spill it is probably useful to enquire about fire suppressant and retardant chemicals, and in particular whether they do more harm than good.

There are several types of fire suppressant (generally applied to a fire to reduce its intensity) and retardant (used to reduce the chances of a fire starting or spreading once started) chemicals. Fire suppressants generally reduce the temperature of the fire – water sprayed onto burning vegetation is an example, as are chemical foams. Foams are wetting agents that allow water to penetrate a surface more effectively, thereby allowing its more efficient use in suppressing a fire.

Fire retardants (e.g. Phos-Chek) are most often used in the creation of fire breaks – their application is aimed at reducing the combustibility of vegetation ahead (i.e. in front) of an advancing fire. They are therefore designed to persist in the environment rather than to degrade immediately. The most common retardants are a combination of water and either ammonium sulfate [(NH4)2SO4] or diammonium phosphate [(NH4)2HPO4] mixed with additives to thicken, reduce spoilage during storage and colour the liquid. The latter give fire retardants their bright colours – so that it is possible to see which parts of the landscape have already been treated, but also (I guess) to look good on the TV …. Retardants also include other elements to help reduce combustibility, including antimony, chlorine, bromine, boron. Chlorine and bromine are used in what are known as “halogenated retardants”.

A plane drops fire retardant on a wildfire in Fallbrook, Calif. (AP Photo/Gregory Bull)

Generally retardants are regarded as being non-toxic to humans and large mammals, at least in low concentrations. However, their toxicity to aquatic life, even at low concentrations, has long been known (e.g. Dietrich, 2013). Although retardants are meant for terrestrial use (spraying on forest and other combustible biomass) they can end up being washed into or inadvertently sprayed over aquatic ecosystems. Further, the toxicity of some of the chemicals used may be enhanced by the heat of, or through mixing with emissions from, the wildfire. At high temperatures, some halogenated retardants can form extremely toxic dioxins, for example.

And then there are the environmental effects of spraying ammonium sulfate and diammonium phosphate over large areas of vegetation and soil. Both are ammonium-based fertlizers, and therefore likely to result in environmental eutrophication and acidification. Ironically, depositing large amounts of fertilizer is likely to boost productivity in vegetation that survives the fire – resulting in increased loadings of highly-combustible litter, potentially adding to the intensity of any burn during the next fire-season ….

Given the current extent and intensity of wildfires and the likelihood that conditions that predispose biomass to burning will become more extensive, frequent and intense in coming years, chucking chemicals that only add to environmental pollution and its harmful effects at the problem seems neither desirable nor sustainable.

 

44 thoughts on “As intense wildfires become more frequent and extensive globally, should we pay more attention to the chemicals routinely used as retardants?

  1. I’m not that much online reader but your site is really nice and would appreciate the efforts you made to create this blog. I’ll bookmark this site for more interesting blogs in future. very much informative post.

    홀덤

  2. Thanks for this incredible blog post! I am truly grateful for the valuable information and insights you’ve shared. Your writing style is engaging and informative, keeping me hooked from start to finish. The depth of research and expertise you’ve put into this article is evident, and it’s commendable. The practical tips and advice you’ve provided are incredibly helpful and actionable. I can’t thank you enough for taking the time to create such high-quality content. It’s clear that you have a passion for the subject, and it shines through in your writing. I’m eagerly looking forward to reading more of your blog posts.
    Abogado de Violencia Doméstica de Nueva Jersey

  3. Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters here! It’s always nice when you can not only be informed, but also entertained! Boise troubled teen program

  4. Very useful post. This is my first time i visit here. I found so many interesting stuff in your blog especially its discussion. Really its great article. Keep it up. toto wayang

  5. This is such a great resource that you are providing and you give it away for free. I love seeing blog that understand the value. Im glad to have found this post as its such an interesting one! I am always on the lookout for quality posts and articles so i suppose im lucky to have found this! I hope you will be adding more in the future…Drake Leaked Video

  6. Very informative post! There is a lot of information here that can help any business get started with a successful social networking campaign. Agen108

  7. Thank you because you have been willing to share information with us. we will always appreciate all you have done here because I know you are very concerned with our. Liga8et Slot

  8. Very informative post! There is a lot of information here that can help any business get started with a successful social networking campaign. alexistogel

  9. Thanks for a very interesting blog. What else may I get that kind of info written in such a perfect approach? I’ve a undertaking that I am simply now operating on, and I have been at the look out for such info. medical device housing

  10. Wow, What a Excellent post. I really found this to much informatics. It is what i was searching for.I would like to suggest you that please keep sharing such type of info.Thanks alexistogel

  11. This is my first time i visit here. I found so many interesting stuff in your blog especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here keep up the good work Agen108

  12. I was surfing the Internet for information and came across your blog. I am impressed by the information you have on this blog. It shows how well you understand this subject. alexistogel

  13. You make so many great points here that I read your article a couple of times. Your views are in accordance with my own for the most part. This is great content for your readers. alexistogel

  14. Its a great pleasure reading your post.Its full of information I am looking for and I love to post a comment that “The content of your post is awesome” Great work. alexistogel

  15. I found so many interesting stuff in your blog especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here! keep up the good work… exototo slot

  16. Hello I am so delighted I located your blog, I really located you by mistake, while I was watching on google for something else, Anyways I am here now and could just like to say thank for a tremendous post and a all round entertaining website. Please do keep up the great work. alexistogel

  17. Thanks for the nice blog. It was very useful for me. I’m happy I found this blog. Thank you for sharing with us,I too always learn something new from your post. alexistogel

  18. What a fantabulous post this has been. Never seen this kind of useful post. I am grateful to you and expect more number of posts like these. Thank you very much. alexistogel

  19. I am very enjoyed for this blog. Its an informative topic. It help me very much to solve some problems. Its opportunity are so fantastic and working style so speedy. hoki108

  20. Hello I am so delighted I located your blog, I really located you by mistake, while I was watching on google for something else, Anyways I am here now and could just like to say thank for a tremendous post and a all round entertaining website. Please do keep up the great work. alexistogel

  21. I am very enjoyed for this blog. Its an informative topic. It help me very much to solve some problems. Its opportunity are so fantastic and working style so speedy. alexistogel

  22. Hello I am so delighted I located your blog, I really located you by mistake, while I was watching on google for something else, Anyways I am here now and could just like to say thank for a tremendous post and a all round entertaining website. Please do keep up the great work. alexistogel

  23. I am very enjoyed for this blog. Its an informative topic. It help me very much to solve some problems. Its opportunity are so fantastic and working style so speedy. alexistogel login

  24. Wow! Such an amazing and helpful post this is. I really really love it. It’s so good and so awesome. I am just amazed. I hope that you continue to do your work like this in the future also alexistogel login

  25. You make so many great points here that I read your article a couple of times. Your views are in accordance with my own for the most part. This is great content for your readers. INSTASLOT88

Leave a Reply

Your email address will not be published. Required fields are marked *