INDOOR ENVIRONMENTAL FUNGI CONTAMINATION PRIVATE RESIDENCE
FRANKLIN, MILWAUKEE COUNTY, WISCONSIN
The Wisconsin Department of Health and Family Services (DHFS) conducted a health hazard assessment for environmental mold at a private residence in Franklin, Milwaukee County,Wisconsin. The home recently received damage from strong winds and water. Because theresidents are worried the home is not habitable because of mold contamination, they vacated thehome. Almost all areas of the home are safe, but visible mold was noted in the basement, whichcould be a potential health hazard. Although visual inspections at other locations in the Franklinhome did not reveal any remarkable areas of visible mold growth, test results indicated the presenceof low to moderate levels of mold growth in other areas of the house. If those areas areappropriately remediated and the overall water intrusions issues corrected, the entire home should besafe for reoccupancy. The home's building materials were checked for residual moisture, but thelevels of moisture remaining in the materials did not indicate that the materials would promotesignificant mold growth. Residents can safely clean the mold on walls and windows by disinfectingthose areas with a household bleach solution. Of more significance is the fact that attic insulationcontains tremolite asbestos, which can present an inhalation exposure risk if disturbed.
The Franklin Health Department requested technical assistance from DHFS regarding the householdat 3229 West Franklin Terrace, Franklin, Milwaukee County, Wisconsin. DHFS staff havetechnical experience in assessing indoor air quality issues, including those situations related toenvironmental mold exposure. Because of the large number of indoor air quality inquiries andconcerns received each year by DHFS, activities and involvement is determined on a case-by-casebasis. The presence, type, severity of the health complaints, and number of persons affected aresome of the factors considered by DHFS when making such a determination.
Tornado-like winds and heavy rain damaged the Franklin home on July 2, 2000. The residencesustained wind damage to the exterior siding allowing water to penetrate the interior of the home (1,2). After this event, three children who lived in the home began to experience adverse respiratoryhealth effects when at home. Their symptoms improved when the family was away from the home. Later in July 2000, the homeowners vacated their home. The homeowners feel the adverse healtheffects are a result of exposure to environmental contaminants in their home, specifically mold,which grew as the result of water intrusion. At the end of July, contractors inspected the home todetermine the extent of damage and to estimate the cost of repair. At the end of August andSeptember, the home was inspected by two, independent environmental consulting firms (3, 4). Both firms identified moderate mold growth in several areas of the home. Subsequently, renovationactions were initiated to repair the home.
Staff from DHFS and the City of Franklin Health Department conducted a health hazard assessmentof the property for mold on July 13, 2001. Prior to July 13, this area of the state, as most ofsouthern Wisconsin, had received little, if any precipitation for approximately three weeks.
The initial walk-through of the house was conducted to determine a sampling strategy and to assessthe home for visible evidence of mold growth. The health hazard assessment of this home consistedof the following activities:
- A walk-through and visual inspection of the property.
- Collection of environmental samples for mold and bacteria, consisting of tape, wipe,and bulk samples.
- Measuring building material moisture content with a moisture meter.
- Collection of bulk samples of vermiculite (attic insulation) and floor tile for asbestos analysis.
As of the date of the walk-through, home repairs had not resumed (5). Although the walk-throughdid not reveal any demonstrative signs of water damage or mold growth, some isolated water-stainedareas and mold growth were visible. Musty, mildew odors, subjective indicators of mold growth,were not observed (6). DHFS staff determined not to use personal protective equipment (PPE) forliving areas of the home. However, PPE use was deemed appropriate in the attic, where vermiculiteinsulation, which can contain asbestos, was observed.(1)
The home had a damp basement. Dehumidifiers were not being used to control moisture. The wallswere unfinished and constructed of mortared, concrete block. There were large cracks and gaps,which can allow liquid water and water vapor from soils to seep into the basement, throughout theentire basement wall. Concrete blocks were stained, indicating seepage has occurred over a longperiod of time. This was also verified by homeowners. There is a sump with at least 18 inches ofstanding clear water, but no pump was present in the sump. Furniture, pieces of drywall, wood, andother items typically stored in basements were also present. Some mold growth was noted in thefollowing areas: the northwest corner on a floor joist; on the ceiling above the pressure tank; onpieces of drywall by the northeast wall; and on a cabinet/dresser stored in the basement. Sampleswere collected from various surfaces. The first and second floors of the home did not have visiblemold growth. Only a few areas on the first and second floors had water stains. Those areas were inthe first floor living room and in the mud room by the back entrance.
