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Forensic Analytical. Mold Litigation Perspectives. Presented by: Ben Kollmeyer, MPH, CIH Forensic Analytical Consulting Services CIHC – December 5, 2006. Overview. The Case of the Phantom Mold Common Issues PCR: A Better Mousetrap?.

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Forensic Analytical

Mold Litigation Perspectives

Presented by:

Ben Kollmeyer, MPH, CIH

Forensic Analytical Consulting Services

CIHC – December 5, 2006


Overview

  • The Case of the Phantom Mold

  • Common Issues

  • PCR: A Better Mousetrap?


The Case of the Phantom Mold:Carpet Microvacuum Results in a Litigated Manner


Background

  • Teacher alleges various injuries caused by environmental conditions at a school.

  • Suit against school dismissed (worker’s compensation as exclusive remedy).

  • Focus shifts to school builders and suppliers.

  • Focus shifts to mold and mycotoxins.


Environmental Setting

  • School set in an arid climate.

  • Rooms arranged around a central quad with exterior entrances.

  • Teacher predominately spent time in two classrooms, 4 & 7. Predominately 7.

  • Room 4: slab on grade, sticks & bricks.

  • Room 7: modular at grade w/ crawlspace.

  • Focus of claims is on room 7.


Environmental Data

  • Visual observation by three different environmental consultants.

  • Air sampling by one consultant.

  • Microvacuum sampling by two consultants within 6 months of each other.

  • Tapelift and swab samples by two consultants.


Visual Findings Summary

  • Room 7

    • Standing water and biological growth in sub-grade crawlspace.

    • Evidence of exterior surface moisture and intrusion into entry.

    • No elevated moisture in carpet.

    • No visible mold.

  • Room 4

    • Mold at sink separator.

    • Mold behind baseboard.


Room 7


Room 4


Swab and Tapelift Samples

  • Confirm visual observations.

  • Others do not reveal elevated levels.

  • General agreement among consultants.


Air Sampling Summary

  • 2 locations in each room.

  • Viable and non-viable samples.

  • Variety of rooms other than 7 & 4.

  • 4 outdoor control controls.

  • Results do not show elevations in 4 or 7.

    • Generally lower than outdoors.

    • No different than other rooms.

  • General agreement among consultants.


Microvacuum Results

  • Consultant #1

    • cfu/100cm2

    • 8 samples from room 7.

    • 6 samples from room 4.

  • Consultant #2

    • cfu/g

    • 3 samples from room 7.

    • 3 samples from room 4.


Carpet Dust Studies

  • Chao, et al (Harvard Study)

    • Mycopathologia 154:93-106, 2001

  • Randomly selected office buildings.

  • Most strongly correlated w/ age of carpet:

    • Yeast

    • Coelomycetes

    • Aureobasidium

    • Non-sporulating


Carpet Dust Studies

  • Chew, et al

    • Allergy 58:13-20, 2003

  • Randomly selected homes.

  • Most common:

    • Non-sporulating, Penicillium, Yeast

  • More prevalent in dust than air:

    • Yeast, Eurotium, A. versicolor


Carpet Dust Studies

  • Horner, et al.

    • Applied & Environmental Microbiology 70:6394-6400, 2004

  • Non-problem homes.

  • Most common:

    • Cladosporium

    • Yeast

    • Penicillium


Carpet Dust Studies

  • Hicks, et al.

    • JOEH 2:481-492, 2005

  • Non-problem homes.

  • Most common, high traffic:

    • Cladosporium, Yeast, Penicillium, Aureobasidium

  • Most common, low traffic:

    • Cladosporium, Penicillium, Yeast


The Positions

  • Plaintiff focused on the presence of elevated levels of yeast with moisture under the building as the cause.

  • Defense found results to be typical of carpets and foot traffic patterns. Focused on moist grass outside of classrooms and lack of differences in sampling results between the two types of construction.


The Outcome

  • It settled before trial (of course).

