Background

The homeowner is a 64-year-old man who complains of chronic sinus and respiratory issues while in his home. The symptoms subside when he leaves the home for an extended period of time. His children, who are adult age and do not live with him, noticed that every time they visit they leave the home with a musty smell on their clothes. Concerned about the potential of an unusual mold condition within his home, the homeowner contracts with CMI.

Initial Inspection & Testing

CMI performs a comprehensive assessment of the entire home. Mold contamination is detected in the basement, ambient living areas, and the attic. The basement is unfinished and the foundation walls and wood framing members are exposed. The contamination within the basement was observed on exposed ceiling sheathing, joists, and contents throughout the entire basement.

The HVAC unit is located in the basement area. It was replaced by the homeowner approximately 4 years prior to the inspection. However, its original and installed when the home was built about 30 years ago. Within the ambient living areas, mold was detected on most of the contents throughout the entire first-floor living area. Within the attic, mold contamination was detected on the attic roof decking and rafters.

This case study will demonstrate the following points:

1. Spore count concentration used in clearance does not necessarily mean the environment is cleaned of mycotoxins.

2. The presence of certain populations of mold spores is important to identify and is a relevant indicator of the potential presence of mycotoxins.

3. Low spore count concentrations, or what is perceived to be a comparable concentration to outside controls, does not mean the environment is clean of mycotoxins.

4. Due to the difficulty in reaching interstitial areas within the HVAC system and associated ducts and returns, it is improbable to thoroughly clean the HVAC system and associated ducts and returns once they have contaminated with mold and mycotoxins.

Initial Samples

The first sampling set employed used air and surface samples within the ambient living areas, basement, and attic; The results are as follows;

The results of the air samples collected in the first-floor ambient living area and upstairs master bedroom area were slightly elevated with Aspergillus / Penicillium relative to the outside reference sample.

The Outside, Main Floor, and Master Bedroom Air Samples

Sample LocationOutsideMain FloorMaster Bedroom
Spore TypeRaw CountCount. m2% Of TotalRaw CountCount. m2% Of TotalRaw CountCount. m2% Of Total
Aspergillus/ Penicillium31005029047.4
Basidiospores110514021.1
Cladosporium29045
Myxomycetes++11050
Pithomyces14021.1
Rust1105.3
Unidentifiable Spores1105.3
Arthrinium11050
TOTAL FUNGI22010062001006190100
Hyphal Fragment11050
Sensitivity 600x444444

The Basement and Attic Air Samples

Sample LocationBasementAttic
Spore TypeRaw CountCount. m2% Of TotalRaw CountCount. m2% Of Total
Alternaria31002
Ascospores1400.8
Aspergillus/ Penicillium44190091.32193018.6
Basidiospores2904.373006
Cladosporium2904.370310061.9
Epicoccum1400.8
Ganoderma31002
Myxomycetes++42004
Pithomyces2901.8
Rust1100.2
Arthrinium2901.8
Pestalotia1100.2
TOTAL FUNGI4820801001165010100
Hyphal Fragment1357011.4
Sensitivity 600x4444

Surface Sample From Attic Roof Decking

Spore TypeCategory
Aspergillus/ PenicilliumLow
CladosporiumHigh
PollenRare

Surface Sample From Basement Ceiling Joints and Dining Room

BasementDining
Spore TypeCategoryCategory
AscosporesLow
CurvulariaRare
EpicocummRare
Myxomycetes++Rare

EPA 36 Sample From HVAC Systems and Air Ducts (Group 1)

Group 1HVACMain
Spore IDSwabSwab
Aspergillus Fumigatus38
Aspergillus ochraceus2,610213
Aspergillus Versicolor3,966
Eurotium Amstelodami++26622
Chaotomium Globosum1,540702
Aureobasidium pullulans721909
Cladosporium spaerospermum13,98531,318
Paecilomyces variotii19
Pencillium Brevicompactum18,600171
Pencillium Corylophilum1,641
Pencillium purprogenum15
Pencillium variabile4
Scopulariopsis brevicaulis48
Scopulariopsis chartarum27
Wallemia Sebi668139
TOTAL44,14933,474

EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)

Group 2HVACMain
Spore IDSwabSwab
Alternaria alternata886339
Aspergillus ustus8,352726
Cladosporium cladosporioides 112,312739
Cladosporium cladosporioides 270111
Cladosporium herbarum75
Epicoccum nigrum59,38018,470
Mucor and Rhizopus group1
Penicillium chrysogenum13
TOTAL81,09720,385

Recommendations for Next Steps

Due to the severity of the health issues with the homeowner, the population of molds detected in the HVAC system/associated ducts and returns, it was advised to remove the HVAC system and ductwork. However, the homeowner did not want to replace the system and had a cleaning of the system and ducts performed instead.

