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Housefire Toxicity Report

Oct 13, 2023

I have read enough, talked to enough people, and found/linked a few guiding references to be extremely worried about residual environmental toxins left by the Lahaina Fires. I will limit my concerns to inhaled toxins for now:  

Firefighters realize that the toxins left behind by forest fires (wood and brush) are very different than from house fires. The Lahaina fires toxicity will be based on house/car fires.   The residue (ashes) from the unusually hot Lahaina fire (8 Aug 2023) is extremely toxic.  While we are more familiar with dangerous chemicals from fires of old structures (say, lead and asbestos), the newer structure with synthetic materials (carpeting, vinyl, PVC, acrylics, rubber,  etc) pose new threats with their associated toxins, with new concerns on almost a decade by decade basis.  Burning synthetics can emit an array of  heavy metals which we can address on an elemental basis but there are potent dangerous carcinogens, like the class of Dioxins, specific to the quantity, type and how the synthetic materials were “burned”.  

While much has blown away in the winds over the past months, there are pockets of ashes/dust that remain, to be uncovered when the burned sites are disturbed.  One alarming finding was that in 2018 the number of cancer deaths from the World Trade Center catastrophe exceeded the number who died on the day of 9/11.  These were excess cancer deaths (and still rising) of those exposed to toxins on that day and during the long erm clean-up. In general exposures are to survivors of the initial trauma, first responders, those in nearby communities and families of first responders (who did not fully decontaminate). 

The clean-up of the Lahaina Fire site may take years to reduce the risk of toxins (environmental half life of Dioxin 7-15 years, and this is the just the half-life). 

We recognize the growing emotional need for families to visit their home sites for various reasons.   This general effort has been called the Re-entry Program (RP).   I think the RP needs to emphasize two components simultaneously.  One is to clean-up to standards safe enough to reoccupy the land (for residential) forever.  The other is to allow short term interim visit (may be recurring) for emotional and practical needs.  The longer it takes for the first component to complete, the more important the second component becomes.   If the second component is not emphasized many will enter illegally and try to stay for as long as possible.  This is not only a health risk to themselves but to others (in the area, and on exit/poor de-con).  The public needs to know ASAP that the second component (short visit) is a real alternative and has the commitment of those in charge.  If not, then many illegal entries will be made or those who obey the laws will become despondent and depressed.  We are already being asked about health risks of toxins and PPE guidelines PPE for those who “plan someday” to renter.  Last night I was asked to review the extensive advice in Spanish.  

After consulting with Dr Eric Sergienko who supervised RP for the Oak Fire of Mariposa County Ca and Dr David Schoenfeld (ASPER, board member)  the following plan is proposed:  

PIO’s announce a general plan for the program.  The reasons, benefits,  risks, and rules.  We invite public input, though we might have to start pilot projects quickly since the need is so pressing.  

Mapping street by street, safe access for the street is confirmed. EPA/FEMA has already completed the first walk through phase removing high risk threats.  A list of residents (or their vetted representatives) are identified for the target street (s) and case RP case managers are assigned.  The safety education is covered (both trauma and toxins)  and the rules are set forth.  One or two people per home?  Perhaps 45 minutes on site, minimize dust, who is allowed to retrieve and rummage, small one gallon water containers for dust control, do not take ash – only momentos, how much momento’s (one gallon zip lock), fotos but only own home and only residents, no pets, N95 mask, gloves, etc, etc….

Transportation will be provided – but carpooling will be used.   Handwashing systems before re-entry to vehicles.  De-con footwear?   Carwash vehicles each day.   For each block of street there will be a supervisor to deal with all issues, a medic and security for every 5 blocks.  

We start small as a pilot study and hope to do gear up to 200 a day?  This amount would allow for a revisit of 2000 homes once every 10 days. 

We will have frequent PUBLIC reports to track the program and new suggestions. Community suggestions how to deal with bad behavior. The bottom line is that we want this to be a COMMUNITY sponsored effort to change the norm away from illegal entry and reduce despondency during the long wait for definitive clean-up. I also don’t want a rushed clean -up job because the frustrated residents have been shut out of short-term visits.   I could imagine canoe clubs/hula halau having on site presence.   I expect maybe more physical help than security.    

Thank goodness we are used to N95’s masks from COVID. And that the toxins are particulate size.

