Indoor Air Quality (IAQ)

Mold Remediation 

in Schools and 

Commercial Buildings

EPA 402-K-01-001 | September 2008 | www.epa.gov/mold
This document was prepared by the Indoor Environments Division 

(IED) of the U.S. Environmental Protection Agency. IED would like to 

thank the reviewers of this document who provided many valuable and 

insightful comments, and the contractors who provided support during the 

development of this document.

EPA would also like to thank those who provided photos: Terry Brennan 

(Photo #2, Photo #3A, Photo #4A, Photo #6, Photo #8, Photo #9); Paul 

Ellringer (Photo #4C); Stephen Vesper, Ph.D. (Photo #3B); and Chin Yang, 

Ph.D. (cover photos, Photo #4B, Photo #5, Photo #7).

Please note that this document presents recommendations on mold 

remediation. EPA does not regulate mold or mold spores in indoor air.

Cover Photos: Magnified photos of different species of mold

Acknowledgements
Mold Remediation 

in Schools and 

Commercial Buildings
 
Introduction......................................................................................1

Prevention..........................................................................................3

Investigating, Evaluating, and Remediating Moisture and Mold 

Problems.......................................................................................4

Mold Remediation – Key Steps............................................................5

Plan the Remediation Before Starting Work ..........................................6

Remediation Plan ..............................................................................6

HVAC System ....................................................................................7

Hidden Mold .....................................................................................8

Remediation......................................................................................9

Table 1: Water Damage – Cleanup and Mold Prevention.......................10

Table 2: Mold Remediation Guidelines...............................................12

Cleanup Methods.............................................................................16

Personal Protective Equipment (PPE) ................................................19

Containment ...................................................................................21

Equipment......................................................................................23

How Do You Know When You Have Finished 

Remediation/Cleanup?................................................................26

Checklist for Mold Remediation...................................................27

Resources List.................................................................................29

References.......................................................................................35

Appendix A – Glossary .....................................................................37

Appendix B – introduction to molds.............................................39

Molds in the Environment.................................................................39

Health Effects and Symptoms Associated with Mold Exposure..............39

Mold Toxins.....................................................................................41

Microbial Volatile Organic Compounds (mVOCs)..................................43

Glucans or Fungal Cell Wall Components ...........................................43

Spores ............................................................................................43

Appendix C – Communication With Building Occupants..............45

Mold in Schools...............................................................................45

index ..................................................................................................47

Contents
 
Concern about indoor exposure to mold has been increasing as the public 

becomes aware that exposure to mold can cause a variety of health effects 

and symptoms, including allergic reactions. This document presents 

guidelines for the remediation/cleanup of mold and moisture problems 

in schools and commercial buildings; these guidelines include measures 

designed to protect the health of building occupants and remediators. It 

has been designed primarily for building managers, custodians, and others 

who are responsible 

for commercial 

building and school 

maintenance. It should 

serve as a reference 

for potential mold and 

moisture remediators. 

Using this document, 

individuals with little 

or no experience with 

mold remediation 

should be able to 

make a reasonable 

judgment as to whether 

the situation can be 

handled in-house. 

It will help those in 

charge of maintenance 

to evaluate an inhouse remediation 

plan or a remediation 

plan submitted by an 

outside contractor.1

Contractors and other 

professionals who 

respond to mold and 

moisture situations 

in commercial buildings and schools may also want to refer to these 

guidelines.

1 If you choose to use outside contractors or professionals, make sure they have experience cleaning up 

mold, check their references, and have them follow the recommendations presented in this document, the 

guidelines of the American Conference of Government Industrial Hygienists (ACGIH) (see Resources List), 

and/or guidelines from other professional organizations.

Molds gradually destroy the things they grow on. Prevent 

damage to building materials and furnishings, save money, 

and avoid potential health risks by controlling moisture and 

eliminating mold growth.

Introduction

Photo 2: Extensive mold contamination of ceiling and walls

Mold Remediation in Schools and Commercial Buildings 1
2 Mold Remediation in Schools and Commercial Buildings

Molds can be found almost anywhere; they can grow on virtually any 

organic substance, as long as moisture and oxygen are present. There are 

molds that can grow on wood, paper, carpet, foods, and insulation. When 

excessive moisture accumulates in buildings or on building materials, 

mold growth will often occur, particularly if the moisture problem remains 

undiscovered or unaddressed. It is impossible to eliminate all mold and 

mold spores in the indoor environment. However, mold growth can be 

controlled indoors by controlling moisture indoors.

Molds reproduce by making spores that usually cannot be seen without 

magnification. Mold spores waft through the indoor and outdoor air 

continually. When mold spores land on a damp spot indoors, they may 

begin growing and digesting whatever they are growing on in order to 

survive. Molds gradually destroy the things they grow on.

Many types of molds exist. All molds have the potential to cause health 

effects. Molds can produce allergens that can trigger allergic reactions or 

even asthma attacks in people allergic to mold. Others are known to produce 

potent toxins and/or irritants. Potential health concerns are an important 

reason to prevent mold growth and to remediate/clean up any existing 

indoor mold growth. 

Since mold requires water to grow, it is important to prevent moisture 

problems in buildings. Moisture problems can have many causes, including 

uncontrolled humidity. Some moisture problems in buildings have been 

linked to changes in building construction practices during the 1970s, ’80s, 

and ’90s. Some of these changes have resulted in buildings that are tightly 

sealed, but may lack adequate ventilation, potentially leading to moisture 

buildup. Building materials, such as drywall, may not allow moisture to 

escape easily. Moisture problems may include roof leaks, landscaping 

or gutters that direct water into or under the building, and unvented 

combustion appliances. Delayed maintenance or insufficient maintenance 

are also associated with moisture problems in schools and large buildings. 

Moisture problems in portable classrooms and other temporary structures 

have frequently been associated with mold problems.
Mold Remediation in Schools and Commercial Buildings 3

When mold growth occurs in buildings, adverse health problems may be 

reported by some building occupants, particularly those with allergies or 

respiratory problems. Remediators should avoid exposing themselves and 

others to mold-laden dusts as they conduct their cleanup activities. Caution 

should be used to prevent mold and mold spores from being dispersed 

throughout the air where they can be inhaled by building occupants.

Prevention

The key to mold control is moisture control. Solve moisture problems 

before they become mold problems!

Mold Prevention Tips

•	Fix leaky plumbing and leaks in the building envelope as soon as 

possible.

•	Watch for condensation and wet spots. Fix source(s) of moisture 

problem(s) as soon as possible.

