Certified Industrial Hygienist’s Guide for Recovery for Indoor Environmental Issues.
by Dave Gold, CIH CSP
President, Gold Health and Safety Consulting, Inc.
January 29, 2025
Being born in, and having lived in the greater L.A. area all my life, like most long-term residents, I’m very familiar with the havoc wildfires can wreak. I remember the September 1970 fire, which burned all the way from where the 405 Freeway exits the San Fernando Valley at its north end, towards the west behind Chatsworth, and then south all the way down to the beach. This one burned down homes within my subdivision; we knew families that lost their homes. I was 11 at the time. During the fire, my two brothers and I were out stomping ashes and watering our shake roof, much to the dismay of my Grandparents, who were yelling at us to get off the roof and stop our nonsense (Grandma and Grandpa were watching us while our parents were on vacation out of the country). This fire really started the debate about the safety of wood shake roofs.
This time, the fires have hit even closer to home, as direct family members lost their home in the Palisades. They are doing ok and are making arrangements for moving on. I had lived in the destroyed house for a summer in the 1980s, and had visited the home many, many times. I knew the Palisades community pretty well.
As a health and safety professional, for many years now I have helped clients recover from home and business fires. I’ve also helped with from what is termed “Secondary Wildfire Smoke Damage.” This means the property did not actually burn down, but was nearby the fire and was affected by the smoke and debris plume. A quick search of company records showed we have been working in this area since at least 2010. More recently, we did both indoor and outdoor environmental sampling work following the fires in 2023 in Lahaina, and the 2018 Woolsey Fire in Malibu. So, dealing with wildfires that affect urban areas is not at all new to me.
Looking Back
Up until the late 2010’s, the focus on the recovery from secondary wildfire damage in the indoor environment has been on removing combustion particulates (primarily ash, soot, and char) and smoke odor. The current American Industrial Hygiene Association’s (“AIHA”) “Technical Guide for Wildfire Impact Assessments for the Occupational and Environmental Health and Safety Professional,” which was issued in April 2018, mainly discusses these concerns and seems to steer away from much beyond cleaning up combustion particulates. On a side note, I understand that a new guide should be released by the AIHA soon. It will be interesting to see the updates, which might prove to be very helpful.
With the recent fires, there have been public health officials stating the fires could have caused a veritable stew of toxic materials posing a significant health threat. This concern has been loudly echoed by the media and on social media, to the point of near hysteria, considerably scaring some folks. Some people are saying that it will be years before it will be safe to live in the affected neighborhoods. The public has reacted with a high degree of concern. As a result, we have been deluged with calls about the situation. The level of concern about toxins from the fire is a relatively new thing, certainly with both the number of people affected and/or concerned, and how seriously it is being taken. However, this is not the first time a vast number of homes have burned down. For instance, in the 2017 Tubbs Fire in Santa Rosa, over 4600 homes burned down. So, what exactly is the real concern for indoor environments? Let’s discuss.
Indoor Health Issues and What We Know
In doing research on wildfires and health issues, there are several studies that link airborne particulate matter (especially in the 2.5 micrometer range, which is termed “PM2.5”) and chronic health problems. These mostly involve the respiratory system, but there have been some links made with an increased risk of heart disease and dementia. There have also been some concern about carcinogenic chemicals being present. So, protecting yourself from airborne settled ash and other combustion particulates is important.
There is a lot of public concern about toxic contamination from the fire smoke and debris, including the presence of asbestos, lead and arsenic, lithium from electric car batteries, and other toxic chemicals. While there seems to be a decent amount of research about the dangers of particulate matter, there are scant studies about toxic concerns from urban wildfires. A series of studies from homes not destroyed by the 2021 Marshall Fire in Boulder, Colorado found elevated levels of volatile organic compounds (“VOCs”) and Polycyclic Aromatic Hydrocarbons (“PAHs”) indoors where other homes burned nearby. The studies also found that occupants were suffering from a variety of health complaints, including respiratory problems and headaches. While this study anecdotally found that cleaning the homes reduced complaints, they did not correlate home cleaning with actual lab results.
Where Does That Leave Us Now?
