AP on Fire Retardant

Here’s the link.

Below is an excerpt.

Fire retardant doesn’t attempt to put out wildfires or even necessarily halt flames in their advance. Consisting primarily of ammonium phosphate — fertilizer, basically — fire retardant is formulated to slow down the combustion of trees, brush and grass.

The idea is to give firefighters time to mount a ground attack. The ground forces clear away flammable material in a wide line around the edges of the fire. They hem in the flames and eventually a soaking rain falls or the fire just burns itself out.

Often, even a fully contained high Rockies wildfire will smolder, sputter and flare for weeks or months, into autumn and the first significant snows.

The U.S. Forest Service spent $19 million on 23 million gallons of retardant last year, which was unusually busy for wildfires.

“We’ve observed streams for miles be sterilized of all their fish life. Tens of thousands of fish can be killed in one dump,” Stahl said.

Meanwhile, very few fish poisonings have been documented. Even Montana U.S. District Judge Donald Molloy, in siding with Forest Service Employees for Environmental Ethics in its second lawsuit over fire retardant, pointed out in his 2010 ruling that only 14 of 128,000 retardant drops over eight years killed protected fish or plants.

Ammonia in watersheds from fire retardant is not a human health risk.

Many endangered Rocky Mountain plants are adapted to thrive in very limited habitats with poor soils. Fire retardant can encourage the growth of invasive weeds that can crowd out native plants that otherwise would have a competitive advantage, said Glen Stein, a Forest Service fire ecologist who led the effort to write the new rules for fire retardant.

Stahl said the Forest Service hasn’t proven with field studies that fire retardant helps.

“We throw it on for the air show,” Stahl said.

There’s a reason why fire retardant isn’t tested in the field, said Stein.

“The problem that I have with what Andy wants us to do, is out there in the wild, you have so many variables that are constantly changing. You’ve got slope, you’ve got aspect, you’ve got wind, you’ve got temperatures. It’s hard to know what the result of the retardant is versus some of the other variables,” he said.

Anyway, he’s seen fire retardant work in the field, such as when a DC10 tanker plane dumped thousands of gallons at a California fire a few years ago.

“Five miles long, I drove that whole road where we dropped it. There were two little spots where it went into the retardant and stopped. And the rest of it just stopped at the retardant. So I know it’s effective,” Stein said.

4 thoughts on “AP on Fire Retardant”

  1. Glen’s comment in the article — “You have so many variables that are constantly changing. You’ve got slope, you’ve got aspect, you’ve got wind, you’ve got temperatures. It’s hard to know what the result of the retardant is versus some of the other variables” — is precisely why a statistically valid study is needed to test real-world retardant effectiveness.

    In an earlier blog post, Aerial Fire Retardant is Like Avastin, I pointed out the difference between policy-making based upon anecdotal stories versus policy-making based upon properly controlled studies.

    Women and their breast cancers have “so many variables that are constantly changing.” They have different genetics (like the slope, wind, aspect, temperature differences of fires), different life histories and environmental conditions. That’s why the FDA requires randomized, controlled trials before it approves a drug therapy. Notwithstanding Avastin’s anecdotal success stories, the controlled studies showed no evidence that Avastin extends life or improves quality of life. Avastin also has adverse effects including severe high blood pressure and hemorrhaging, just like fire retardant, which kills fish and pilots.

    Are homes, sage brush and forests more important to save than women’s lives? Are we more willing to waste money using unproven and expensive firefighting tactics than we are willing to waste money on unproven and expensive cancer treatments?

    A statistically valid retardant effectiveness study is easy to design. With over 90% of wildland fire ignitions receiving no retardant use, the universe of controls is large. All that is needed is proper study design (random allocation of retardant use to a portion of ignitions).

    In the absence of a proper study, one can’t help but wonder that the Forest Service doesn’t want to know the answer.

    • So, Andy, as a veteran of several experimental design classes, I don’t see that medical controlled trials and fires are the same at all. For example, we used to do progeny tests to test genetic differences among trees. We tried to keep the sites as uniform as possible so that differences among treatments would be expressed. I am with Glen on “forest fires interaction with suppression tactics and ongoing changing conditions” is nothing like an agricultural field trial or a medical trial.

      I would argue that a statistically valid retardant effectiveness study is NOT easy to design. These folks, who are the scientific experts, did not seem to find it too easy to look at fuels treatment.. check out this webinar. You have to have good data, you have to run models and you have to make assumptions, and the use of retardant would change other aspects of the suppression strategies.