Post Remediation Verification Sampling of the HVAC system was declined by the client saying he felt because it was cleaned and should suffice. A month after everything was cleaned the homeowner was still experiencing adverse health issues while in the home. He felt more symptoms when the HVAC system was running. As a result, further testing was performed in the HVAC system.

Post Test 1

Post-remediation verification testing results performed in April of 2014 were the following;  

The Outside, Main Floor, and Master Bedroom Air Samples

Sample LocationOutsideBasementMain Floor
Spore TypeRaw CountCount. m2% Of TotalRaw CountCount. m2% Of TotalRaw CountCount. m2% Of Total
Ascospore1408.3
Basidiospores28028.6
Cladosporium940083.3420071.4
Myxomycetes++1408.3
TOTAL FUNGI114801006280100n/a

The Hallway and Attic Air Samples

Sample LocationHallwayAttic
Spore TypeRaw CountCount. m2% Of TotalRaw CountCount. m2% Of Total
Cladosporium280100
TOTAL FUNGIn/a280100
Sensitivity 600x4242

The surface samples came back from the basement ceiling joists and attic rafter none detected.

Based on traditional accepted Post  Remediation Results, PRV air and results would be considered and suggest that the home was within a normal fungal ecology and or condition one state.  The HVAC system was not replaced as suggested.

However,  according to the homeowner, the HVAC system and associated ducts and returns were cleaned. Post Remediation Verification Sampling of the HVAC system was declined by the client saying he felt because it was cleaned and should suffice.

Post Test 2

A month after everything was cleaned the homeowner was still experiencing adverse health issues while in the home.   He felt more symptoms when the HVAC system was running. As a result, In May of 2014 further testing was performed in the HVAC  system. A spore trap was placed in the main supply duct line to measure potential mold spore concentrations coming out of the system.      

Additionally,  both composite regular  Microscopy (swab sample)  and MsQPCR based on the ERMI panel of mold species were  collected from the HVAC filter, inside the main duct line, supplies, and returns;  The results were as follows:

Spore Types Raw CountCount/m% of TotalRaw CountCount/m³% of Total
Alternaria1* 10*0.1
Ascospores47200016.2
Basidiospores2431030083.4
Cladosporium1400.3140100
Total Fungi29212350100140100
Hyphal Fragment1400.3
Pollen38160013
Analyt. Sensitivity 600x4242
Analyt. Sensitivity 300x1313
Skin Fragments (1-4)11
Fibrous Particulate (1-411

In the above results, only one total spore count was detected from the main duct system. Background debris appears to be cleaned. However, the surface sample results from both the basic microscopy and EPA 36 still detect mold spores from several mold genera,

HVAC
Spore TypeCategory
AlternariaRare
AscosporesRare
BasidiosporesLow
GanodermaRare
Myxomycetes++Rare
ScopulariopsisRare
PithomycesRare
Hyphal Fragment Rare
Insect FragmentRare

EPA 36 Sample From HVAC Systems (Group 1)

Group 1HVAC
Spore IDSwab
Aspergillus veriscolor227
Eurotium amstelodami31
Scopulariopsis brevicalulis12
Scopulariopsis chartarum13
TOTAL282

EPA 36 Sample From HVAC Systems (Group 2)

Group 2HVAC
Spore IDSwab
Mucor and Rhizopus Group1,284
TOTAL1,284

It was suggested again to the homeowner to replace the HVAC system and associated ducts and returns. Nothing was done for several months, However, the homeowner decided to have the system cleaned again by a different company. This time the company employed removed the fiberglass insulation and removed the motor to clean and sanitize. The coils were not removed. The ducts and returns were cleaned again.