As of this writing, we don’t have a lot of data back from the testing we’ve performed in fire-effected homes and businesses. Thus far, and from our own limited data set and some through-the-grapevine information we’ve heard from other consultants, we are not seeing asbestos contamination, and lead contamination is at acceptably low levels. We found arsenic in one soil sample higher than what is supposed to be present, but we also know from the Woolsey Fire that local natural soil arsenic levels can be even higher, and therefore, the one outlier result should not be considered problematic. We are hoping to see more data in the coming weeks and will update this blog as warranted.
Should I Do Testing In My Home or Business?
I’m frequently asked this question. Let’s start with basic testing, for combustion particulates, aka ash, soot, and char. My opinion and experience is that the necessity of testing for combustion particulates has more to do with insurance claims than anything else. If combustion particulates are clearly present (most likely on windowsills), you know you were affected. The issue here is how cooperative your insurance company is being about covering clean-up (and environmental testing too – many insurers will not cover the costs). If it appears that the insurance company is going to cover cleaning costs, I’m not convinced that these samples are worth the expense. However, if the insurance company appears to be balking, or if you may be involved with a legal issue involving the impact to your home, getting samples is critical. My expert witness experience tells me that this could prove to be extremely important in a potential lawsuit, as are your, and our, photos of the damage.
Should an extensive chemical analysis be performed on the ash? It is expensive to get this done. Also, at the end of the day, it probably won’t change the need to clean up, or the method that will be used. So, in my opinion, I would skip this.
At least at this point in time, it makes sense to get a few samples from effected areas for asbestos, lead, and probably arsenic as well. The concern here is that these chemicals could have come in from older homes that have been destroyed; most likely it will be contained within the particulate matter, so where you see accumulations of particulate matter is where contamination should be at its worst. As mentioned above, the limited data we have at this time seems to indicate that this is not a problem, but that could change as we get more data from the field, and from different areas/proximity to burned areas.
As far as air samples are concerned, we offer a variety of tests. It may make sense to test for airborne asbestos fibers. It is not terribly costly. On the other hand, if you are not seeing asbestos on surfaces (from the wipe samples), I would suspect it will not be present in the air. So, I don’t think asbestos air samples are of the utmost importance.
Samples for both VOCs and PAHs may make sense. As mentioned earlier, we have seen some research blaming these compounds for ongoing building occupant health effects. However, these samples are quite expensive, especially if the lab turnaround time is rushed. Trying to perform a VOC study with a meter is almost completely worthless; the best way to do this is by following EPA Method TO-15. To keep the cost down we are running these samples with one week lab turnaround time, but we do have some people asking for rushed results. Lastly, although it is interesting to see what the initial picture looks like, it may be more cost effective to wait until after the cleaning is done, as it will most likely not affect either the need to clean nor how it is performed.
At this point, and after our research (talking to labs, talking to other consultants, reviewing articles) the above list of sampling types seems to be the “go-to” for testing. If we learn of additional recommended testing information that makes sense to do, we will amend this article and include it.
How Do I Know if My Home/Business is Safe?
This is a difficult question to answer. There are specific legal standards for what is acceptable indoors for asbestos and lead. Aside from that, there are no hard standards. So, it is hard to say what is “safe” or “unsafe” with any sort of objectivity or backing.
Beyond the few legal standards, we are either comparing lab results to a standard we’re adapting from elsewhere (such as using the EPA ambient air quality standards for indoor particulate levels), consensus organization guidelines, or looking at risk factors provided by agencies such as the EPA and California’s Office of Environmental Health Hazard Assessment (“OEHHA”).
The topic of risk with chemical exposure needs explanation. The duration of exposure, the concentration of the material, and the route of entry into the body should all be considered. This will lead to understanding a human’s dose. Let’s also remember the most basic law of toxicology, “the dose makes the poison.” Small doses mean little, and the bigger the dose, the bigger the problem.
Risk standards also need some deeper understanding. The EPA Recommended Screening Levels (“RSLs”) are set for risk of 1 in 100,000 for non-cancer health problems or 1 in a million for cancer risks, with exposure for 30 years. This means, for instance, if you had a listed carcinogen in your home at the RSL, and lived there for 30 years, you would have a one in one million chance of getting cancer from it. Considering that the cancer risk in the USA as a whole from all possible causes (including genetics, cosmic radiation, x-rays, lifestyle, pollution, etc.) is one in five, I don’t think this is significant. However, we cannot decide for clients what their acceptable level of risk is.
