Toxic Heavy Metals Found in Aerial Fire Retardant

A new peer-reviewed study from USC’s Department of Civil and Environmental Engineering finds alarmingly high levels of toxic metals in Phos-Chek fire retardant.

Bottom-line conclusion: “Long-term fire retardants contained concentrations of toxic metals (V, Cr, Mn, Cu, As, Cd, Sb, Ba, Tl, and Pb) 4−2,880 times greater than drinking water regulatory limits, and potentially greater than some aquatic toxicity thresholds when released into the environment.”

This is the first publicly available chemical analysis of Phos-Chek’s toxic metals. If the Forest Service has conducted such an analysis, it has never disclosed the results. Nor has the Forest Service ever assessed the effects of dumping these heavy metals hither and yon on our national forests.

17 thoughts on “Toxic Heavy Metals Found in Aerial Fire Retardant”

  1. I would not be “alarmingly” concerned as much for nano-concentrations of chemicals as I would be seeing a wildfire headed toward my investment properties and not have retardant to use!

    Just saying…..

    Reply
      • It depends; good forest management, coupled with effective initial attack with the use of all resources available – including retardant, is an almost guarantee of success! Dropping retardant just for the sake of seeing it on tv is not only a waste of taxpayers money but also builds false expectations from a mostly uneducated (on wildland fire control) public.

        My fire experience started in 1971 and covers most of the lower 48, ranging from 0.1 acres to over 500,00! I’ve seen it (retardant) work, and I’ve seen it not, so don’t mix me up with those who do not know the difference…..

        Reply
        • Things are changing now…..fuels treatments don’t really work in many of the super hot weather-driven fires, and it’s just hard to stop those kinds of fires. Seems like often they just stop when the weather changes, winds die down and/or rain comes. Often firefighters manage to drive the fire away from homes though. But at this point I think there are no guarantees of success.

          Like anything, it should be a cost/benefit analysis, costs meaning social, health and environmental costs as well as monetary costs. So we need to know what toxics remain in the environment after retardants are used, and balance it with some kind of estimate of how much such retardants have slowed down any particular fire.

          Reply
      • The amount of heavy metals in Phos-chek sounds bad, but compared to what? Wildfires themselves emit heavy metals, and of course particulate matter that also is s significant health threat. Example:

        “A new California Air Resources Board (CARB) analysis of air quality data collected during the deadly Camp Fire sheds new light on exactly what was in the thick smoke that blanketed much of Northern California for two weeks in November 2018. The document, published today, shows smoke produced from the Camp Fire exposed Californians to dangerous levels of particulate matter and contained concerning levels of toxic metal contaminants, including lead, which spiked for about 24 hours.”
        https://ww2.arb.ca.gov/news/new-analysis-shows-spikes-metal-contaminants-including-lead-2018-camp-fire-wildfire-smoke

        Another example, from Stanford University:

        Published Dec. 12 in Nature Communications, the research documents high levels of a hazardous form of the metal chromium at wildfire sites with chromium-rich soils and certain kinds of vegetation compared to adjacent unburned sites. Known as hexavalent chromium or chromium 6, this is the same toxin made notorious by the 2000 film Erin Brockovich.

        “Our study suggests far more attention should be paid to wildfire-modified chromium, and we presume additional metals as well, to more thoroughly characterize the overall threats wildfires pose to human health,” said lead study author Alandra Lopez, a postdoctoral scholar in Earth system science at the Stanford Doerr School of Sustainability
        https://news.stanford.edu/stories/2023/12/wildfires-leave-trail-toxic-metal-soil

        Reply
        • Steve — your straw man assumes that retardant prevents wildfires. There is no credible (i.e., scientific) evidence that retardant affects any measurable ignition outcome, e.g., acres burned or homes destroyed.

          The available evidence does not paint a hopeful picture. In the only study to assess retardant use in initial attack, “containment rates of fires associated with LAT [large air tanker] use are low; 75% of all IA [initial attack] drops were on fires that escaped IA containment efforts.” This 25% success rate when large air tankers (which only carry retardant) are utilized in initial attack compares poorly with the 98% success rate enjoyed by the Forest Service overall.

          Half the retardant used nationally is dumped in California. But for where California has been paved with parking lots and pink hotels, the state’s landscape burns with robust enthusiasm. If retardant moved the California fire needle measurably, Paradise would still be standing.

          Reply
          • Andy, I intended only to provide context, not debate the use and/or effectiveness on retardants. I’d like to see a larger study that includes retardants applied by all aircraft.

            FWIW, I have been on wildfires there the fire was stopped or significantly slowed by retardant – black right up to the red.