•	Prevent moisture due to condensation by increasing surface temperature 

or reducing the moisture level in air (humidity). To increase surface 

temperature, insulate or increase air circulation. To reduce the moisture 

level in air, repair leaks, increase ventilation (if outside air is cold and 

dry), or dehumidify (if outdoor air is warm and humid).

•	Keep heating, ventilation, and air conditioning (HVAC) drip pans clean, 

flowing properly, and unobstructed.

•	Vent moisture-generating appliances, such as dryers, to the outside 

where possible.

•	Maintain low indoor humidity, below 60% relative humidity (RH), ideally 

30 – 50%, if possible.

•	Perform regular building/HVAC inspections and maintenance as 

scheduled.

•	Clean and dry wet or damp spots within 48 hours.

•	Don’t let foundations stay wet. Provide drainage and slope the ground 

away from the foundation.
4 Mold Remediation in Schools and Commercial Buildings

Investigating, Evaluating, and Remediating 

Moisture and Mold Problems

Safety Tips While Investigating and Evaluating 

Mold and Moisture Problems

•	Do not touch mold or moldy items with bare hands. 

•	Do not get mold or mold spores in your eyes.

•	Do not breathe in mold or mold spores.

•	Consult Table 2 and text for Personal Protective Equipment 

(PPE) and containment guidelines.

•	Consider using PPE when disturbing mold. The minimum PPE 

is an N-95 respirator, gloves, and eye protection.

Photo 3B: Front side of wallboard 

looks fine, but the back side is 

covered with mold

Photo 3A: Mold growing in closet as a 

result of condensation from room air

Moldy Areas Encountered During an Investigation
Mold Remediation in Schools and Commercial Buildings

5

Consult health professional

as appropriate

throughout process

Select

remediation manager

Assess size of mold problem

and note type of

mold-damaged materials

Communicate with building

occupants throughout process

as appropriate to situation

Plan remediation,

adapt guidelines to

fit situation, see Tables 1 & 2

Identify source or

cause of water or

moisture problem

Select personal protective

equipment (PPE)

Select containment

equipment

Select remediation

personnel or team

Hidden mold discovered,

reevaluate plan

Check for return of

moisture and mold problem

Clean and dry

moldy materials

See Table 2

Discard moldy 

items that can’t 

be cleaned

Dry non-moldy items 

within 48 hours

See Table 1

Fix water or

moisture problem

In-house expertise Outside expertise Remediate

Mold Remediation – Key Steps
6 Mold Remediation in Schools and Commercial Buildings

Remediation Plan

Assess the size of the mold and/or moisture 

problem and the type of damaged materials 

before planning the remediation work. 

Select a remediation manager for medium 

or large jobs (or small jobs requiring more 

than one person). The remediation plan 

should include steps to fix the water or 

moisture problem, or the problem may 

reoccur. The plan should cover the use of 

appropriate Personal Protective Equipment 

(PPE) and include steps to carefully 

contain and remove moldy building 

materials to avoid spreading the mold.2

A remediation plan may vary greatly 

depending on the size and complexity 

of the job, and may require revision if 

circumstances change or new facts are 

discovered.

The remediation manager’s highest priority 

must be to protect the health and safety of 

the building occupants and remediators. 

It is also important to communicate 

with building occupants when mold 

problems are identified.3

 In some cases,

6 Mold Remediation in Schools and Commercial Buildings

Questions to Consider Before 

Remediating

•	Are there existing moisture 

problems in the building?

•	Have building materials been 

wet more than 48 hours? (See 

Table 2 and text)

•	Are there hidden sources of 

water or is the humidity too 

high (high enough to cause 

condensation)?

•	Are building occupants reporting 

musty or moldy odors?

•	Are building occupants reporting 

health problems?

•	Are building materials or 

furnishings visibly damaged?

•	Has maintenance been delayed 

or the maintenance plan been 

altered?

•	Has the building been recently 

remodeled or has building use 

changed?

•	Is consultation with medical or 

health professionals indicated?

Plan the Remediation Before Starting Work

2 Molds are known allergens and may be toxic. You may wish to use Personal Protective Equipment (PPE) 

while investigating a mold problem, as well as during remediation/cleanup situations. The minimum PPE 

includes an N-95 respirator, gloves, and eye protection.

3 See Appendix C.
Mold Remediation in Schools and Commercial Buildings 7

especially those involving large areas of contamination, the remediation 

plan may include temporary relocation of some or all of the building 

occupants. The decision to relocate occupants should consider the size 

and type of the area affected by mold growth, the type and extent of health 

effects reported by the occupants, the potential health risks that could be 

associated with debris, and the amount of disruption likely to be caused 

by remediation activities. If possible, remediation activities should be 

scheduled for off-hours when building occupants are less likely to be 

affected.

Remediators, particularly those with health-related concerns, may wish to 

check with their doctors or health care professionals before working on 

mold remediation or investigating potentially moldy areas. If you have 

any doubts or questions, you should consult a health professional before 

beginning a remediation project.

HVAC System

Do not run the HVAC system if you know or suspect that it is contaminated 

with mold. If you suspect that it may be contaminated (it is part of an 

identified moisture problem, for instance, or there is mold growth near the 

intake to the system), consult EPA’s guide Should You Have the Air Ducts 

in Your Home Cleaned?4 before taking further action (see Resources List).

Photo 4A: Contaminated fibrous 

insulation inside air handler 

cover

Photo 4B: 

Mold growth 

on air diffuser 

in ceiling

Photo 4C: 

Moldy air duct

4

Although this document has a residential focus, it is applicable to other building types.
8 Mold Remediation in Schools and Commercial Buildings

Hidden Mold

In some cases, indoor mold growth may not be obvious. It is possible 

that mold may be growing on hidden surfaces, such as the back side of 

drywall, wallpaper, or paneling, the top of ceiling tiles, the underside of 

carpets and pads, etc. Possible locations of hidden mold can include pipe 

chases and utility tunnels (with leaking or condensing pipes), walls behind 

furniture (where condensation forms), 

condensate drain pans inside air 

handling units, porous thermal or 

acoustic liners inside ductwork, or roof 

materials above ceiling tiles (due to 

roof leaks or insufficient insulation). 

Some building materials, such as 

drywall with vinyl wallpaper over it 

or wood paneling, may act as vapor 

barriers,5

 trapping moisture underneath 

their surfaces and thereby providing 

a moist environment where mold can 

grow. You may suspect hidden mold 

if a building smells moldy, but you 

cannot see the source, or if you know 

there has been water damage and 

building occupants are reporting health 

problems. Investigating hidden mold 

problems may be difficult and will require caution when the investigation 

involves disturbing potential sites of mold growth—make sure to use PPE. 