Another issue is how good the studies are to date, and how good is the lab methodology and sample collection methodology. For example, VOCs can easily change over time, so what you see today may be a lot less of a problem in a few weeks.
How Many Samples Should be Collected?
Personally, I don’t think you need to collect a great deal of samples, maybe 3 to 5, depending on the type of sample, the size of your home, and your budget. You’re just trying to prove the point that the home was affected. The contaminants themselves are not going to be vastly different in different areas of the home. If the home is affected, most likely the entire home is going to get cleaned by default. Plus, we certainly can add to the report a list of the areas where damage was observed, even if it was not directly sampled.
How Are Homes Typically Cleaned? Is That Good Enough?
This generally consists of HEPA vacuuming all areas and damp wiping while running large HEPA filters. Areas wiped down may include affected horizontal areas, but may extend to nearby walls and ceilings, furniture, small items, etc. Items that were stored in cabinets or in rooms that didn’t appear to be impacted by ash/soot/char may not get cleaned. In essence, anything visibly dirty gets cleaned. Some items, such as special artwork, electronics, etc. may be removed off site for cleaning by special vendors.
If smoke odor is present, this is usually dealt with by running ozone machines for 48 hours. People are not allowed to be present when this occurs. Some items, such as couches and other furniture, may be taken off site to be ozonated.
As far the “is it clean enough?” question goes, as mentioned above, the study from the Marshall fire found that in homes where remediation had been performed, occupants had less health complaints.
What About Porous Items, Like Pillows, Carpeting, Mattresses and Couches?
These items are difficult to test for several reasons. First, most testing is going to destroy the item. You wouldn’t very well want to keep a couch with a big hole in it where we took the sample, would you? On top of that, the analysis of these samples is going to be expensive and probably not very scientific quantitatively. Lastly, as I mentioned above, there is the whole discussion again about “how safe is safe.” There are very little standards on how much chemicals can be in these items in the first place.
As far as cleaning goes, these items can be HEPA vacuumed off and possibly cleaned with steam or extraction cleaners. Smaller items like pillows and nylon backpacks can be washed or dry-cleaned. Ozone treatment is also an option for removing smoke odors.
What About My Clothing and Bedding?
Items that you can either wash in regular laundry or dry clean, should be cleaned before putting back into use. The cleaning should remove particulate matter and the heat from drying them will remove organics. Dry cleaning should remove PAHs. If you get the smoke odor out, that is a pretty good sign the items are okay. If you cannot get the smell out, they may need to be deodorized using ozone or disposed of. Note that it is also difficult to test these items for several reasons.
If these items can’t be effectively deodorized, they should just be replaced. Many people will just want to err on the side of safety and just get rid of them, whereas people that have only light levels of damage and little smoke odor can probably safely clean and keep them.
What about the HVAC System?
If the house has been impacted with smoke odor, the systems should be professionally cleaned. We recommend that persons specifically experienced with duct and system cleaning do this work, which may not be your HVAC technician.
Do We Need to Remove Drywall?
In wildfire situations – even such as those where multiple homes burn – this step is not usually needed nor is it traditionally performed. This is more likely to be required when there is a fire within the building itself, as the heat of the fire can drive smoke though any possible entry point into wall and ceiling cavities. This pressurization does not generally occur in wildfires, but there may be some extreme cases where drywall removal may be necessary. Probably the best way to figure this out is to open some wall cavities, remove some of the suspect insulation to an off-site area – away from the burn zones – and check it for smoke odor. If it does, the insulation should be removed.
Can I Clean up the Ash etc. Myself?
Unless it is a small area (like just a few windowsills) and no smoke odor, we recommend that the interior be cleaned professionally. If you are going to do cleaning yourself, you should make sure to use HEPA vacuums and damp wipe all affected surfaces. Any kind of household cleaner – 409, Fantastic, Simple Green, Fabuloso – will get the bulk of the contamination out. Also, you will want to protect yourself from airborne exposure to the dust using at least an N95 respirator (P100 would be better), gloves, and safety glasses. You may also want to wear a disposable Tyvek suit (or similar). Most of these items can be found at Home Depot or other major hardware stores. Home Depot also rents commercial cleaning equipment, including HEPA vacuum cleaners and air filtration. Also make sure to use good personal hygiene and clean your hands before eating, smoking, or using the bathroom.