            Reply
      • All inclusive from personal property, real property, timber values and human life! Not much of a trade off; retardant has been used for at least 60 years I know of. Folks are out there chasing ghosts when there are many other issues that are truly health concerns. For anyone wanting to get rid of all retardant, it’s a pretty petty and whimsical excuse to base it on human health! Where it is needed, it is a life saver – both public and firefighter, if that matters to anyone.

        I used “investment property” to reflect all values associated with life; life itself is an investment. For anyone who says retardant doesn’t work has not been of fires where it truly does perform as advertised. The delineation of watersheds, avoidance zones and better monitoring has quelled most of the concerns with its use; time to dream up something new…..

        Reply
  2. In addressing the effects of retardants containing magnesium choride, the FS said in a 2022 DSEIS:

    “However, the required protective measures (avoidance areas) would be adequate to prevent water quality degradation due to use of retardant products containing MgCl, except in the event of an accidental spill or direct application.”

    Available here: https://cdxapps.epa.gov/cdx-enepa-II/public/action/eis/details?eisId=356569 [see pdf p.37 of the DSEIS]

    Say what one will about this assertion (and I can guess what Andy would say – indeed, probably has said), I suspect the agency would make similar arguments about any metals present in fire retardants. (I’ll confine my own observation to noting that the last clause of the quote is doing a lot of work.) And I would also guess the agency used a similar rationale for not having carried out a chemical analysis of any fire retardant (I agree that it is unlikely that this ever occurred).

    Reply
  3. Unlike Jim Z I DO NOT have extensive fire experience… but I know many who are as well experienced. To a person, they say that retardant MAY be effective in IA, but (as in Andys’ study cited above) if lost at that stage, retardant becomes pretty worthless in STOPPING fires. Steering? Maybe. At about $30k a shot, it’s a VERY expensive “show”. I don’t think there has ever been a true reckoning about cost/benefit, as suppression costs skyrocket. Makes good news footage though.

    Reply
    • Nowhere did I say retardant would stop a fire, it takes boots on the ground to do that! Retardant is a tool to use in suppression, just like water, a Pulaski or someone who has the gumption to know how. It is expensive and used too much for show. Cost effective? 🤣🤣. Since when has that been a factor since the 1980’s…..

      However, it can and does modify fire behavior to allow, in some cases, direct suppression tactics where other values at risk begin to rare their heads. Retardant is much more effective in the South and East due to properly, aggressively managed forests, for the most part, and lower radiant outputs of most fires.

      To take away aerial retardant will certainly change the profile of wildfire effects, and those fewer folks who actually sweat on the line will become few and far between….

      Reply
  4. I don’t find “cost effective” to be a humorous topic at all, but I agree it hasn’t been a factor. I’m arguing for more judicious, thoughtful use of retardant. It has a place.

    Reply
    • As am I; on that we both agree! I used humor to show the lack of sensibility in all things fire. I left the FS in 1983, coming back in in 2001, didn’t even resemble the Agency I left. Stovepiped fire organization was the biggest change.

      I watched the early VLATs drop on the Wallow Fire, all because John McCain wanted to see it. The fire was almost out at that point but it made great film (film 🤣) for the Phoenix stations…. I think they were $75,000/ load at that time. We had 17 helicopters at the local airport for support. 110 million $ suppression costs and 32 million $ BAER.

      Reply
    • “I’m arguing for more judicious, thoughtful use of retardant.”
      Yes, there’s pretty much no black or white answers these days, and it all boils down to being conservative with interventions and only applying them when a well-considered risk/benefit analysis clearly justifies it. So often interventions backfire, one way or another.

      Reply
      • Some (though certainly all) of the disputes in this thread relate to the effectiveness (or not) of retardant drops in extended attack. This RMRS cast some (though not conclusive) doubt on extended attack retardant use:

        https://research.fs.usda.gov/treesearch/50972

        Here is some key language from the abstract (emphasis added):

        Additionally, we show that use is generally within guidelines for operational application (aircraft speed and height above ground level) *and often outside of environmental guidelines suggestive of conditions conducive for most effective use, including drop timing with respect to response phase (initial attack v. extended attack), terrain, fuels and time of day.* Finally, our results suggest that *proximity to human populations plays a role* in whether airtankers are dispatched, suggesting that prioritisation of community protection is an important consideration. This work advances efforts to understand the economic effectiveness of aviation use in federal fire suppression.

        A (not the) point of this report was to assess whether CNN drops were a thing. My read of the very careful conclusion of the authors is ‘yeah, kinda.’

        Reply
        • Although I wasn’t in fire there, I understood that our Forest had a ‘standard dispatch’ on new fires. There’s some lag time, when an IC can cancel some of the mobilizing resources, if not needed. Usually, it seemed like an air tanker was automatically dispatched.

          Reply

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