Prepared wi th the ass is tance o f the USEPA Indoor Envi ronment Nat ional

Laboratoryand

Lei f A lber tson – UAF Fa i rbanks

An Introduction to Mold

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Topics

I. OverviewII. IndicatorsIII. Health EffectsIV. InvestigationV. Remediation VI. Prevention

I. Overview

Key information• Types of molds• Factors contributing to

mold growth

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Types of Molds

What are molds?Part of class of

“biological”

contaminants that

includes bacteria,

mildew, viruses, animal

dander, dust mites,

cockroaches, pollens

Part of “Fungi” kingdom

that includes molds,

yeasts, mushrooms, rusts

Microscopic organisms

that form and colonize

through airborne spores

Under a microscope

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Types of Molds (continued)

Over 100,000 different types; about 10 different species common indoors

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Factors Contributing to Mold Growth

What do molds need to grow?1. Food supply

2. Warm temperatures, and…

3. Moisture

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Factors Contributing to Mold Growth (cont.)

#1 - Food Sources Organic sources

Soils, food, plant matter

Human and animal hair and dander

Clothing and fabric fibers

Fibers from floor coverings, insulation, building materials

Building materials

Certain materials –particleboard, LP siding, OSB, expanded

styrene, cellulose insulation – all better food sources, absorb

and hold moisture

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Factors Contributing to Mold Growth (cont.)

#2 - Heat sources Higher indoor temperatures common from

unregulated sources – woodstoves and fireplaces

Inadequate ventilation and overcrowded spaces also contribute

Warm air holds more moisture than cold air = higher temperatures in homes = higher humidity levels

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#3 – Moisture and vapor sources Moisture sources

Building envelope leaks

Plumbing leaks

Factors Contributing to Mold Growth (cont.)

(dishwashers, toilets, plumbing fittings, washing machines, water heaters)

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Optimum Relative Humidity

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Factors Contributing to Mold Growth (cont.)

Water vapor sources Moisture often results not from water intrusion

but from high relative humidity (RH) in home Damp soil & basements (vapor flows from high

RH to low RH) Occupant activities (breathing, showering,

cooking, dishwashing, laundry, plants…average of 2.91 gal/day (Tsongas, 1999)

Condensation happens in cold spots

Source Health and Energy Testing Services, NE http//www.healthandenergy.com/

II. Indicators

Key information• Recognizing indicators of

potential mold infestation• Finding sources of information

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Recognizing Indicators

1. Known or suspected water damageOccupants may know of leak, flood,

water intrusion (helpful to know extent, length, actions taken)

Visible signs of water damage – may be clearly evident

Less visible signs require further visual investigation behind wallpaper, baseboards, cabinets; in crawlspaces, on building exteriors, rust, drywall staining

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Recognizing Indicators

2. Reports from maintenance or custodial staffKnow building history, repairs, structural

issuesMay be first to report occupant complaints

3. Musty/mildew odorsIndicator of bacterial growth; may not be

visible

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Recognizing Indicators

4. Visible moldAppearance of spores not only indicatorRange of colors (all “black” molds are not toxic,

though proceed with caution)

Growth patterns vary, depending on point of moisture contact

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II. Indicators

5. Reported health problems

Clear links allergy/respiratory

Possible flu-like symptoms, repeated viral

infections, fatigue, frequent ER

visits/hospitalizations

III. Health Impacts

Key information• Types of impacts• Who is at most at risk

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Health Impacts

“Exposure to damp and moldy environments may cause a variety of health effects, or none at all.”

www.CDC.gov/mold

Health impacts vary widely and are individual in impact.

Health issues can result from a variety of environmental issues and it can be difficult to identify specific causes.

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Types of Effects

1. IrritantExposure can irritate eyes, skin, nose, throat, and

lungs, in allergic and non-allergic individualsEffect is dose-related, usually transient

2. AllergenCommon symptoms runny nose, itchy eyes, sneezing,

sore throat, nasal congestion, eczema, dermatitisIn high concentrations, molds can trigger symptoms in

individuals with no known allergiesLong-term exposure can sensitize an individual,

inducing allergies and airway-reactivity

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Types of Effects (cont.)

3. Infectious

Direct infection occurs when pathogens attack immune-compromised individuals

E.g., Aspergillus fumigatus known to cause aspergillosis (ABPA)

4. Toxic (rare)

Toxic molds produce chemicals called mycotoxins

Certain species (e.g, stachybotrus, fusarium, trichoderma) are known carcinogens

Mycotoxins readily absorbed by intestinal lining, airways, skin

Presence of toxic molds usually associated with long-standing water problem

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Who is most at risk?

