ERMI NaySayers

Article Summary: After writing Mold Testing, I decided I needed a simpler way to explain the reasoning behind taking two side-by-side Swiffer samples in order to determine if a building is moldy. This method circumvents variables that otherwise can lead to poor results. Don’t listen to Inspectors that claim ERMI is only for research purposes or can only be used in limited situations. This is nonsense and I’ll explain why.August 26, 2015

The NaySayers

Think Outside the Box

I’ve read a few opinions of mold inspectors indicating that ERMI testing isn’t valid. Arguments made range from hiding behind the Office of the Inspector General (OIG) statement that ERMI was only intended for research purposes to the more thoughtful but still ill-informed position that ERMI can only be used in homes to determine if there is a potential mold issue – that it should not be used to evaluate the success of a mold remediation project. The later group of inspectors fails to realize the full potential of ERMI testing while the former are either too afraid or too biased to engage ERMI at all. In either case, those with CIRS suffer greatly from this failure to fully engage the benefits of ERMI.

What you don’t see from any of these wayward inspectors is an attempt to discredit the ERMI methodology itself. After all, the testing was developed by the EPA and has a 99.7% accuracy. If you send in a sample, any quality lab like MycoMetrics will determine the exact amount of DNA present for each of the 36 molds scored on the ERMI report. The science behind the DNA methodology is rock solid.

What these inspectors drone on about are facts like the original testing was done on carpeting of homes and the fact that there was never an official release as to the meaning that could be assigned to given results. In Mold Testing – A Better Way, I describe how to circumvent nearly all the concerns related to testing methodology. This is done by comparing side-by-side outdoor and indoor mold samples. Using this method, we can readily determine if a building has a mold issue. It doesn’t matter if the building doesn’t have carpeting, is newer, or has a contributing outdoor source. All it takes is a little common sense and a desire to actually help those with CIRS to realize this.

In terms of what levels cause health issues, I refer you to ERMI & Politics. Dr. Shoemaker has meticulously collected ERMI scores and correlated it with patients that suffer from CIRS. In general, if the ERMI is above 2, those with CIRS will suffer. Alternatively, if the HERTSMI-2 score is above 11, those with CIRS must stay out. He has thousands of records to back up this claim. Granted there is a gray area for those that don’t have CIRS, but for those of us that are literally dying an excruciating death from mold toxins, it is an absolute travesty to not use ERMI to the fullest as I and Greg Weatherman have outlined.


Side-by-Side Out & Indoor Swiffer Sampling Detects Toxic Indoor Mold

ERMI Pictorial


Refining ERMI Testing

An ERMI mold report lists 36 mold scores expressed as the number of mold spores found in each milligram of dirt. These 36 molds are divided into two categories, Group I and Group II. There are 26 molds in Group I that consist of molds commonly found inside water-damaged buildings. There are 10 molds in Group II that consist of molds almost exclusively found outside. In the picture, I’ve depicted the movement of outdoor airborne debris into a building. Along with this outdoor debris, the building itself always produces some of it’s own internal dust and dirt.

Not surprisingly, outdoor airborne debris consists of molds from Group I, Group II, and various types of dust and dirt. In other words, given the wide range of decaying matter and conditions outside, there will always be some Group I molds and some Group II molds mixed in with various bits of dust and dirt. In the picture, this debris lands in the containers set out specifically to collect airborne debris. One container is outside and the other is inside. Even though it’s all mixed together in real life, I’ve separated the various constituents to help visualize the relative ratios. (You can read details of how I recommend collecting samples in Mold Testing – Improved Swiffer Cloth Method.)

When windows and doors are opened, a fraction of this mix of outdoor airborne debris enters the building. Although the amount of this debris is much less inside, the overall ratios of the Group I, Group II, and dirt entering from outside remains the same. In the picture, I’ve reduced the width of the indoor container while keeping the heights of the outdoor dust/dirt and Group II molds the same to indicate there is less debris indoors but some ratios remain the same. Specifically, if you compare the height of the green Group II molds to the height of the dark brown outdoor dust and dirt, they remain the same. This is true regardless of the overall amount of airborne debris that gets in through the windows and doors and regardless of whether the building has water damage.