Is Cleaning Good Enough?
Another great question. Studies have shown that a good cleaning can lessen the contamination overall, especially with air quality and affected surfaces. There is some question whether those methods are enough for VOCs and PAHs. VOCs can be removed by heat, but it may be more difficult to get rid of PAHs. There is not a lot of data about this.
Should I Test/Reinspect After Cleaning?
At this time, I would say it is a good idea, but it is not clear exactly what tests should be done, and if they are worthwhile.
First of all, any post-remediation inspection should include a visual check of areas, including the attic. As far as surface samples go, these are not very expensive. If we don’t see much material remaining on the surface, the samples are highly likely to be negative and may be a waste. Surface samples for asbestos and lead are probably not warranted if none was found during initial testing, or if we find the trend towards this contamination overall in the burn zones and nearby is not a concern. As stated earlier, we only have a little data on this at this time.
There may be value in testing any combustion particulate debris observed during a post-remediation inspection, indicating that the clean-up was dissatisfactory. The remediation contractor and/or insurance company can then be presented the sampling data if they push back on any correcting deficiencies.
As mentioned above, it is going to be technically difficult and not very practical to test your items for chemical contamination, like clothing and furniture. Also, this can be quite expensive. At this time, I can’t recommend it. Furthermore, your main concern should be the indoor air quality. If the indoor air quality looks good, it indicates that the interior is probably reasonably clean and safe.
As far as air samples go, respirable particulate levels is a great place to start. In comparison to other sample types, they are more reasonably priced. It’s a good indication of the overall indoor air quality, and as mentioned above, particulate matter is likely to the major health concern if it remains at elevated levels. So, my feeling is that these samples are worthwhile.
Asbestos air samples post-remediation may also make sense, depending on what we find during initial assessments. They are also reasonable in cost. If we don’t find asbestos indoors initially, or don’t see it showing up in results from the overall affected areas, it’s probably not warranted.
Samples for Volatile Organic Compounds (“VOCs”) and Polycyclic Aromatic Hydrocarbons (“PAHs”) may be worthwhile, based on the study results I discussed above. However, these samples are quite expensive, especially if you request the lab results back quickly (lab turnaround time is also part of sample fees). Also, the capacity of the laboratories may be impacted as the recovery efforts gets ramped up. This might mean that it will take longer than it’s supposed to, to get the lab results. We’re already seeing a little of this at this time. As mentioned above, some clients are already paying for more extensive sampling studies that includes air samples, so we should get a better sense of how important these tests are in the coming weeks.
In regards to the number of post-remediation samples, as discussed above, that is going to depend on budget and the size of the home. While us science nerds typically like lots of data, it’s not coming out of our pocket, and you may not have insurance coverage for post-remediation testing costs. My preference is in proving the general idea that the overall indoor environment is reasonably clean, with a focus on sampling the areas with the most damage and/or “bracketing” the floorplan, rather than sampling each and every room.
What About Ongoing Pollution From the Neighborhood?
It’s understandable that people would be concerned about this. However, the remaining debris are mostly going to consist of ash and possibly asbestos. Prior to demolition/clearing the debris, the site must be checked for asbestos and other toxics. Also, during the demolition, per SCAQMD rules, generating a lot of dust is not permissible. The contractor has to take precautions to make sure this does not happen, usually just by wetting the site. You always have the option to have us come and retest later.
What is Gold Safety’s Testing Services and Costs?
We can perform all of the tests mentioned above, and more. We also can provide a Scope of Work for remediation, which lists our recommendations for what clean-up should be done. Many clients ask for this. The Scope of Work can be provided to a remediation contractor or your insurance company, which can be quite helpful in many respects. As far as the cost goes, that is going to vary with the services, samples, and lab turnaround time, clients choose.
We have already seen some instances of contractors and consultants taking advantage of clients, either through inflated pricing, and/or unnecessary amounts of samples. We will never do this. People that take advantage of others suffering from a disaster are despicable! We will be transparent and fair with our pricing. To that end, we have prepared a price list for our testing services related to the fires. You can get this emailed to you from our office.
In Closing…
Today starts the Chinese Year of the Snake. Babies born in the Year of the Snake are said to be resilient, courageous, and have positive outlooks. Let’s hope that all those suffering from the L.A. Wildfires can muster up those attributes and build better, safer neighborhoods.