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2019 Unified Wine and Grape Symposium


Bright red aerial fire retardant may be a lot more toxic than manufacturer says. Scientific Study Casts Serious Doubt on Validity of Toxicity Documents

Wine Industry Insight’s October 24 article — Phos-Chek: Deadly to salmon, cautions for wine grapes, sketchy data on human effects, confusion among public officials — raised scientific questions about the actual toxicity of the fire retardant that played such a key role in controlling the historically damaging wine country wildfires this month.


In that article, we noted that the only peer-reviewed, published scientific study found during an extensive search of the scientific literature is a 2014 paper: “Toxicity of PHOS-CHEK LC-95A and 259F fire retardants to ocean- and stream-type Chinook salmon and their potential to recover before seawater entry”. That study found that small Phos-Chek concentrations that are a fraction of that used in application will kill 50% of Chinook salmon.


  • “LC-95A is lethal to 50% of Chinook salmon at 0.23% of the applied concentration.”
  • “259F is lethal to 50% of Chinook salmon at 0.09% of the applied concentration.”


Adding to the confusion of determining the safety of the material used in Napa and Sonoma Counties is the fact that there are many different formulations of Phos-Chek. Most share some form of fertilizer chemicals, and all of contain “trade secret” ingredients which are not disclosed.


Concealing chemicals that may be dangerous is a widespread — and currently legal — practice in documents filed by companies to comply with U.S. government regulation. (See Secret Chemicals: What The Government Won’t Tell You, Can Kill for more).


The salmon study, cited above, is based on LC-95A and 259F formulations of Phos-Chek and not MVP-Fx as used in Napa. Because the information in the MVP-Fx data sheet is incomplete and lacking details, it is impossible to determine its effects on salmon.


Cal Fire Information Chief Scott McLean emphasized in a phone call with Wine Industry Insight that fire retardant drops are carefully planned to avoid streams and other bodies of water.

Manufacturer document sloppy, massively at odds with good science

However, that scientific study cited above did use Phos-Chek 259F in mart of its experiment and found it kills 50% of Chinook salmon even at a tiny concentration equal to 0.09% of the applied concentration.


However, the manufacturer-created MSDS document for the same formulation found Phos-Chek 259F  “Practically Nontoxic.” (see below). While it’s true that Coho and Chinook are different species of salmon, the extrapolation of effects between the two may vary.

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The massive difference between ICL’s MSDS “Practically Nontoxic” assessment and the published, peer-reviewed scientific paper raises doubts about the validity of the true toxic effects on humans. If the salmon numbers are vastly under-rated, are the human risks also?


In addition, assessing toxicity by using only old-school macro-measurements of determining immediate death offers no risk information about lethal diseases such as cancer which take years to develop or chronic illness caused by endocrine disruption. (See: Old Ideas, Old Science Cripple Federal Regulation for a more detailed discussion of this issue.)


Firefighters, citizens at greater-than-promoted risk?


Significantly, the ICL Performance Products MSDS was sloppy and didn’t test the actual formulation.


It’s not like ICL is a tiny company without the resources to conduct good science. It’s a multinational giant with global operations and more than $5 billion in annual revenues.


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