  • Both sides equally unhappy (supposedly).


Interpretation of Mvac Results

  • Quantitative….less valuable

    • Extremely variable. Highly dependent upon how sample is collected.

    • Commonly used numerical values (i.e., 100K cfu/g) not very reliable.

    • Focus on comparative samples.


Interpretation of Mvac Results

  • Qualitative….more valuable

    • Compare to genera/species commonly found in non-problem buildings.

    • Compare to known growth reservoirs.

  • Visual….most valuable

    • If there is mold exposure, show me the mold.


Common Issues


CONSTRUCTIONMOLDSAMPLING

Common Issues

  • Mold is Gold?

  • Investigative Approach:

  • Specificity of Repair Recommendations:

    • “Remove ?? inches beyond affected materials.”

    • Methods…containment, PPE, etc.

    • DT protocols.

X


SOURCE PATHWAY EXPOSURE HEALTH EFFECTS

100% = “YES” “MAYBE” 0% = “NO”

Common Issues

  • Linkages to Causal Factors

  • Linkages to Health Effects

  • Reasonable Degree of Scientific Certainty


Common Issues

  • What Does the Future Hold?

    • “Damp Indoor Spaces & Health”

      • fungal spores? materials? mycotoxins? mVOCs?

      • bacteria?

      • dust mites?

      • allergens?

      • moisture?

      • sick people with lawyers?


PCR:A Better Mousetrap?


Mold Sampling Methods

  • Total airborne spores – “nonviable”

  • Viable airborne spores – “culturable”

  • Airborne mold spore equivalents – genetic material – PCR method


Nonviable Spore Counting

  • Limited ID at genus level only

    • Genera groupings become surrogates for individual species.

    • May be comparing apples to oranges…missing differences between species.

  • Short sampling times.

  • Fast TAT (hours to days).

  • Relatively inexpensive.


Viable Culturing

  • Can provide identification to the species level, but is frequently too expensive and time consuming.

  • Viable mold spores only, misses non-viable spores. Furthermore, “viable” may not be “culturable”.

  • Short sampling time.

  • Long turn-around time.

  • Can be quite expensive to get species.

  • “Viable” may not be “culturable”

  • Long TAT


PCR Analysis

  • 24-hour speciation of viable and non-viable spores.

  • Instrument-based method with less subjectivity and more conducive to quality assurance procedures.

  • Sampling time constraints lifted, allowing for longer duration samples (e.g., 8-hour).

  • Must target a species or panel for analysis.

  • Optical microscopy and molecular genetics differ taxonomically.


Mold Analysis Methods

Spore Traps

Cultures

PCR


Putting PCR to Use

  • Characterize Sources

    • Non-viable assessment to ID key genera.

    • Collect a representative dust/bulk sample.

  • Non-viable methods to begin focusing panel. PCR analysis of source sample to see what responds.

  • Selection of “indicator” species.

  • Targeted analysis of long-term air samples.


Lessons from the Past: PCM

  • Surrogate Method (PCM): counts relatively large airborne fibers instead of airborne asbestos fibers, which are often too short and/or too thin ever to be counted by PCM

  • Surrogate Standard (PCM): Clearance at levels below 0.01 f/cc by PCM. Nearly assured not to have actually assessed airborne asbestos


Lessons from the Past: TEM

  • “The TEM method gives the most complete information on airborne asbestos: it can distinguish asbestos from other fibers and also is able to detect very thin fibers. However, it is expensive and time-consuming. TEM is not readily available.”– The EPA Purple Book, 1985


PCR: Looking Ahead

  • Back to IH Basics

    • 8-hour TWA sampling

    • reproducibility

    • personal air sampling

  • Changing the “No TLV for Mold” Paradigm

    • personal air sampling occupational exposures

    • epidemiology and linkage to health outcomes

    • movement away from I/O comparisons

  • Better Defined Standard of Practice

    • separating the IH from the overnight mold expert


  • Thank You!www.forensica.com


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