DHFS staff collected 27 environmental mold and two asbestos samples at locations throughout thehouse (6). Several of the samples were collected from areas suggested by the homeowners. Theenvironmental mold samples were collected using three methods: tape, wipe, and bulk samples. Tape samples are examined microscopically for fungal morphology such as the type of sporeproduced and other taxonomic indictors used for identification. The wipe and bulk samples arecultured on the appropriate agar for 7 days. The number of CFUs (colony forming units) producedfrom the culture can be reported based on per gram or area (square centimeter (cm2), square inch(in2), or square foot (ft2)). The Wisconsin State Laboratory of Hygiene, Occupational HealthLaboratory, Mycology Section, analyzed all mold and bacteria samples (8). The results are summarized in Table 1.
|Sample ID Number and Location||Fungi Species and Levels||Bacteria Species and Levels|
|M5||Wipe from the jacuzzi pump housing.||Penicillium sp. at 900 cfu/in2. Stachybotrus chartarum was noted at 100 cfu||Bacillus sp. at 1,000 cfu|
|M6||Bulk sample. 2nd floor wall by the patio||Penicillium sp. at 3,800 cfu||Not analyzed|
|M19||Wipe of cabinets in basement||Aspergillus versicolor at 1,400 cfu||Less that the minimum detection limit of 100 cfu|
|M20||NW corner of basement, concrete block||Cladosporium sp. at 2,600 cfu||Staphlococcus sp. at 2,400 cfu |
Cornybacterium sp. at 2,000 cfu
|M21||NE corner of basement, sheetrock above concrete block.||Penicillium sp. at 11,000 cfu, Aspergillus versicolor at 250 cfu||Less than the minimum detection limit of 100 cfu|
|M22||NE corner of basement, sheet rock leaning against wall||Aspergillus versicolor at 50 cfu, |
Stachybotrus chartarum at 17 cfu.
|Less than the minimum detection limit of 100 cfu|
While conducting the assessment, DHFS staff determined that some of the materials noted in thehouse could contain asbestos. As a result, two samples were collected for laboratory analysis - onebulk sample of attic insulation (possibly vermiculite) and one from a nine by nine foot area of floortile from an upstairs bedroom. The Wisconsin State Laboratory of Hygiene also analyzed theasbestos samples (7). During the assessment, a direct readout meter was used to determine themoisture content of building materials. Of the eight measurements taken, none exceeded 15%moisture content. Typically, a moisture reading of 17% or less is considered acceptable (6).
Presently, no nationally recognized standards have been established to compare environmental airconcentrations of most materials of biological origin, including fungi. Several guidance documentsare available on the assessment, control, remediation, and prevention of indoor biologicalcontamination. The documents include: (1) the U.S. Environmental Protection Agency's "MoldRemediation in Schools and Commercial Buildings"; (2) state guidelines from California,Minnesota, and New York; and, (3) the Institute of Inspection Cleaning and RestorationCertification's (IICRC) Standard and Reference Guide for Professional Water Damage Restoration. Many health agencies, including DHFS, use those documents as references.
Some of the factors considered in determining exposure risk to fungi are: (1) the species of fungipresent in the environment; (2) the levels of each species identified in environmental sample(s); (3)whether an environmental pathway(s), such as contaminated air, exists; (4) whether human exposurepathways, such as inhalation or ingestion, occur; (5) whether a susceptible population or individualis present; and, (6) whether the person receives a sufficient dose to cause an adverse health effect. The most common type of human response to environmental mold is allergic.
Table 1 indicates the presence of low to moderate fungal growth in some areas of the house. Stachybotrus chartarum, a mold that has received much attention over the last several years, wasidentified in two of the samples (8). S. chartarun has been implicated in a condition in infantscalled hemosiderosis, hemorrhaging of lung tissue. However, after reviewing the "ClevelandStudy," on which those findings were based and widely publicized, the Centers for Disease Controland Prevention released a statement stating that the association between Stachybotrus sp. andHemosiderosis sp. was not proven. The controversy surrounding the role of environmental moldand adverse health effects continues. As the scientific knowledge of molds, mycotoxins, and theirimpact on human health builds, so will the capacity to complete environmental tests and determinethe risk posed to occupants of contaminated buildings.
The levels of bacteria found were not significant (8). Humans and animals commonly shed many ofthe bacteria noted. Some of the Bacillus sp. serve as indicators of moisture or water damage but arenot uncommon in environmental samples. In some institutions, such as hospitals, culturing of theinanimate environment is done to determine if the level of sanitation and cleanliness is adequate. The bacterial levels reported in this house are low and most likely are a normal part of the bacterialload.
The following areas have been identified as being potential sources of environmental mold andshould be addressed:
- M5 - Disinfect the under part of the "jacuzzi" tub and check for leaks. This includes the motor housing, plumbing, and floor. Debris and dust were noted. The area should be HEPA vacuumed and wiped with a bleach solution or other approved bactericidal product.