Individuals with lower-airway diseases Asthma, chronic bronchitis

• Molds directly tied to presence, persistence and increased severity of asthma episodes

Young children (birth to age 2 – critical window)

• Allergic sensitization/genetic predisposition

• Incidence of RSV

EldersIndividuals with compromised immune systemsIndividuals with allergies (upper respiratory)

IV. Investigation

Key information• Objectives of investigation• Types of sampling

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Objectives of Investigation

1.Identify all moldy areas If occupant reports mold, search throughly (under sinks, in

cabinets, behind toilets, behind furniture; sub-floor, drywall, crawl space)

2.Identify all possible causesPlumbing or appliance leaks? High humidity? Condensation?

3.Reduce exposure to occupants in home/building

4.Develop plan for clean-up/remediation

5.Ensure that maintenance staff and occupant are informed

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Types of Samples

When is sampling necessary? If legal action is being considered or there are

serious health impacts that require specialized medical treatment.

Is species identification necessary? Identifying species of mold or airborne sampling is

not recommended for investigation or remediationMicroscope can help confirm presence of

moldNo standards for exposure levels of mold /

spores

V. Remediation

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First Things First

Mold clean-up is not effective until the source of moisture is addressed.

Mold is a moisture problem

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Mold Remediation

Less than 10 sq ft PPE (minimum)

N-95 respirator, gloves, goggles

Containment: None requiredBetween 10 sq ft and 100 sq ft

PPE limited or full (use “professional judgment”)

Respirator (N-95, half-face, full-face)

Gloves, goggles, foot covering

Disposable overalls/disposable full body clothing

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Mold Remediation Continued

Containment: Limited Polyethylene sheeting ceiling to floor

around affected area, slit entry, covering flap

Maintain area under negative pressure with HEPA filtered fan unit.

Block supply and return air vents within containment area

More than 100 sq ft Call in professionals / get training

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Safety Guidelines & Resources

To prevent exposure and assure containment, critical that maintenance staff employ safety guidelines…

IICRC S520 – Standard Guide for Professional

Mold Remediation www.iicrc.org

Building Sciences Corporation - RR-0210 Mold Remediation in

Occupied Homeswww.buildingscience.c

om

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Safety Guidelines - Occupants

Home-owner or tenant information Prevention and clean-up for small areas (cleaning

non-porous surfaces and wood with detergent; repair moisture source; dry material, etc)

Many people use bleach, which kills mold, but is not a good cleaning agent Bleach is a strong respiratory irritant

Surfactant (soap) is better

VI. Prevention

Key information• Principles for existing homes

& buildings• Principles for new

construction & renovations

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Principles for Existing Homes

Work with occupants, maintenance and custodial staff to focus on prevention practices

1. Keep it clean2. Keep it dry3. Keep it well ventilated4. Keep it well maintained

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1. CleanControl dust sources

Regular cleaning

Carpet removal where possible

Use of walk-off mats

Hepa-filter vacuuming

Reduced clutter

Shoes-off policy

Principles for Existing Homes (cont.)

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Principles for Existing Homes (cont.)

2. Dry & Ventilated Ventilation

Install & use exhaust fans vented to outdoors in kitchens and bathrooms, clothes dryers–eliminate moisture that builds up from everyday activities

Attic and crawl spaces – Keep humidity below 50% to prevent condensation on building materials

Water damage Thoroughly clean & dry water-damaged carpets and

building materials (within 24 hours, if possible) or

Consider removal or replacement

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New Construction & Renovation

New homes and buildings Water damage costs up to 3X more to fix than to properly

install, maintain moisture controls

Employ mold-resistant construction products and

practices

Ensure contractors trained in installation of key

moisture-abatement materials (specifically, vapor

barriers)

Install proper ventilation to ensure regulated

temperatures and vapor/moisture reduction

Additional Resources on Mold

Indoor Air Quality Associationwww.iaqa.org

American Industrial Hygiene Association (AIHA)www.aiha.org

U.S. Environmental Protection AgencyNew Residential Mold Guide  http//epa.gov/mold/

U.S. Environmental Protection AgencyMold Resourceshttp//www.epa.gov/iaq/pubs/moldresources.html 

Additional Resources on Mold

Mold Remediation in Schools and Commercial Buildings, March 2001http//www.epa.gov/mold/mold_remediation.html

U.S. Centers for Disease Control and PreventionMolds in the Environment http//www.cdc.gov/mold/faqs.htm

Questions and Answers on Stachybotrys chartarum and other moldshttp//www.cdc.gov/nceh/airpollution/mold/stachy.htm 

Managing Water Infiltration Into Buildingshttp//www.dehs.umn.edu/iaq/flood.html