For example, removal of wallpaper can lead to a massive release of spores 

from mold growing on the underside of the paper. If you believe that you 

may have a hidden mold problem, you may want to consider hiring an 

experienced professional. If you discover hidden mold, you should revise 

your remediation plan to account for the total area affected by mold growth.

Photo 5: Mold growth behind wallpaper

5

For more information on vapor barriers and building construction, see Resources List. It is important that 

building materials be able to dry; moisture should not be trapped between two vapor barriers or mold may 

result.

Hidden Mold Growth
Mold Remediation in Schools and Commercial Buildings 9

1. Fix the water or humidity problem. Complete and carry out repair plan 

if appropriate. Revise and/or carry out maintenance plan if necessary. 

Revise remediation plan, 

as necessary, if more 

damage is discovered 

during remediation. See 

Mold Remediation – 

Key Steps (page 5) and 

Resources List (page 29) 

for additional information.

2. Continue to communicate 

with building occupants, as 

appropriate to the situation. 

Be sure to address all 

concerns.

3. Completely clean up mold 

and dry water-damaged 

areas. Select appropriate 

cleaning and drying 

methods for damaged/

contaminated materials. 

Carefully contain and 

remove moldy building 

materials. Use appropriate Personal Protective Equipment (PPE). 

Arrange for outside professional support if necessary.

The Key to Mold Control is Moisture 

Control!

•	When addressing mold problems, don’t 

forget to address the source of the moisture 

problem, or the mold problem may simply 

reappear!

•	Remember to check for high humidity and 

condensation problems as well as actual 

water leaks, maintenance issues, and HVAC 

system problems.

•	Protect the health and safety of the building 

occupants and remediators. Consult a 

health professional as needed. Use PPE and 

containment as appropriate when working 

with mold.

Remediation
10 Mold Remediation in Schools and Commercial Buildings

Table 1: Water Damage Cleanup and Mold Prevention6

Table 1 presents strategies to respond to water damage within 24 – 48 

hours. These guidelines are designed to help avoid the need for remediation 

of mold growth by taking quick action before growth starts. If mold growth 

is found on the materials listed in Table 1, refer to Table 2 for guidance 

on remediation. Depending on the size of the area involved and resources 

available, professional assistance may be needed to dry an area quickly and 

thoroughly. 

6 Please note that Tables 1 and 2 contain general guidelines. Their purpose is to provide basic information for 

remediation managers to first assess the extent of the damage and then to determine whether the remediation 

should be managed by in-house personnel or outside professionals. The remediation manager can then use 

the guidelines to help design a remediation plan or to assess a plan submitted by outside professionals.

10 Mold Remediation in Schools and Commercial Buildings
Mold Remediation in Schools and Commercial Buildings 11

Guidelines for Response to Clean Water Damage within 24 – 48 Hours to Prevent Mold Growth*

Water-Damaged Material† Actions

Books and papers * For non-valuable items, discard books and papers.

* Photocopy valuable/important items, discard originals.

* Freeze (in frost-free freezer or meat locker) or freeze-dry.

Carpet and backing – dry 

within 24 – 48 hours§

* Remove water with water extraction vacuum.

*	Reduce ambient humidity levels with dehumidifier.

* Accelerate drying process with fans.

Ceiling tiles * Discard and replace.

Cellulose insulation * Discard and replace.

Concrete or cinder block 

surfaces

* Remove water with water extraction vacuum.

*	Accelerate drying process with dehumidifiers, fans, and/or heaters.

Fiberglass insulation * Discard and replace.

Hard surface, porous 

flooring§ (Linoleum, 

ceramic tile, vinyl)

* Vacuum or damp wipe with water and mild detergent and allow to dry; scrub if 

necessary.

*	Check to make sure underflooring is dry; dry underflooring if necessary.

Non-porous, hard surfaces 

(Plastics, metals)

* Vacuum or damp wipe with water and mild detergent and allow to dry; scrub if 

necessary.

Upholstered furniture * Remove water with water extraction vacuum.

*	Accelerate drying process with dehumidifiers, fans, and/or heaters.

*	May be difficult to completely dry within 48 hours. If the piece is valuable, you

may wish to consult a restoration/water damage professional who specializes in 

furniture.

Wallboard (Drywall and 

gypsum board)

*	May be dried in place if there is no obvious swelling and the seams are intact. If

not, remove, discard, and replace.

* Ventilate the wall cavity, if possible.

Window drapes * Follow laundering or cleaning instructions recommended by the manufacturer.

Wood surfaces *	Remove moisture immediately and use dehumidifiers, gentle heat, and fans for

drying. (Use caution when applying heat to hardwood floors.)

*	Treated or finished wood surfaces may be cleaned with mild detergent and clean

water and allowed to dry.

* Wet paneling should be pried away from wall for drying.

*If mold growth has occurred or materials have been wet for more than 48 hours, consult Table 2 guidelines. Even if

materials are dried within 48 hours, mold growth may have occurred. Items may be tested by professionals if there is

doubt. Note that mold growth will not always occur after 48 hours; this is only a guideline.

These guidelines are for damage caused by clean water. If you know or suspect that the water source is contaminated

with sewage, or chemical or biological pollutants, then Personal Protective Equipment and containment are required

by the Occupational Safety and Health Administration (OSHA). An experienced professional should be consulted if you 

and/or your remediators do not have expertise remediating in contaminated water situations. Do not use fans before 

determining that the water is clean or sanitary.

† If a particular item(s) has high monetary or sentimental value, you may wish to consult a restoration/water damage

specialist.

§ The subfloor under the carpet or other flooring material must also be cleaned and dried. See the appropriate section

of this table for recommended actions depending on the composition of the subfloor.

Table 1: Water Damage – Cleanup and Mold Prevention

 11
12 Mold Remediation in Schools and Commercial Buildings

7 Please note that Tables 1 and 2 contain general guidelines. Their purpose is to provide basic information for 

remediation managers to first assess the extent of the damage and then to determine whether the remediation 

should be managed by in-house personnel or outside professionals. The remediation manager can then use 

the guidelines to help design a remediation plan or to assess a plan submitted by outside professionals.

8 Although this document has a residential focus, it is applicable to other building types.

Table 2: Mold Remediation Guidelines7

Table 2 presents remediation guidelines for building materials that have or 

are likely to have mold growth. The guidelines in Table 2 are designed to 

protect the health of occupants and cleanup personnel during remediation. 