- M6 - The insulation from within the exterior living room wall may indicate past waterintrusion occurred. This area needs to be further evaluated by an individual familiar with building construction to assess possible causes of the water damage. The area referred is enclosed behind the interior wall, thereby presenting a minimal exposure risk.
- M19 - This cabinet, located in the basement, should either be discarded or appropriately cleaned and refinished in a well-ventilated area.
- M20 - This and other concrete blocks may be difficult to keep free of mold. The basement is a high-moisture area and will continue to support mold growth without some corrective action. Structural work is necessary to repair the crack around the basement's perimeter. Ongoing preventive maintenance, such as using dehumidifiers and a sump pump with sump cover, would help in reducing the moisture level.
- M21 - The sheetrock in the basement's northeast corner needs to be cleaned or removed. This material is difficult to disinfect and keep clean, in particular if high moisture levels are present.
- M22 - The sheetrock leaning against the northeast basement wall should be discarded.
Typical mold problems on walls and windows can be addressed by disinfecting those areas with ahousehold bleach (chlorine) solution. Residents can prepare this solution by adding 4-6 ounces ofbleach to 1 gallon of water and applying the solution to the affected areas. Water-resistant glovesare recommended because bleach (actually the chlorine in bleach) is very reactive. Also, bleachmay discolor the areas where applied. Several applications may be needed before mold is destroyed. In some instances, the bleach solution can be placed in a spray bottle and applied by spraying. Respiratory protection should always be considered when working with chemicals in an enclosedarea. Chlorine, like other chemicals can be an irritant and can create toxic fumes when mixed with other chemicals.
This case involves indoor air quality in a residential setting. Three children, aged 9, 12, and 13, livein the household. The parents report that all the children have symptoms related to exposure toindoor air contaminants. This has not been adequately substantiated by medical examinations. Thechildren are scheduled for evaluation by a physician specializing in allergies to determine whether past mold exposures represents an issue of potential concern.
Most of the Franklin home is safe for living, but visible mold was noted in the basement and couldbe a public health hazard if not addressed. Visual inspections at other locations in the Franklinhome did not reveal any remarkable areas of visible mold growth. Tests revealed the presence oflow to moderate levels of mold growth in some areas of the house. If these areas are appropriatelyremediated and the overall water intrusions issues corrected, the entire home should be safe for reoccupancy.
Moisture readings taken of building materials did not indicate the presence of moisture levels thatpose problems or that might promote significant mold growth. Residents can safely disinfect wallsand windows with a household bleach solution, which will kill mold and prevent regrowth.
The attic insulation contains tremolite asbestos and can present an inhalation exposure risk ifdisturbed. If left undisturbed, the asbestos does not pose a public health hazard. If remolding orcleaning the home requires disturbing the insulation, professional assistance should be sought.
DHFS will continue to work the residents and the City of Franklin Health Department to address health questions and health complaints related to the indoor air quality of this household.
- Strass-Maguire & Associates, Inc., Damage Inspection, Property at 3229 W. Franklin Terrace, Franklin, WI, completed on July 31, 2000.
- Maier Construction, Inc., Damage Inspection, W, Property at 3229 W. Franklin Terrace,Franklin, WI, completed on August 28, 2000.
- Inspection and Assessment Services, Bioaerosal Assessment Final Summary Report, ,Property at 3229 W. Franklin Terrace, Franklin, WI, completed on September 11, 2000.
- Micro Air Inc., Environmental Evaluation, Property at 3229 W. Franklin Terrace, Franklin, WI, completed on October 2, 2000.
- Maier Construction, Inc., Reinspection , Property at 3229 W. Franklin Terrace, Franklin, WI, completed on May 17, 2001.
- Wisconsin Division of Public Health, Bureau of Environmental Health, Field Notes and Sampling Logs, Property at 3229 W. Franklin Terrace, Franklin, WI, completed on July 13,2001.
- Wisconsin Occupational Health Laboratory, Analytical Results of Asbestos Samples, for the Property at 3229 W. Franklin Terrace, Franklin, WI, dated July 20, 2001.
- Wisconsin Occupational Health Laboratory, Analytical Results of Environmental FungiSamples, for the Property at 3229 W. Franklin Terrace, Franklin, WI, dated July 25, 2001.
William Otto &
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health & Family Services
This Indoor Environment Fungi Contamination public health consultation was prepared by theWisconsin Department of Health and Family Services under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health consultation was begun.
Gail D. Godfrey
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.
Chief, SPS, SSAB, DHAC, ATSDR
1. PPE use is dictated by conditions observed during walk-throughs. Typically, protective equipment is used in situations where profuse mold growth is noted and multiple samples, which disturb the mold, are taken. State staff are trained and experienced in the use of PPE. Staff use discretion, while still maintaining personal safety, when using PPE. Inappropriate or casual use of PPE can also create alarm for others present.