References for housefire toxicity Started Aug 20, 2023:

  1. This is the link for “soot  webs” in corner – nice foto
  • This is link that 9/11 exposure deaths (cumulative excess cancer deaths from 10K cancers)  exceed first day deaths at 2018.  Much higher now (2023).  Don’t leave this kind of legacy that deaths from cancers are higher than first day deaths.  And for Lahaina we had a higher rate of children exposed the first day than 9/11.
  • A general reference to search by title and authors.   Heating of plastics to high temps with limited O2.  

I cant set up an active link:  Cut and past the following:  

Persistent free radicals, heavy metals and PAHs generated in particulate soot emissions and residue ash from controlled combustion of common types of plastic

Author links open overlay panelAthanasios Valavanidis a, Nikiforos Iliopoulos a, George Gotsis b, Konstantinos Fiotakis

  •  DEFINITVE article of Dioxins after house fires (2018).  Nice fotos of soot webs too:  Some cross references. Type of resp protection depends on level of Dioxins in ash.  :

A quote from the above:  “To illustrate just how toxic TCDD is, the lethal dose of lead for humans is 450 mg/kg of body weight. [88] Using the EPA’s 1997 carcinogenicity benchmark dose of TCDD as 0.0000156 mg/kg of body weight, [89] TCDD would be approximately 28,846,154 times more toxic than lead. Methylmercury is another toxic heavy metal, which has an estimated lethal dose of about 20 mg/kg of body weight. TCDD is approximately 1,282,051 times more toxic than Methylmercury.”

Lorrin Pang, MD, MPH

Maui District Health Officer

New references after 4 Sept 2023:

  •  This is a pretty deterministic model (20210 looking at amounts and types of chemicals in ash after fires.  The compared fires in households fires to fires of wild areas.  They realize that there are many non-targeted (unknown) chemicals) chemicals and measured this as bulk residues (GC and LC) of ash extraction.  They tested the “meaning” of these excess chemicals in a battery of in-vitro tests of “immunity”, mutagenicity (teratogenic and carcinogenic), inflammation,  etc. etc.  While housefires had more unusual products compared to wild burn areas there were not any difference in in vitro assays (last paragraph of paper).   Were the assays appropriate/sensitive enough to extrapolate to in vivo and epidemiologic observations?   Did their in vitro assays take into consideration combination effects of sub fractions of the bulk chemicals (they do raise this point?

Here is a useful quote to measure Dioxins  “ Recombinant cell lines containing an AhR-responsive firefly luciferase reporter gene have been extensively utilized as a simple and sensitive bioassay for the detection and relative quantitation of dioxin-like chemicals, PAHs, and related AhR activators in diverse environmental extracts, including ash.17–2”

  • Looks like drinking water messed up from leaching of burned plastics and from drawback of ash into the system contaminating (and slowly leaching the VOCs):
  •  More water issues and links:
  •  Lab test of leached material over 1 week for heated Plastic pipes.  But this needs to show persistent leaching.  :
  1.  Some indication that the problem of leaching can persist for months to years.  Better to ID and replace the plastic pipes>

“Rinsing heat-damaged pipes won’t always remove the contamination. While helping Paradise, California, recover from the 2018 Camp Fire disaster, we and the U.S. Environmental Protection Agency estimated that some plastic pipes would have required more than 100 days of nonstop water rinsing to be safe for use. Instead, officials decided to replace the pipes.

Even if a home is undamaged, we recommend testing the water in private wells and service lines if fire was on the property. If contamination is found, we recommend finding and removing the heat-damaged plastic contamination sources. Some plastics can slowly leach chemicals like benzene over time, and this could go on for months to years, depending on the scale of contamination and water use. Boiling the water doesn’t help and can release benzene into the air.” 