These guidelines are based on the 

area and type of material affected 

by water damage and/or mold 

growth. Please note that these are 

guidelines; some professionals may 

prefer other cleaning methods. If 

you are considering cleaning your 

ducts as part of your remediation 

plan, you should consult EPA’s 

publication entitled, Should You 

Have the Air Ducts In Your Home 

Cleaned?8 (see Resources List). If possible, remediation activities should 

be scheduled for off-hours when building occupants are less likely to be 

affected.

Although the level of personal protection suggested in these guidelines is 

based on the total surface area contaminated and the potential for remediator 

and/or occupant exposure, professional judgment should always play a part 

in remediation decisions. These remediation guidelines are based on the size 

of the affected area to make it easier for remediators to select appropriate 

techniques, not on the basis of health effects or research showing there 

is a specific method appropriate at a certain number of square feet. The 

guidelines have been designed to help construct a remediation plan. The 

remediation manager will then use professional judgment and experience 

to adapt the guidelines to particular situations. When in doubt, caution is 

advised. Consult an experienced mold remediator for more information.

Mold and Indoor Air Regulations and 

Standards

Standards or Threshold Limit Values (TLVs) 

for airborne concentrations of mold, or mold 

spores, have not been set. As of December 

2000, there are no EPA regulations or 

standards for airborne mold contaminants.
Mold Remediation in Schools and Commercial Buildings 13

In cases in which a particularly toxic mold species has been identified or is 

suspected, when extensive hidden mold is expected (such as behind vinyl 

wallpaper or in the HVAC 

system), when the chances of 

the mold becoming airborne 

are estimated to be high, or 

sensitive individuals (e.g., 

those with severe allergies or 

asthma) are present, a more 

cautious or conservative approach to remediation is indicated. Always make 

sure to protect remediators and building occupants from exposure to mold.

Health Concerns

If building occupants are reporting serious health 

concerns, you should consult a health professional.
14

Material or Furnishing

Affected

Cleanup

Methods†

Personal Protective 

Equipment

Containment

SMALL – Total Surface Area Affected Less Than 10 square feet (ft2

)

Books and papers 3

Minimum

N-95 respirator, gloves, and 

goggles

None required Carpet and backing 1, 3

Concrete or cinder block 1, 3

Hard surface, porous flooring

(Linoleum, ceramic tile, vinyl)

1, 2, 3

Non-porous, hard surfaces 

(Plastics, metals)

1, 2, 3

Upholstered furniture & drapes 1, 3

Wallboard (Drywall and gypsum 

board)

3

Wood surfaces 1, 2, 3

MEDIUM – Total Surface Area Affected Between 10 and 100 (ft2

)

Books and papers 3

Limited or Full

Use professional judgment, 

consider potential for 

remediator exposure and size 

of contaminated area

Limited

Use professional judgment, 

consider potential for 

remediator/occupant exposure 

and size of contaminated 

area

Carpet and backing 1, 3, 4

Concrete or cinder block 1, 3

Hard surface, porous flooring

(Linoleum, ceramic tile, vinyl)

1, 2, 3

Non-porous, hard surfaces 

(Plastics, metals)

1, 2, 3

Upholstered furniture & drapes 1, 3, 4

Wallboard (Drywall and gypsum 

board)

3, 4

Wood surfaces 1, 2, 3

LARGE – Total Surface Area Affected Greater Than 100 (ft2

) or Potential for 

Increased Occupant or Remediator Exposure During Remediation Estimated to be Significant

Books and papers 3

Full

Use professional judgment, 

consider potential for 

remediator exposure and size 

of contaminated area

Full

Use professional judgment, 

consider potential for 

remediator/occupant exposure 

and size of contaminated 

area

Carpet and backing 1, 3, 4

Concrete or cinder block 1, 3

Hard surface, porous flooring

(Linoleum, ceramic tile, vinyl)

1, 2, 3, 4

Non-porous, hard surfaces 

(Plastics, metals)

1, 2, 3

Upholstered furniture & drapes 1, 3, 4

Wallboard (Drywall and gypsum 

board)

3, 4

Wood surfaces 1, 2, 3, 4

Table 2: Guidelines for Remediating Building Materials with Mold Growth 

Caused by Clean Water*
 15

Table 2 continued

*Use professional judgment to determine prudent levels of Personal Protective Equipment and containment

for each situation, particularly as the remediation site size increases and the potential for exposure 

and health effects rises. Assess the need for increased Personal Protective Equipment, if, during the

remediation, more extensive contamination is encountered than was expected. Consult Table 1 if materials 

have been wet for less than 48 hours, and mold growth is not apparent. 

These guidelines are for damage caused by clean water. If you know or suspect that the water source is

contaminated with sewage, or chemical or biological pollutants, then the Occupational Safety and Health 

Administration (OSHA) requires PPE and containment. An experienced professional should be consulted if

you and/or your remediators do not have expertise in remediating contaminated water situations.

†

Select method most appropriate to situation. Since molds gradually destroy the things they grow on, if mold 

growth is not addressed promptly, some items may be damaged such that cleaning will not restore their 

original appearance. If mold growth is heavy and items are valuable or important, you may wish to consult a

restoration/water damage/remediation expert. Please note that these are guidelines; other cleaning methods 

may be preferred by some professionals.

Cleanup Methods

Method 1: Wet vacuum (in the case of porous materials, some mold spores/fragments will remain in the 

material but will not grow if the material is completely dried). Steam cleaning may be an alternative for 

carpets and some upholstered furniture.

Method 2: Damp-wipe surfaces with plain water or with water and detergent solution (except wood—use 

wood floor cleaner); scrub as needed.

Method 3: High-efficiency particulate air (HEPA) vacuum after the material has been thoroughly dried. 

Dispose of the contents of the HEPA vacuum in well-sealed plastic bags.

Method 4: Discard – remove water-damaged materials and seal in plastic bags while inside of containment, 

if present. Dispose of as normal waste. HEPA vacuum area after it is dried.

Personal Protective Equipment (PPE)

Minimum: Gloves, N-95 respirator, goggles/eye protection

Limited: Gloves, N-95 respirator or half-face respirator with HEPA filter, disposable overalls, goggles/eye

protection

Full: Gloves, disposable full body clothing, head gear, foot coverings, full-face respirator with HEPA filter

Containment

Limited: Use polyethylene sheeting ceiling to floor around affected area with a slit entry and covering flap;

maintain area under negative pressure with HEPA-filtered fan unit. Block supply and return air vents within

containment area.