It’s also helpful to realize that the occupants and items inside the building produce their own dust and debris. Furniture, people, pets, and so on all produce dust and debris. I’ve shown this as a layer of lighter colored brown dust and dirt in the inside container. In a home that doesn’t have any water damage, this indoor dust and debris is free of any additional mold spores. In a moldy home like the one shown, it will also have various Group I molds mixed in too. Although it’s not a critical point, the addition of indoor dust and dirt will lower (dilutes) the values listed on the indoor ERMI report. This relates to the fact that ERMI scores are listed as the number of mold spores per unit of dirt (milligram).

Getting back to the example, even though the amount of Group II molds and outdoor dirt entering the building will be less, the ratio of the Group II molds compared to dust and dirt levels will be unaffected by any Group I molds. Regardless of whether the building is moldy or not, Group II molds relative to dust and dirt amounts remains unaffected. This is due to the fact that buildings just don’t make outdoor Group II molds even if they’re water damaged. This is a key point. By establishing the ratio of outdoor Group II molds to indoor Group II molds, we have a point of reference to determine if any Group I molds are in excess. If we find that one or more Group I molds are not in the same ratio as the Group II molds, the only way that this can happen is if the building is producing Group I molds. In other words, the building is moldy.

Said again, The key to why collecting and comparing an outdoor Swiffer sample to an indoor Swiffer sample (see Improved DNA Testing) lies in the fact that the ratio of outside Group II mold counts compared to inside Group II mold counts can be used to determine if any of the Group I molds are in excess – if the building is moldy. In the example below, the ratio of outdoor Group II mold counts compared to indoor Group II counts is roughly 10:1. However, the ratio of some outdoor to indoor Group I molds are significantly less than 10:1. Where did these extra Group I molds come from that lowered the 10:1 ratio? We know they didn’t come from outdoors. Therefore, they must have come from within the building itself as a result of water damage. The building is moldy.

Abbreviated Moldy Building ERMI

Outdoor Swiffer Sample (spores/mg) Indoor Swiffer Sample (spores/mg) Outdoor/Indoor Ratio
Group I: Wallemia Sebi – 1800 Group I: Wallemia Sebi – 930
Group I: Aspergillus Niger – 400 Group I: Aspergillus Niger – 420
Group I: Stachybotrys Chartarum – 12 Group I: Stachybotrys Chartarum – 1
Group II: Alternaria Alternate – 9000 Group II: Alternaria Alternate – 860
Group II: Cladosporium – 7000 Group II: Cladosporium – 680
Group II: Mucor Aamphibiorum – 300 Group II: Mucor Amphibiorum – 29
The average ratio of indoor-to-outdoor Group II molds is 10:1.
This ratio is much lower for two Group I molds indicating the building has water damage.

Does this mean that if you only took a single ERMI sample that the results are useless? Certainly not – see ERMI Basics. In most cases, a single ERMI is quite telling. However, in some situations that I discuss in Mold Testing, the results can infrequently be misleading. A single ERMI is better suited to determine if a building is OK for those with CIRS to occupy. Side-by-side testing is better for determining if the building has water damage and also eliminates troublesome variables. Equally important, this is an attempt to bring some clarity to all those mold inspectors that just can’t seem to be able to wrap their minds around the fact that ERMI can be used to tell if any building is moldy both before and after remediation. The common sense logic is irrefutable.

6 thoughts on “ERMI NaySayers

  1. The problem I found with the results is that there is no quantifiable levels or value range of what is acceptable to normal. What is the tipping point? We know for people with CIRS the value of an ERMI and that it should be less than 2 but unlike say a blood analysis or air/surface testing there is nothing on the ERMI report to indicate how good or bad the reported levels are. This makes it very difficult to present in any sort of litigation or housing/tenancy tribunals as evidence therefore diminishing it’s evidentiary and seemingly scientific validity to the wider community.