Post Test 3

In December, the client was still experiencing adverse health issues after the system was cleaned. The client requested to sample in the Ambient living area – Family room and an EPA 36 surface and Mycotoxin samples within the HVAC system that was cleaned for the 2nd time.

After the system was cleaned twice.  The first time was a basic cleaning of the ducts and the second was a complete cleaning where the motor was removed and cleaned.   The coils were not removed. What is evident is that the second cleaning actually disturbed the spores harbored throughout the system and actually caused more distribution of both mold and mycotoxins through the duct system.  Below is what the Ductwork looks like after cleaning.

Air Sample Result – Family Room

Spore TypesRaw CountCount/m³% of TotalRaw CountCount/m³% of Total
Ascospore1 206.3172
Aspergillus/Penicillium15 31086.8
Basidiospores820062.5 1205.6
Cladosporium24012.51205.6
Myxomycetes++24012.5
Bispora1206.3
Total Fungi14320 10018357100

EPA 36 Results from the HVAC system and Associated ducts,

supplies and returns;

Group 1HVAC
Spore IDSwab
Aspergillus niger2
Aspergillus penicillioides41
Aspergillus sclerotoirum2
Aspergillus Versicolor116
Eurotium Amstelodami++121
Chaotomium Globosum13
Aureobasidium pullulans220
Cladosporium spaerospermum1,614
Scopulariopsis brevicaulis11
Scopulariopsis chartarum3
Wallemia Sebi601
TOTAL3,087

EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)

Group 2HVAC
Spore IDSwab
Alternaria alternata3
Aspergillus ustus166
Cladosporium cladosporioides 1445
Cladosporium cladosporioides 23
Cladosporium herbarum2
Epicoccum nigrum970
Mucor and Rhizopus group75
Penicillium chrysogenum2
TOTAL1,666

Mycotoxin Sample results are as follow

The results of the air sample detected elevated mold spore counts of Pencillium / Aspergillus.   Additionally a somewhat important indicated was the background debris was a 2 vs. 1 compared to outdoors.   Background debris is dirt and dust in the air. The results of the EPA 36 show several mold genera. Also, the Mycotoxin sample detected the Presence Of Trichothecenes. The results indicate that there is still mold contamination within the HVAC System and associated ducts and returns.  

Post Test 4

Once the system was cleaned again, both an EPA  36 and Mycotoxin was collected from the HVAC system and associated ducts and returns. The  results of the EPA 36 and Mycotoxin were as follows:

EPA 36 Results from the HVAC system and Associated ducts,

supplies and returns;

Group 1HVAC
Spore IDSwab
Aspergillus niger1
Aspergillus penicillioides5
Aspergillus Versicolor57
Eurotium Amstelodami++1
Chaotomium Globosum13
Aureobasidium pullulans2,466
Cladosporium spaerospermum441
Penicillium brevicompactum99
Stachybotrys Chartarum3
Wallemia Sebi9
TOTAL3,066

EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)

Group 2HVAC
Spore IDSwab
Alternaria alternata5
Aspergillus ustus19
Cladosporium cladosporioides 1367
Cladosporium cladosporioides 22
Epicoccum nigrum252
TOTAL645

Mycotoxin Sample results are as follows;

Conclusion

The population of molds detected in the HVAC system- associated ducts and returns, with the EPA 36, it was advised to ensure the removal of all potential distribution sources the HVAC system and ductwork be replaced. The final EPA 36 and Mycotoxin still detected the presence of several mold general in the EPA 36. Stachybotrys was still detected. Additionally, mycotoxins were still detected in the system. Although lower concentrations, it is probable that both the spores and mycotoxins are still harboring within interstitial areas within the system that cannot be reached. It is improbable to thoroughly clean the HVAC system and associated ducts and returns once they have contaminated with mold and mycotoxins.

1. Spore count concentration used in clearance does not necessarily mean the environment is cleaned of mycotoxins.

2. The presence of certain populations of mold spores is important to identify and is a relevant indicator of the potential presence of mycotoxins.

3. Low spore count concentrations, or what is perceived to be a comparable concentration to outside controls, does not mean the environment is clean of mycotoxins.

4. Due to the difficulty in reaching interstitial areas within the HVAC system and associated ducts and returns, it is improbable to thoroughly clean the HVAC system and associated ducts and returns once they have contaminated with mold and mycotoxins.