Full: Use two layers of fire-retardant polyethylene sheeting with one airlock chamber. Maintain area under

negative pressure with HEPA-filtered fan exhausted outside of building. Block supply and return air vents

within containment area.

Table developed from literature and remediation documents including Bioaerosols: Assessment and 

Control (American Conference of Governmental Industrial Hygienists, 1999) and IICRC S500, Standard 

and Reference Guide for Professional Water Damage Restoration (Institute of Inspection, Cleaning and

Restoration, 1999); see Resources List for more information.
16 Mold Remediation in Schools and Commercial Buildings

9 If you are unsure what to do, or if the item is expensive or of sentimental value, you may wish to consult a 

specialist. Specialists in furniture repair/restoration, painting, art restoration and conservation, carpet and rug 

cleaning, water damage, and fire/water restoration are commonly listed in phone books. Be sure to ask for 

and check references; look for affiliation with professional organizations. See Resources List.

Molds Can Damage Building 

Materials and Furnishings 

Mold growth can eventually cause 

structural damage to a school or 

large building, if a mold/moisture 

problem remains unaddressed 

for a long time. In the case of a 

long-term roof leak, for example, 

molds can weaken floors and

walls as the molds feed on wet 

wood. If you suspect that mold 

has damaged building integrity, 

you should consult a structural 

engineer or other professional 

with expertise in this area.

Photo 6: Heavy mold growth on underside of 

spruce floorboards

A variety of mold cleanup methods are available for remediating damage 

to building materials and furnishings caused by moisture control problems 

and mold growth. The specific method or group of methods used will 

depend on the type of material affected, as presented in Table 2. Please note 

that professional remediators may use some methods not covered in these 

guidelines; absence of a method in the guidelines does not necessarily mean 

that it is not useful.9

Method 1: Wet Vacuum

Wet vacuums are vacuum cleaners designed to collect water. They can be 

used to remove water from floors, carpets, and hard surfaces where water 

has accumulated. They should not be used to vacuum porous materials, 

Cleanup Methods
Mold Remediation in Schools and Commercial Buildings 17

such as gypsum board. They should be used only when materials 

are still wet—wet vacuums may spread spores if sufficient 

liquid is not present. The tanks, hoses, and attachments of these 

vacuums should be thoroughly cleaned and dried after use 

since mold and mold spores may stick to the surfaces.

Method 2: Damp Wipe

Whether dead or alive, mold is 

allergenic, and some molds may 

be toxic. Mold can generally be 

removed from non-porous (hard) 

surfaces by wiping or scrubbing 

with water, or water and detergent. It is important to dry these surfaces 

quickly and thoroughly to discourage further mold growth. Instructions for 

cleaning surfaces, as listed on product labels, should always be read and 

followed. Porous materials that are wet and have mold growing on them 

may have to be discarded. Since molds will infiltrate porous substances 

and grow on or fill in empty spaces or crevices, the mold can be difficult or 

impossible to remove completely.

Method 3: HEPA Vacuum

HEPA (High-Efficiency Particulate Air) vacuums are recommended for 

final cleanup of remediation areas after materials have been thoroughly 

dried and contaminated materials removed. HEPA vacuums are also 

recommended for cleanup of dust that may have settled on surfaces outside 

the remediation area. Care must be taken to ensure that the filter is properly 

seated in the vacuum so that all the air must pass through the filter. When 

changing the vacuum filter, remediators should wear PPE to prevent 

exposure to the mold that has been captured. The filter and contents of the 

HEPA vacuum must be disposed of in well-sealed plastic bags.

Mold and Paint 

Don’t paint or caulk moldy surfaces; clean and dry 

surfaces before painting. Paint applied over moldy 

surfaces is likely to peel.
18 Mold Remediation in Schools and Commercial Buildings

Method 4: Discard – Remove Damaged Materials and Seal in 

Plastic Bags

Building materials and furnishings that are contaminated with mold 

growth and are not salvageable should be double-bagged using 

6-mil polyethylene sheeting. These materials can then usually be 

discarded as ordinary construction waste. It is important to package 

mold-contaminated materials in sealed bags before removal from 

the containment area to minimize the dispersion of mold spores 

throughout the building. Large items that have heavy mold growth 

The purpose of mold remediation is to remove the mold to prevent human exposure 

and damage to building materials and furnishings. It is necessary to clean up mold 

contamination, not just to kill the mold. Dead mold is still allergenic, and some 

dead molds are potentially toxic. The use of a biocide, such as chlorine bleach, is 

not recommended as a routine practice during mold remediation, although there 

may be instances where professional judgment may indicate its use (for example, 

when immune-compromised individuals are present). In most cases, it is not 

possible or desirable to sterilize an area; a background level of mold spores will 

remain in the air (roughly equivalent to or lower than the level in outside air). These 

spores will not grow if the moisture problem in the building has been resolved.

If you choose to use disinfectants or biocides, always ventilate the area. Outdoor air 

may need to be brought in with fans. When using fans, take care not to distribute 

mold spores throughout an unaffected area. Biocides are toxic to humans, as well as 

to mold. You should also use appropriate PPE and read and follow label precautions. 

Never mix chlorine bleach solution with cleaning solutions or detergents that contain 

ammonia; toxic fumes could be produced.

Some biocides are considered pesticides, and some States require that only 

registered pesticide applicators apply these products in schools. Make sure anyone 

applying a biocide is properly licensed, if necessary. Fungicides are commonly 

applied to outdoor plants, soil, and grains as a dust or spray—examples include 

hexachlorobenzene, organomercurials, pentachlorophenol, phthalimides, and 

dithiocarbamates. Do not use fungicides developed for use outdoors for mold 

remediation or for any other indoor situation.

Mold Remediation/Cleanup and Biocides
Mold Remediation in Schools and Commercial Buildings 19

should be covered with polyethylene sheeting and sealed with duct tape 

before they are removed from the containment area.

Personal Protective Equipment (PPE)

If the remediation job disturbs mold and mold spores become airborne, 

then the risk of respiratory exposure goes up. Actions that are likely to stir 

up mold include: breakup of 

moldy porous materials such as 

wallboard; invasive procedures 

used to examine or remediate mold growth in a wall cavity; actively 

stripping or peeling wallpaper to remove it; and using fans to dry items.

The primary function of Personal Protective Equipment (PPE) is to avoid 

inhaling mold and mold spores and to avoid mold contact with the skin or 

eyes. The following sections discuss the different types of PPE that can be 

used during remediation activities. Please note that all individuals using 

certain PPE equipment, such as half-face or full-face respirators, must be 

trained, must have medical clearance, and must be fit-tested by a trained 

professional. In addition, the use of respirators must follow a complete 

respiratory protection program as specified by the Occupational Safety and 

Health Administration (OSHA) 

(see Resources List for more 

information).

