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 Location | Outside | Main Floor | Master Bedroom | ||||||
| Spore Type | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total |
| Aspergillus/ Penicillium | – | – | – | 3 | 100 | 50 | 2 | 90 | 47.4 |
| Basidiospores | – | – | – | 1 | 10 | 5 | 1 | 40 | 21.1 |
| Cladosporium | – | – | – | 2 | 90 | 45 | – | – | – |
| Myxomycetes++ | 1 | 10 | 50 | – | – | – | – | – | – |
| Pithomyces | – | – | – | – | – | – | 1 | 40 | 21.1 |
| Rust | – | – | – | – | – | – | 1 | 10 | 5.3 |
| Unidentifiable Spores | – | – | – | – | – | – | 1 | 10 | 5.3 |
| Arthrinium | 1 | 10 | 50 | – | – | – | – | – | – |
| TOTAL FUNGI | 2 | 20 | 100 | 6 | 200 | 100 | 6 | 190 | 100 |
| Hyphal Fragment | 1 | 10 | 50 | – | – | – | – | – | – |
| Sensitivity 600x | – | 44 | – | – | – | 44 | – | 44 | – |
The Basement and Attic Air Samples
| Sample Location | Basement | Attic | ||||
| Spore Type | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total |
| Alternaria | – | – | – | 3 | 100 | 2 |
| Ascospores | 1 | 40 | 0.8 | |||
| Aspergillus/ Penicillium | 44 | 1900 | 91.3 | 21 | 930 | 18.6 |
| Basidiospores | 2 | 90 | 4.3 | 7 | 300 | 6 |
| Cladosporium | 2 | 90 | 4.3 | 70 | 3100 | 61.9 |
| Epicoccum | – | – | – | 1 | 40 | 0.8 |
| Ganoderma | – | – | – | 3 | 100 | 2 |
| Myxomycetes++ | – | – | – | 4 | 200 | 4 |
| Pithomyces | – | – | – | 2 | 90 | 1.8 |
| Rust | – | – | – | 1 | 10 | 0.2 |
| Arthrinium | – | – | – | 2 | 90 | 1.8 |
| Pestalotia | – | – | – | 1 | 10 | 0.2 |
| TOTAL FUNGI | 48 | 2080 | 100 | 116 | 5010 | 100 |
| Hyphal Fragment | – | – | – | 13 | 570 | 11.4 |
| Sensitivity 600x | – | 44 | – | – | 44 | – |
Surface Sample From Attic Roof Decking
| Spore Type | Category |
| Aspergillus/ Penicillium | Low |
| Cladosporium | High |
| Pollen | Rare |
Surface Sample From Basement Ceiling Joints and Dining Room
| Basement | Dining | |
| Spore Type | Category | Category |
| Ascospores | Low | – |
| Curvularia | – | Rare |
| Epicocumm | – | Rare |
| Myxomycetes++ | – | Rare |
EPA 36 Sample From HVAC Systems and Air Ducts (Group 1)
| Group 1 | HVAC | Main |
| Spore ID | Swab | Swab |
| Aspergillus Fumigatus | 38 | – |
| Aspergillus ochraceus | 2,610 | 213 |
| Aspergillus Versicolor | 3,966 | – |
| Eurotium Amstelodami++ | 266 | 22 |
| Chaotomium Globosum | 1,540 | 702 |
| Aureobasidium pullulans | 721 | 909 |
| Cladosporium spaerospermum | 13,985 | 31,318 |
| Paecilomyces variotii | 19 | – |
| Pencillium Brevicompactum | 18,600 | 171 |
| Pencillium Corylophilum | 1,641 | – |
| Pencillium purprogenum | 15 | – |
| Pencillium variabile | 4 | – |
| Scopulariopsis brevicaulis | 48 | – |
| Scopulariopsis chartarum | 27 | – |
| Wallemia Sebi | 668 | 139 |
| TOTAL | 44,149 | 33,474 |
EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)
| Group 2 | HVAC | Main |
| Spore ID | Swab | Swab |
| Alternaria alternata | 886 | 339 |
| Aspergillus ustus | 8,352 | 726 |
| Cladosporium cladosporioides 1 | 12,312 | 739 |
| Cladosporium cladosporioides 2 | 70 | 111 |
| Cladosporium herbarum | 75 | – |
| Epicoccum nigrum | 59,380 | 18,470 |
| Mucor and Rhizopus group | 1 | – |
| Penicillium chrysogenum | 13 | – |
| TOTAL | 81,097 | 20,385 |
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 Location | Outside | Basement | Main Floor | ||||||
| Spore Type | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total |
| Ascospore | 1 | 40 | 8.3 | – | – | – | – | – | – |
| Basidiospores | – | – | – | 2 | 80 | 28.6 | – | – | – |
| Cladosporium | 9 | 400 | 83.3 | 4 | 200 | 71.4 | – | – | – |
| Myxomycetes++ | 1 | 40 | 8.3 | – | – | – | – | – | – |
| TOTAL FUNGI | 11 | 480 | 100 | 6 | 280 | 100 | n/a | – | – |