      It seems like you have chosen a certain approach and declared that to be the “correct” way of answering effectiveness. Observation by practitioners doesn’t count. Photos don’t count.

      Also, I’m not sure that retardant per se “kills pilots”; seems like water would have not have the environmental effect that you have raised but dumped from the air might equally endanger pilots. Or are we talking safety of helicopters vs. airplanes?

      Here’s another link from earlier to my cousin on the prairie in Texas who also observed retardant “working” and was grateful.

  2. Interesting comment from Firehouse.com-

    aside that the National Interagency Fire Center’s own documentation states that
    retardant doesn’t put out a fire, it is interesting to see how the USFS got
    where it is with respect to just one company providing retardant, particularly
    since the USFS seems to imply that now that sodium ferrocyanide is no longer
    used the toxicity concern is gone. This
    is not about the chemicals, it’s about the USFS.

    The key statements in the story come from Cecilia
    Johnson, fire chemicals technical specialist at the agency’s Missoula
    Technology and Development Center in Montana.

    Andy Stahl, executive director of Forest Service Employees for
    Environmental Ethics states at one point in the story “The case for
    retardant use is not sufficiently strong to offset the environmental

    Rubbish, say Forest Service officials, who cite decades of rigorous
    laboratory testing and relate the accounts of plenty of ground and aerial
    firefighters who insist that fire retardant not only works, it works well. “All of the retardants as concentrates
    are practically nontoxic. They’re even less toxic by the time they’re
    diluted,” Johnson said.

    longest of the “rigorous laboratory testing” is the corrosion test which takes 90
    days. The other tests range from 14 to
    21 days. None are done concurrently, so
    it takes just 2 years for the USFS lab to test a chemical.

    Before we get to the history of the USFS and ICL, lets
    take a look at a fish kill in California.
    Its important because in this instance, the scientist brought in by
    California EPA calls into question how the USFS lab can label retardant as “practically
    nontoxic” .

    California has had a number of fish kills. The California Environmental Protection
    Agency (Cal/EPA) lists one such incident on its web site:


    memo on this fish kill can be summarized as follows:

    D. Cooper (Professor, Department of Ecology, Evolution, and Marine Biology,
    University of California, Santa Barbara, CA 93106) was brought in to determine
    what killed fish in Maria Ygnacio Creek following the Jesusita Fire in Santa
    Barbara County, CA in mid-May 2009.

    It was reported that there were Phos-Chek
    deposits in and near the stream upstream from the waterfall.

    The fish kill was noted immediately after
    Phos Chek was dropped on a hot spot in the upper Maria Ygnacio basin and
    occurred downstream of sites where Phos Chek was observed in the stream, so it
    seems likely that Phos Chek elevated ammonia levels resulting in the fish kill.

    The Material Safety Data Sheet provided by
    the USFS for Phos-Chek 259F (115 and 160 mg/L Phos Check) are within the range
    of values reported in the literature; however, the 96-h LC50 values for rainbow
    trout reported on the Material Safety Data Sheet for Phos-Chek D-75F (> 1000
    mg/L) are clearly in error, being approximately an order of magnitude higher
    than Phos-Check 96-h LC50 values reported in the literature.

    The results reported in the literature
    reviewed carry considerable uncertainty and are likely to be conservative
    because they are based on laboratory bioassays. As has been noted by several
    researchers, it is not clear to what degree laboratory bioassays replicate and
    have relevance to field conditions.

    The Material Safety Data Sheets for these
    Phos-Chek formulations also are misleading because they list both forms of
    Phos-Chek as being “practically nontoxic” based on reported 96-hr LC50 values.
    Given the vast hatchery, aquaculture, aquarium, and fisheries literature on the
    toxic effects of ammonia on fish and on ways to mitigate ammonia impacts, it is
    very puzzling that Phos-Chek is listed as being practically nontoxic to aquatic
    life. Conclusions of the toxicity of a material depend on both concentrations
    of the major toxic component (e.g., ammonia) occurring in affected water
    bodies, as well as on the concentration of this component which kills aquatic

    Because fire retardants are applied as
    highly concentrated solutions, Gaikowski et al. (1996) concluded that “the
    possibility of concentrations close to the 96-h LC50 in the environment are
    real and render the terms “practically” and “relatively harmless” in this scenario
    to be irrelevant”.