Skin and Eye Protection

Gloves are required to protect 

the skin from contact with mold 

allergens (and in some cases 

mold toxins) and from potentially 

irritating cleaning solutions. Long 

gloves that extend to the middle 

of the forearm are recommended. 

The glove material should 

Always use gloves and eye protection 

when cleaning up mold!

Photo 7: Remediation worker with 

limited PPE

Personal Protective Equipment
20 Mold Remediation in Schools and Commercial Buildings

be selected based on the type of materials being handled. If you are using a 

biocide (such as chlorine bleach) or a strong cleaning solution, you should 

select gloves made from natural rubber, neoprene, nitrile, polyurethane, or 

PVC. If you are using a mild detergent or plain water, ordinary household 

rubber gloves may be used. 

To protect your eyes, use properly fitted goggles or a full-face respirator 

with HEPA filter. Goggles must be designed to prevent the entry of dust 

and small particles. Safety glasses or goggles with open vent holes are not 

acceptable.

Respiratory Protection

Respirators protect cleanup workers from inhaling airborne mold, mold 

spores, and dust.

Minimum: When cleaning up a small area affected by mold, you should 

use an N-95 respirator. This device covers the nose and mouth, will filter 

out 95% of the particulates in the air, and is available in most hardware 

stores.

Limited: Limited PPE includes use of a half-face or full-face air purifying 

respirator (APR) equipped with a HEPA filter cartridge. These respirators 

contain both inhalation and exhalation valves that filter the air and ensure 

that it is free of mold particles. Note that half-face APRs do not provide eye 

protection. In addition, the HEPA filters do not remove vapors or gases. 

You should always use respirators approved by the National Institute for 

Occupational Safety and Health (see Resources List).

Full: In situations in which high levels of airborne dust or mold spores 

are likely or when intense or long-term exposures are expected (e.g., the 

cleanup of large areas of contamination), a full-face, powered air purifying 

respirator (PAPR) is recommended. Full-face PAPRs use a blower to force 

air through a HEPA filter. The HEPA-filtered air is supplied to a mask that 

covers the entire face or a hood that covers the entire head. The positive 

pressure within the hood prevents unfiltered air from entering through 

penetrations or gaps. Individuals must be trained to use their respirators 

before they begin remediation. The use of these respirators must be in 

compliance with OSHA regulations (see Resources List).
Mold Remediation in Schools and Commercial Buildings 21

Disposable Protective Clothing

Disposable clothing is recommended during a medium or large remediation 

project to prevent the transfer and spread of mold to clothing and to 

eliminate skin contact with mold.

Limited: Disposable paper overalls can be used.

Full: Mold-impervious disposable head and foot coverings, and a body suit 

made of a breathable material, such as TYVEK®, should be used. All gaps, 

such as those around ankles and wrists, should be sealed (many remediators 

use duct tape to seal clothing).

Containment

The purpose of containment during remediation activities is to limit release 

of mold into the air and surroundings, in order to minimize the exposure 

of remediators and building 

occupants to mold. Mold and 

moldy debris should not be 

allowed to spread to areas 

in the building beyond the 

contaminated site.

The two types of containment 

recommended in Table 2 are 

limited and full. The larger 

the area of moldy material, 

the greater the possibility of 

human exposure and the greater 

the need for containment. In 

general, the size of the area 

helps determine the level of 

containment. However, a heavy 

growth of mold in a relatively small area could release more spores than 

a lighter growth of mold in a relatively large area. Choice of containment 

should be based on professional judgment.10 The primary object of 

containment should be to prevent occupant and remediator exposure to 

mold.

Containment Tips

•	Always maintain the containment area 

under negative pressure.

•	Exhaust fans to outdoors and ensure that 

adequate makeup air is provided.

•	If the containment is working, the 

polyethylene sheeting should billow 

inwards on all surfaces. If it flutters or

billows outward, containment has been 

lost, and you should find and correct the

problem before continuing your remediation 

activities.

10 For example, a remediator may decide that a small area that is extensively contaminated and has the 

potential to distribute mold to occupied areas during cleanup should have full containment, whereas a large 

wall surface that is lightly contaminated and easily cleaned would require only limited containment.
22 Mold Remediation in Schools and Commercial Buildings

Limited Containment 

Limited containment is generally recommended for areas involving between 

10 and 100 square feet (ft2) of mold contamination. The enclosure around 

the moldy area should consist of a single layer of 6-mil, fire-retardant 

polyethylene sheeting. The containment should have a slit entry and 

covering flap on the outside of the containment area. For small areas, the 

polyethylene sheeting can be affixed to floors and ceilings with duct tape. 

For larger areas, a steel or wooden stud 

frame can be erected and polyethylene 

sheeting attached to it. All supply and 

air vents, doors, chases, and risers within 

the containment area must be sealed with 

polyethylene sheeting to minimize the 

migration of contaminants to other parts of 

the building. Heavy mold growth on ceiling 

tiles may impact HVAC systems if the 

space above the ceiling is used as a return 

air plenum. In this case, containment should 

be installed from the floor to the ceiling 

deck, and the filters in the air handling units 

serving the affected area may have to be 

replaced once remediation is finished.

The containment area must be maintained 

under negative pressure relative to 

surrounding areas. This will ensure that 

contaminated air does not flow into 

adjacent areas. This can be done with a 

HEPA-filtered fan unit exhausted outside 

of the building. For small, easily contained 

areas, an exhaust fan ducted to the outdoors 

can also be used. The surfaces of all objects removed from the containment 

area should be remediated/cleaned prior to removal. The remediation 

guidelines outlined in Table 2 can be implemented when the containment is 

completely sealed and is under negative pressure relative to the surrounding 

area.

Photo 8: Full containment on large job

Containment Area
Mold Remediation in Schools and Commercial Buildings 23

Photo 9: Moisture meter 

measuring moisture content 

of plywood subfloor

Moisture Meter

Full Containment

Full containment is recommended for the cleanup of mold-contaminated 

surface areas greater than 100 ft2 or in any situation in which it appears 

likely that the occupant space would be further contaminated without 

full containment. Double layers of polyethylene should be used to create 

a barrier between the moldy area and other parts of the building. A 

decontamination chamber or airlock should be constructed for entry into 

and exit from the remediation area. The entryways to the airlock from the 

outside and from the airlock to the main containment area should consist 

of a slit entry with covering flaps on the outside surface of each slit entry. 