The Hallway and Attic Air Samples
| Sample Location | Hallway | Attic | ||||
| Spore Type | Raw Count | Count. m2 | % Of Total | Raw Count | Count. m2 | % Of Total |
| Cladosporium | – | – | – | 2 | 80 | 100 |
| TOTAL FUNGI | n/a | – | – | 2 | 80 | 100 |
| Sensitivity 600x | – | 42 | – | – | 42 | – |
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 Count | Count/m | % of Total | Raw Count | Count/m³ | % of Total |
| Alternaria | 1* | 10* | 0.1 | – | – | – |
| Ascospores | 47 | 2000 | 16.2 | – | – | – |
| Basidiospores | 243 | 10300 | 83.4 | – | – | – |
| Cladosporium | 1 | 40 | 0.3 | 1 | 40 | 100 |
| Total Fungi | 292 | 12350 | 100 | 1 | 40 | 100 |
| Hyphal Fragment | 1 | 40 | 0.3 | – | – | – |
| Pollen | 38 | 1600 | 13 | – | – | – |
| Analyt. Sensitivity 600x | – | 42 | – | – | 42 | – |
| Analyt. Sensitivity 300x | – | 13 | – | – | 13 | – |
| Skin Fragments (1-4) | – | 1 | – | – | 1 | – |
| Fibrous Particulate (1-4 | – | 1 | – | – | 1 | – |
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 Type | Category |
| Alternaria | Rare |
| Ascospores | Rare |
| Basidiospores | Low |
| Ganoderma | Rare |
| Myxomycetes++ | Rare |
| Scopulariopsis | Rare |
| Pithomyces | Rare |
| Hyphal Fragment | Rare |
| Insect Fragment | Rare |
EPA 36 Sample From HVAC Systems (Group 1)
| Group 1 | HVAC |
| Spore ID | Swab |
| Aspergillus veriscolor | 227 |
| Eurotium amstelodami | 31 |
| Scopulariopsis brevicalulis | 12 |
| Scopulariopsis chartarum | 13 |
| TOTAL | 282 |
EPA 36 Sample From HVAC Systems (Group 2)
| Group 2 | HVAC |
| Spore ID | Swab |
| Mucor and Rhizopus Group | 1,284 |
| TOTAL | 1,284 |
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 Types | Raw Count | Count/m³ | % of Total | Raw Count | Count/m³ | % of Total |
| Ascospore | 1 | 20 | 6.3 | 1 | 7 | 2 |
| Aspergillus/Penicillium | – | – | – | 15 | 310 | 86.8 |
| Basidiospores | 8 | 200 | 62.5 | 1 | 20 | 5.6 |
| Cladosporium | 2 | 40 | 12.5 | 1 | 20 | 5.6 |
| Myxomycetes++ | 2 | 40 | 12.5 | – | – | – |
| Bispora | 1 | 20 | 6.3 | – | – | – |
| Total Fungi | 14 | 320 | 100 | 18 | 357 | 100 |
EPA 36 Results from the HVAC system and Associated ducts,
supplies and returns;
| Group 1 | HVAC |
| Spore ID | Swab |
| Aspergillus niger | 2 |
| Aspergillus penicillioides | 41 |
| Aspergillus sclerotoirum | 2 |
| Aspergillus Versicolor | 116 |
| Eurotium Amstelodami++ | 121 |
| Chaotomium Globosum | 13 |
| Aureobasidium pullulans | 220 |
| Cladosporium spaerospermum | 1,614 |
| Scopulariopsis brevicaulis | 11 |
| Scopulariopsis chartarum | 3 |
| Wallemia Sebi | 601 |
| TOTAL | 3,087 |
EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)
| Group 2 | HVAC |
| Spore ID | Swab |
| Alternaria alternata | 3 |
| Aspergillus ustus | 166 |
| Cladosporium cladosporioides 1 | 445 |
| Cladosporium cladosporioides 2 | 3 |
| Cladosporium herbarum | 2 |
| Epicoccum nigrum | 970 |
| Mucor and Rhizopus group | 75 |
| Penicillium chrysogenum | 2 |
| TOTAL | 1,666 |
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 1 | HVAC |
| Spore ID | Swab |
| Aspergillus niger | 1 |
| Aspergillus penicillioides | 5 |
| Aspergillus Versicolor | 57 |
| Eurotium Amstelodami++ | 1 |
| Chaotomium Globosum | 13 |
| Aureobasidium pullulans | 2,466 |
| Cladosporium spaerospermum | 441 |
| Penicillium brevicompactum | 99 |
| Stachybotrys Chartarum | 3 |
| Wallemia Sebi | 9 |
| TOTAL | 3,066 |
EPA 36 Sample From HVAC Systems and Air Ducts (Group 2)
| Group 2 | HVAC |
| Spore ID | Swab |
| Alternaria alternata | 5 |
| Aspergillus ustus | 19 |
| Cladosporium cladosporioides 1 | 367 |
| Cladosporium cladosporioides 2 | 2 |
| Epicoccum nigrum | 252 |
| TOTAL | 645 |
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.