    I think of it as a first test to see if there IS a problem especially when the mould, mycotoxins and water damage may not be visible – particularly in our case after been masked with repairs (not remediation) and fresh paint prior to moving in. If it comes back with unacceptable levels – for those with CIRS >2… for ‘normal’ people > ??? –

    Then I recommend spending more time and money for ‘old school’ testing of air and surface sampling to know exactly which rooms are more problematic as opposed to the overall snapshot of the ERMI s most people can’t afford an ERMI per room versus the costs of air-o-cells and surface slides. These are also more likely to hold up legally.

    • Amanda,

      That’s nicely stated. All testing has its limitations. Even in doing side-by-side indoor and outdoor ERMIs, if only a couple molds come slightly high, is there a problem? Also, as you noted, even if the home has a level of water damage, when is it really problematic for non-CIRS people? My personal feeling is that the levels even for those without CIRS are fairly low before health is compromised – see Moldy Versus Bad for Your Health. Some of these questions Inspectors can get better at answering with enough experience and by paying attention to details. For instance, my understanding is that each area of the country has its various molds that typically show up when there is water damage. If the mold in question isn’t one of these common players, then perhaps the slightly elevated level isn’t an issue. It’s these gray areas where a quality Inspector can really make a difference.

      Having said this, I really appreciate your input regarding legal matters. CIRS is a costly illness financially and otherwise. If we don’t begin to make our presence in the courts, I suspect very little will ever change. What I find interesting is that from my understanding, spore traps levels that are considered hazardous are somewhat dubious too. For example, the National Allergy Bureau Mold Chart indicates that counts up to 6,499 spores/m^3 are considered “low” mold levels. We all know that if we’re talking about Aspergillus/Penicillium there is a serious issue and if it is Stachybotrys then start running. Anyway, I don’t have any exposure to the legal side of mold testing so your input is very welcomed. Also, using additional tools to pinpoint the mold source after ERMI comes back indicating there is an issue makes total sense.

      You sound like maybe you’re an inspector yourself?

      • Thanks Greg… and as for being a Mould Inspector? Good Gracious NO! I am someone who had learned through the school of hard knocks. I am a tenant whose family was slowly poisoned for the last 2 years as my Realtor and Landlord did not take my concerns about multiple points of water egress seriously. A toilet not fixed to the floor apparently was of no concern. Water running internally down walls (and unbeknownst to me INSIDE those walls) in heavy rain was again of no concern. In fact they suggested that I should be paying more per week to live this way. Once we did the ERMI (overall results were 25.1 – Stachybotrys 32,000) and realized we had a serious problem but that I knew this test was not quantifiable that I sought out a fabulous mycologist to help gather evidence especially what is in that wall cavity.

        The Landlords and Leasing Agent’s aim was to discredit me and offered no help with remediating my personal property in an effort to mitigate their accountability. Everything we own has been put in to storage. They also don’t understand the severity of what has happened so they are selling the property but giving it a cosmetic overhaul but not attending to the structural defects or proper remediation. The selling Agent specifically asked if this problem was something that could be picked up on a purchaser building inspection and I said probably not – only perhaps moisture levels but certainly not the reality of contamination that was scientifically proven to be behind those walls and the mycotoxins throughout the entire building. I said if they didn’t PROPERLY remediate or declare it as part of the contract of sale then it was in my mind bordering on criminal neglect. I pity the new owners or tenants – they will have no idea what dangers the ‘nice normal looking home’ presents. Many of us don’t and now I am looking for another rental. How do I quickly assess the true danger of a property to our now very weakened immune state? ERMI’s sent to the US take too long as properties are snapped up within hours. So I just use my newly honed common sense filter quite literally with mouldy eyes and look closely (or avoid) – most ground floor dwellings, particularly those on a sloping block or any with flat roofs and anything with any sign of previous water damage even if I am assured it has been rectified.