The chamber should be large enough to hold a waste container and allow a 

person to put on and remove PPE. All contaminated PPE, except respirators, 

should be placed in a sealed bag while in this chamber. Respirators should 

be worn until remediators are outside the decontamination chamber. PPE 

must be worn throughout the final stages of HEPA vacuuming and dampwiping of the contained area. PPE must also be worn during HEPA vacuum 

filter changes or cleanup of the HEPA vacuum.

Equipment

Moisture Meters: Measure/Monitor 

Moisture Levels in Building Materials

Moisture meters may be helpful for measuring the 

moisture content in a variety of building materials 

following water damage. They can also be used to 

monitor the process of drying damaged materials. 

These direct reading devices have a thin probe 

which can be inserted into the material to be tested 

or can be pressed directly against the surface of the 

material. Moisture meters can be used on materials 

such as carpet, wallboard, wood, brick, and concrete.
24 Mold Remediation in Schools and Commercial Buildings

Humidity Gauges or Meters: Monitor Moisture Levels in the 

Air

Humidity meters can be used to monitor humidity indoors. Inexpensive 

(<$50) models are available that monitor both temperature and humidity.

Humidistat: Turns on HVAC System at Specific Relative 

Humidity (RH)

A humidistat is a control device that can be connected to the HVAC system 

and adjusted so that, if the humidity level rises above a set point, the HVAC 

system will automatically come on.

HVAC System Filter: Filters Outdoor Air

Use high-quality filters in your HVAC system during remediation. Consult 

an engineer for the appropriate efficiency for your specific HVAC system 

and consider upgrading your filters if appropriate. Conventional HVAC 

filters are typically not effective in filtering particles the size of mold spores. 

Consider upgrading to a filter with a minimum efficiency of 50 to 60% or 

a rating of MERV 8, as determined by Test Standard 52.2 of the American 

Society of Heating, Refrigerating, and Air Conditioning Engineers. 

Remember to change filters regularly and change them following any 

remediation activities.
Mold Remediation in Schools and Commercial Buildings 25

Sampling 

Is sampling for mold needed? In most cases, if visible mold growth is present, sampling is 

unnecessary. In specific instances, such as cases where litigation is involved, the source(s)

of the mold contamination is unclear, or health concerns are a problem, you may consider 

sampling as part of your site evaluation. Surface sampling may also be useful in order to 

determine if an area has been adequately cleaned or remediated. Sampling should be done 

only after developing a sampling plan that includes a confirmable theory regarding suspected

mold sources and routes of exposure. Figure out what you think is happening and how to prove 

or disprove it before you sample!

If you do not have extensive experience and/or are in doubt about sampling, consult an 

experienced professional. This individual can help you decide if sampling for mold is useful 

and/or needed, and will be able to carry out any necessary sampling. It is important to 

remember that the results of sampling may have limited use or application. Sampling may 

help locate the source of mold contamination, identify some of the mold species present, and 

differentiate between mold and soot or dirt. Pre- and post-remediation sampling may also be 

useful in determining whether remediation efforts have been effective. After remediation, the 

types and concentrations of mold in indoor air samples should be similar to what is found in 

the local outdoor air. Since no EPA or other Federal threshold limits have been set for mold 

or mold spores, sampling cannot be used to check a building’s compliance with Federal mold 

standards.

Sampling for mold should be conducted by professionals with specific experience in

designing mold sampling protocols, sampling methods, and interpretation of results. Sample 

analysis should follow analytical methods recommended by the American Industrial Hygiene 

Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH), 

or other professional guidelines (see Resources List). Types of samples include air samples, 

surface samples, bulk samples (chunks of carpet, insulation, wallboard, etc.), and water 

samples from condensate drain pans or cooling towers.

A number of pitfalls may be encountered when inexperienced personnel conduct sampling. 

They may take an inadequate number of samples, there may be inconsistency in sampling 

protocols, the samples may become contaminated, outdoor control samples may be omitted, 

and you may incur costs for unneeded or inappropriate samples. Budget constraints will often 

be a consideration when sampling; professional advice may be necessary to determine if it is 

possible to take sufficient samples to characterize a problem on a given budget. If it is not

possible to sample properly, with a sufficient number of samples to answer the question(s)

posed, it would be preferable not to sample. Inadequate sample plans may generate 

misleading, confusing, and useless results.

Keep in mind that air sampling for mold provides information only for the moment in time in 

which the sampling occurred, much like a snapshot. Air sampling will reveal, when properly 

done, what was in the air at the moment when the sample was taken. For someone without 

experience, sampling results will be difficult to interpret. Experience in interpretation of results

is essential.
26 Mold Remediation in Schools and Commercial Buildings

How Do You Know When You Have Finished 

Remediation/Cleanup?

1. You must have completely fixed the water or moisture problem.

2. You should complete mold removal. Use professional judgment to 

determine if the cleanup is sufficient. Visible mold, mold-damaged 

materials, and moldy odors should not be present.

3. If you have sampled, the kinds and concentrations of mold and mold 

spores in the building should be similar to those found outside, once 

cleanup activities have been completed.

4. You should revisit the site(s) shortly after remediation, and it should 

show no signs of water damage or mold growth.

5. People should be able to occupy or re-occupy the space without health 

complaints or physical symptoms.

6. Ultimately, this is a judgment call; there is no easy answer.
Mold Remediation in Schools and Commercial Buildings 27

Investigate and evaluate moisture and mold problems

 Assess size of moldy area (square feet)

 Consider the possibility of hidden mold

 Clean up small mold problems and fix moisture problems before they become large 

problems

 Select remediation manager for medium or large size mold problem

 Investigate areas associated with occupant complaints 

 Identify source(s) or cause of water or moisture problem(s)

 Note type of water-damaged materials (wallboard, carpet, etc.)

 Check inside air ducts and air handling unit

 Throughout process, consult qualified professional if necessary 

or desired

Communicate with building occupants at all stages of process, as 

appropriate

 Designate contact person for questions and comments about medium or large scale 

remediation as needed

Plan remediation

 Adapt or modify remediation guidelines to fit your situation; use professional 

judgment

 Plan to dry wet, non-moldy materials within 48 hours to prevent mold growth (see 

Table 1 and text)

 Select cleanup methods for moldy items (see Table 2 and text)

 Select Personal Protection Equipment – protect remediators 

(see Table 2 and text)

 Select containment equipment – protect building occupants 

(see Table 2 and text)

 Select remediation personnel who have the experience and training needed to 

implement the remediation plan and use Personal Protection Equipment and 

containment as appropriate

Remediate moisture and mold problems

 Fix moisture problem, implement repair plan and/or 

maintenance plan

 Dry wet, non-moldy materials within 48 hours to prevent mold growth

 Clean and dry moldy materials (see Table 2 and text)

 Discard moldy porous items that can’t be cleaned 

(see Table 2 and text)

*For details, see main text of this publication. Please note that this checklist was designed to highlight key 

parts of a school or commercial building remediation and does not list all potential steps or problems.