    Fish kills during or immediately following
    fire-fighting activities have been reported throughout the western U.S. and
    Alaska, and have usually been attributed to aerial application of
    ammonium-based retardants resulting in direct drops of retardant into streams
    (Norris and Webb 1989, Minshall et al. 1989, Minshall and Brock 1991, Buhl and
    Hamilton 2000, Dunham et al. 2003).

    should be noted that in the United States in 2010, there were 11,070,722 mixed
    gallons of chemicals dropped from air tankers.
    Of this, 11,062,617 mixed gallons of retardant (99.93% of all the
    chemicals dropped) came from one company (ICL Specialty Chemicals – the parent
    company is Israel Chemical Ltd.)

    ICL employs
    3 ex-senior USFS personnel who’s combined career
    with the USFS exceeds 100 years. In 2004, ICL
    received a patent for a retardant formula and two months later the USFS changed
    their specification. The new
    specification happened to match the patented retardant.

    company that had 75% of the US retardant business (Fire-Trol) now had none of
    the business, because of the patent.
    ICL, which had 25% of the US business, now has 100%, at least until the
    patent expires. Fire-Trol did sue the US
    Government over the fact that the “bid process” was essentially a sole source
    contract because ICL would not license the patented retardant. Israel Chemicals solved the problem by buying

    ICL Specialty Chemicals, formerly Astaris, is the only supplier of retardant
    to the US Forest Service. Because of an
    Interagency Agreement(doesn’t include the BIA) requiring the use of US Forest
    Service approved chemicals, by default, in addition to being the largest
    supplier to the USFS, ICL is the largest supplier of chemicals to the US Dept.
    of the Interior. California mandates the
    use of US Forest Service approved chemicals and ICL has a “mandatory
    use” contract with the State of California – all fire fighting retardant
    used by State agencies must be ICL chemicals.

    The US Forest Service tests are primarily designed to establish values for
    toxicity, biodegradability and corrosion.
    These tests are performed for “informational” purposes. These tests are done to ensure that the
    chemicals used are safe for firefighters, citizens and the environment.

    The bulk of the ICL patent filing is essentially stating the science behind
    the invention. One section of the patent
    filing is titled “BACKGROUND OF THE INVENTION”. This section provides additional support to
    what we have said for many years, that being on the US Forest Service chemical
    list does not necessarily mean a chemical is safe for firefighter, citizens or
    the environment. Bear in mind, the patent
    application was filed by the company that is now the largest supplier to the US
    Forest Service – before the patent, ICL only had about a 25% share of the
    retardant market. Another USFS approved
    chemical,Fire-Trol, had a 75% share of the retardant market.

    Without using the name Fire-Trol, the ” BACKGROUND OF THE
    INVENTION” is primarily a discussion about the toxicity and corrosivity of
    Fire-Trol. Fire-Trol passed all of the
    US Forest Service’s “rigorous laboratory testing” requirements, so, if the US
    Forest Service holds the position that the only way for a chemical to be safe
    for firefighters, citizens and the environment is to pass its testing, then
    presumably there could not have been a problem with either the toxicity or
    corrosivity of Fire-Trol.

    I have provided several excerpts from the ” BACKGROUND OF THE
    INVENTION” section of the patent filing.

    “Aerial application of fire-retardant compositions to combat the
    spread of wildland fires is common. The composition of fire retardant
    concentrates designed for managing and controlling wildland fires are of two
    general types: those that when mixed or diluted with water to end-use
    concentration, result in a gum-thickened solution, and those that do not
    contain a gum thickener and, consequently, result in
    water-like solutions, which are not rheologically modified and exhibit inferior
    drop characteristics.”

    “Fertilizer grade ammonium
    polyphosphate liquids have been used as aerially applied fire-retardants. These
    liquids have certain advantages in comparison to other fire-suppressing compositions
    since they can be transported and stored prior to use in the liquid form rather
    than being mixed from dry ingredients. However, concentrated liquid fire
    retardants and solutions prepared therefrom are extremely corrosive to aluminum
    and brass and mildly corrosive to other materials of construction used in
    handling, storage and application equipment.”

    “Since wildland fire retardants are most frequently transported to the
    fire and applied aerially, it is imperative that corrosive damage to the
    materials of construction of fixed-wing aircraft and helicopters be minimized.”