  1.  This recent 2023 Study by NYU looks at all types of disaster events and cancers.  They look at all types of causes (poor health care access, exposures, etc) – see their first Venn diagram.  There are all kinds of events from hurricanes to floods, to nuclear accidents.  They excluded first responder target groups, looking at elderly in the general population.  BUT they are so thorough that they gave a statement for just wildfire exposures:  

“The latency between exposure and disease detection may also explain the unexpected lack of studies related to wildfire eligible for inclusion in this review. Recent research suggests that older adults may be particularly susceptible to the negative health consequences of wildfire smoke; exposure to PM2.5 is associated with increased hospitalization and mortality among adults 65 years or older.7,64,65 Recent analyses found that individuals exposed to a wildfire within 50 km in the past 10 years had a 4.9% (95% CI, 2.8 to 7.1) relatively higher incidence of lung cancer than unexposed populations and a 10% (95% CI, 2.6 to 17.9) relatively higher incidence of brain tumors.66 Although this indicates a relationship between wildfire exposure and cancer incidence, the authors did not differentiate incidence by age at exposure. The 10-year latency period, suggested in other studies as an appropriate minimum lag time for examining the relationship between cancer incidence and exposure to environmental carcinogens,30,66,67 means that many wildfire events have occurred too recently to determine their carcinogenic effects, highlighting the need for future longitudinal trials among wildfire-exposed populations.”  We need to check their cross ref #66.,higher%20incidence%20of%20brain%20tumors.
  1.  Not good to quote media but this is rather timely 28 March 2023.  I guess for dioxin reports from the EPA we “get in line”.

and this from Mar 2023:

“These are important questions that deserve to be answered. Today there are no clear answers. Why? Because no one has done any testing for dioxins anywhere in East Palestine. No one. And, it seems, that the EPA is uninterested in testing for dioxins, behaving as though dioxin is no big deal.”

  1.  From the National Academy of Science:  Here is the quote to the chapter 6 preamble.  The issue is the mixtures and toxins combo – then they admit it is an issue but will only look at them singly.  I think the mixture of chemicals (Mass Spec “Xmas tree’ spikes)  of a wildfire synthetic burn is far different from the narrower tree of products of dioxin formed in the making of agent orange.  Or what OSHA might see in factories that make specific products.  

\This PDF is available at

The Chemistry of Fires at the

Wildland-Urban Interface (2022)

“Smoke from WUI and wildland fires consists of complex mixtures of the aforementioned toxicants,

which have the potential to interact with each other to modify the toxicity of single compounds (Zeliger,

2003). However, analysis of mixture toxicity and health effects is complicated. Thus, assessing the toxicity of

individual constituents is most often used to predict the toxicity of the mixture. Table 6-1 summarizes some

examples of key pollutants recognized in fire events along with general health impacts and common routes

of exposure.

Research need: A need exists to pioritize WUI-related chemicals of concern, their exposure potentials, and

their human health risks, with consideration of vulnerable populations, so that mitigation strategies can be


And I will assume from Ref 6 that the bioassays of even the mixture do not show clear differences from synthetic fires vs controls (forest fires).  The issues of bioassays were address above.  

  1.  The McGill study in Lancet

Note they talk about the principle of mixture (combinations) of toxins with novel effects. Then they spanned fires for 20 years.   If there is a timeline effect for most recent with most toxins that might be “balanced” out by latency since the recent fires have not had time to manifest with late onset illnesses (cancers, etc).   But they did say that the higher risk of brain and lung tumors was with the most recent years.  Although they did not talk about the kinds of materials burned, many toxins listed in their intro are from synthetic burns.  It would have been nice to look at the number of structures burned to see if there is a dose (number structures burned)  to response (cancers). The Lahaina fires had high number of structures burned.   

Observational Study Lancet Planet Health

. 2022 May;6(5):e400-e409. doi: 10.1016/S2542-5196(22)00067-5.

Long-term exposure to wildfires and cancer incidence in Canada: a population-based observational cohort study

Jill Korsiak 1, Lauren Pinault 2, Tanya Christidis 2, Richard T Burnett 3, Michal Abrahamowicz 1, Scott Weichenthal 4

Affiliations expand

PMID: 35550079 DOI: 10.1016/S2542-5196(22)00067-5

Free article

Here is the quote:  When they say within 50 or 20 km the methods section says this is a radius.  I have studied dust dispersion for other issues and I think particulate size which we worry about are “blocked” by mountains ranges over 3000 ft elevation.  

“For example, cohort members exposed to a wildfire within 50 km of residential locations in the past 10 years had a 4·9% relatively higher incidence (adjusted hazard ratio [HR] 1·049, 95% CI 1·028-1·071) of lung cancer than unexposed populations, and a 10% relatively higher incidence (adjusted HR 1·100, 1·026-1·179) of brain tumours. Similar associations were observed for the 20 km buffer size.”