        So out of this adversity I am committed to raising awareness about Mould, the dangers both in terms of health and personal property but more importantly some statutory ACCOUNTABILITY once these issues are uncovered in property. I contacted the Australian EPA, our local city council Environmental Officer and the Dept of Health and they have no real awareness, willingness or ability to do anything. And that sucks. Australian awareness about Mould/Mycotoxins is increasing as people finally understand what is the underlying cause of their illnesses. We have a long way to go but more Doctors are starting to train with Dr Shoemaker (most mainstream GP’s are totally clueless though and I had one suggest I needed to see a psychiatrist because of my mould story), we are starting to litigate and look very closely at the US research and case law to help guide us.

        Can I also say that your website is an amazing resource for us Aussies. I constantly refer mould newbies here to better understand what it is and how to deal with it and we share your thoughts and content links across our amazing FB group as well. So a huge Thank You!

        • Wow, stachy at 32,000 is wicked. I wish there was a quick test for mold but alas, we’ll have to wait.

          Regarding quickly assessing a building, here are a few ideas related to finding hidden mold and a bit of what I consider to be the best mold-free construction practices.

          1. Is it well maintained?
          2. What do other tenants say about upkeep?
          3. Does it have a big overhang and steep roof?
          4. Is a foundation a slab-on-grade with a good 6″ of foundation above grade?
          5. Does the ground pitch away from the building on all sides?
          6. Are the roof lines simple and does it have any signs of decay at intersections and corners?
          7. Is the siding maintained and are the gutters directing water well away from the building?
          8. Are there any signs of decay inside sink cabinetry?
          9. Is the underside of the toilet tank cover and between the tank and wall mold free?
          10. Are the ceilings stain free? Are the ceilings freshly painted and if so, why?
          11. Is the shower/tub surround modular (single piece)?
          12. Is the furnace filter clean?
          13. Is the A/C drip pan clean?
          14. Using a flashlight to look through grills, does it look clean inside the duct work?
          15. Is the apartment well away from Smart Meters?

          The list goes on but I think I’ll stop with a link to an article by Andrea that I commented on.

          Guidelines for Buying or Renting a Home

          All the best and thanks for the nice comment about the site.

  2. I understand the logic behind your testing but I still don’t get it. If the numbers are higher outside than the inside then even if you got your building safe, you still couldn’t live in that area or at least you couldn’t go outside . The illness isn’t going to differentiate where you got the toxins. If my building is safe but my numbers are high outside will I get any better?

    • Congratulations! This is actually a bit of a difficult subject to state clearly. In reality, we’re comparing ratios of ratios using the side-by-side indoor and outdoor mold testing so I don’t think this is an easy concept – it took me a while to get anyway.

      Granted, if the mold counts are high outside (especially Group I molds that are particularly problematic), this isn’t the best of situations. You know some percentage of this will end up in your house. However, Dr. Shoemaker has argued that Group I molds that live outdoors have to expend so much energy dealing with the elements and competing microbes, that they simply don’t have the resources to produce many mycotoxins. On the other hand, molds that grow indoors are well protected from temperature extremes, inclement weather, sunlight, and much of the competition. In these idyllic conditions, mycotoxins are produced in abundance. This is their way of putting up a “keep out” sign against other competing molds and bacteria.

      Having said this, I and many others know full well you can get a mold hit from outside sources. There are low lying areas near my house that I dare not go except for the dead of winter. I have a harder time in fall in part because mold counts are much higher out in the country where I live. Lisa Petrison from Paradigm Change is a strong believer in avoiding these outdoor sources and in a perfect world, we would all move to dryer climates with lower outdoor mold counts.

      Nonetheless, I have recovered a good portion of my health and continue to improve even though my indoor Group I molds are higher than most simply from the infiltration from the moldy woods that surround the house. As mentioned in Sleep Sanctuary, I use pleated window filters when letting “fresh air” in on a daily basis and run a couple HEPA filters in the house to reduce the indoor load.

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