    “Accordingly, the United States Department of Agriculture (“USDA”) Forest Service has established,
    in”Specification 5100-304b (January 2000)
    Superseding Specification 5100-00304a (February 1986),”entitled”Specification
    for Long Term Retardant, Wildland Fire, Aircraft or Ground Application”
    (hereinafter, “Forest Service Specifications”), hereby incorporated
    by reference in its entirety, maximum allowable corrosion rates for 2024T3 aluminum,
    4130 steel, yellow brass and Az-31-B magnesium, and
    weight loss procedures for determining such corrosion rates. For example, the
    corrosivity of forest fire retardants, in concentrate, to aluminum, steel and
    yellow brass must not exceed 5.0 milli-inches (“mils”) per year as
    determined by the”Uniform Corrosion”test set forth in Section 4.3.
    5.1 of the aforementioned USDA, Forest Service Specifications. If the product
    is applied from fixed-tank equipped helicopters, the corrosivity of the fire
    retardants to magnesium must not exceed 5.0 mils per year.”

    “In an effort to address the corrosivity problems encountered with the
    use of fertilizer grade ammonium polyphosphates, sodium ferrocyanide (my
    note: this is Fire-Trol) was
    incorporated into the corrosive compositions. Sodium ferrocyanide has proved to
    be an effective corrosion inhibitor in fire retardant compositions containing
    ammonium polyphosphate fertilizer solutions. While sodium ferrocyanide is
    effective as a corrosion inhibitor, several disadvantages of its use make its
    incorporation into wildland fire retardant compositions undesirable.
    Specifically, the environmental and toxicological safety of ferrocyanides is, at best, questionable. When exposed to acidic
    conditions and/or ultraviolet radiation from natural sunlight, the ferrocyanide
    radical readily degrades releasing free iron and cyanide and/or hydrogen
    cyanide, which are toxic to humans, animals and aquatic life. Further, free
    iron emanating either from decomposition of a portion of the ferrocyanide radical, or introduced from other components or
    impurities within the composition, will subsequently react with remaining non-
    decomposed ferrocyanide to form ferrous ferricyanide
    (“Turnbull’s Blue”) or ferric ferrocyanide (“Prussian
    Blue”), which emit a persistent blue-black or indigo- blue coloration,
    staining all that they contact. Consequently, neither ferricyanide nor
    ferrocyanide can be used in fire-retardants that are expected to fade and to
    become non-visible over time, for example, in fugitive retardant compositions.”

    “The magnitude of the above concerns is increased since wildland fire
    retardants are generally applied aerially in a less than completely controlled
    manner. Due to the presence of variables such as vegetative cover, smoke, or
    wind drift that affect the trajectory of the free-falling solution, aerially
    applied wildland fire retardant solutions may land on or near people, animals
    and in bodies of water, or on soil where it could enter the water supply. ”

    “Accordingly, there is a need to provide safe and acceptable wildland
    fire retardants for the suppression or management of wildland fires that are
    not corrosive to the equipment associated with the transportation, handling and
    application of the retardant, have favorable rheological and aerial application
    characteristics and are environmentally and toxicologically friendly, thereby
    avoiding the above disadvantages. ”

    Essentially, Fire-Trol went through all the USFS testing and was found to
    meet the specification for a chemical that is safe for firefighters, citizens
    and the environment. A company with a
    long record of working with the USFS came up with a patent for a
    “safe” gum thickened retardant and the USFS changed the spec to be
    able to use the “safe” retardant.
    Coincidentally, be changing the specification, the USFS’s action has
    resulted in ICL having a sole source contract until its patent expires.

    And, as you have already read above this “rigorously laboratory tested”
    safe gum thickened retardant kills fish with the same ease the “old” rigorously
    laboratory tested chemical did when accidently dropped in water.

  3. Blaze, I don’t understand your points clearly.

    First, no one said fire retardant stops a fire, it slows it down so that other tactics can get used. Fire information officers and incident commanders have said that very clearly.

    Second, you seem to be implying that if a chemical could have a negative environmental effect, it shouldn’t be used. However, fertilizers can have negative environmental effects. Fire camps have negative environmental effects, as do all the gasoline powered vehicles used. And fires also kill fish, and the resulting sedimentation can destroy their habitat at least for years. Actually, fish people kill fish with poison intentionally in some cases to encourage native species.

    I am not an expert on fire retardant, but it seems like it is useful, and people are trying to make it more environmentally friendly.

    So who gets to decide if it’s environmentally friendly “enough” to use? The courts? The evacuees of some fire? The fire community?


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