Checklist for Mold Remediation*
28 Mold Remediation in Schools and Commercial Buildings

 
Mold Remediation in Schools and Commercial Buildings 29

U.S. Environmental Protection Agency (EPA), 

Indoor Environments Division (IED)

An Office Building Occupant’s Guide to IAQ

www.epa.gov/iaq/pubs/occupgd.html

Biological Contaminants

www.epa.gov/iaq/biologic.html 

Building Air Quality Action Plan (for Commercial Buildings)

www.epa.gov/iaq/largebldgs/pdf_files/baqactionplan.pdf

Floods / Flooding 

www.epa.gov/iaq/flood

Indoor Air Quality (IAQ) Home Page

www.epa.gov/iaq/index.html

IAQ in Large Buildings / Commercial Buildings

www.epa.gov/iaq/largebldgs

IAQ in Schools

www.epa.gov/iaq/schools

Mold Remediation in Schools and Commercial Buildings

www.epa.gov/mold/mold_remediation.html

Mold Resources

www.epa.gov/mold/moldresources.html

Resources List – EPA
30 Mold Remediation in Schools and Commercial Buildings

The following list of resources includes information created and maintained 

by other public and private organizations. The U.S. EPA does not control 

or guarantee the accuracy, relevance, timeliness, or completeness of this 

outside information. Further, the inclusion of such resources is not intended 

to endorse any views expressed or products or services offered by the author 

of the reference or the organization operating the service on which the 

reference is maintained.

American College of Occupational and Environmental Medicine (ACOEM)

(847) 818-1800 www.acoem.org/

Referrals to physicians who have experience with environmental exposures

American Conference of Governmental Industrial Hygienists, Inc. (ACGIH)

(513) 742-2020 www.acgih.org

Occupational and environmental health and safety information

American Industrial Hygiene Association (AIHA)

(703) 849-8888 www.aiha.org

Information on industrial hygiene and indoor air quality issues including mold hazards 

and legal issues

American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. 

(ASHRAE)

(800) 527-4723 www.ashrae.org

Information on engineering issues and indoor air quality

Association of Occupational and Environmental Clinics (AOEC)

(888) 347-AOEC (2632) www.aoec.org

Referrals to clinics with physicians who have experience with environmental exposures, 

including exposures to mold; maintains a database of occupational and environmental 

cases

Resources List – OTHER
Mold Remediation in Schools and Commercial Buildings 31

Asthma and Allergic Diseases:

American Academy of Allergy, Asthma & Immunology (AAAAI)

(414) 272-6071 www.aaaai.org

Physician referral directory, information on allergies and asthma

Asthma and Allergy Foundation of America (AAFA)

(800) 7-ASTHMA (800-727-8462) www.aafa.org

Information on allergies and asthma

American Lung Association (ALA)

(800) LUNGUSA (800-586-4872) www.lungusa.org

Information on allergies and asthma

Asthma and Allergy Network/Mothers of Asthmatics, Inc. (AAN-MA)

(800) 878-4403 or (703) 641-9595 www.aanma.org

Information on allergies and asthma

National Institute of Allergy and Infectious Diseases (NIAID)

(301) 496-5717 www.niaid.nih.gov/

Information on allergies and asthma

National Jewish Medical and Research Center

(800) 222-LUNG (800-222-5864) www.nationaljewish.org/

Information on allergies and asthma

Canada Mortgage and Housing Corporation (CMHC)

(613) 748-2000 [International] www.cmhc-schl.gc.ca/

Several documents on mold-related topics available

Carpet and Rug Institute (CRI)

(706) 278-3176 www.carpet-rug.org/

Carpet maintenance, restoration guidelines for water-damaged carpet, other carpetrelated issues

Centers for Disease Control and Prevention (CDC)

(800) CDC-INFO (232-4636) www.cdc.gov

Information on health-related topics including asthma, molds in the environment, and 

occupational health

CDC’s National Center for Environmental Health (NCEH)

(800) CDC-INFO (232-4636) www.cdc.gov/mold/stachy.htm

Questions and answers on Stachybotrys chartarum and other molds
32 Mold Remediation in Schools and Commercial Buildings

Energy and Environmental Building Association

(952) 881-1098 www.eeba.org 

Information on energy-efficient and environmentally responsible buildings, humidity/

moisture control/vapor barriers

Floods/ Flooding:

Federal Emergency Management Agency (FEMA)

(800) 621-FEMA (3362) www.fema.gov/hazard/flood/index.shtm

Publications on floods, flood proofing, etc.

University of Minnesota, Department of Environmental Health & Safety

(612) 626-6002 www.dehs.umn.edu/

Managing water infiltration into buildings

University of Wisconsin-Extension, The Disaster Handbook

(608) 262-3980 www.uwex.edu/ces/news/handbook.html

Information on floods and other natural disasters

Health Canada, Health Protection Branch, Laboratory Centre for Disease Control, Office 

of Biosafety

(613) 957-1779 www.phac-aspc.gc.ca/msds-ftss

Material Safety Data Sheets with health and safety information on infectious 

microorganisms, including Aspergillus and other molds and airborne biologicals

Indoor Environmental Remediation Board (IERB)

(916) 736-1100 www.ierb.org

Information on best practices in building remediation

Institute of Inspection, Cleaning and Restoration Certification (IICRC)

(360) 693-5675 www.iicrc.org

Information on and standards for the inspection, cleaning, and restoration industry

International Society of Cleaning Technicians (ISCT)

(800) WHY-ISCT (800-949-4728)

Information on cleaning such as stain removal guide for carpets

ISSA—The Worldwide Cleaning Industry Association

(800) 225-4772 www.issa.com

Education and training on cleaning and maintenance
Mold Remediation in Schools and Commercial Buildings 33

National Air Duct Cleaners Association (NADCA)

(202) 737-2926 www.nadca.com

Duct cleaning information

National Association of the Remodeling Industry (NARI)

(847) 298-9200 www.nari.org

Consumer information on remodeling, including help finding a professional remodeling 

contractor

National Institute of Building Sciences (NIBS)

(202) 289-7800 http://nibs.org

Information on building regulations, science, and technology

National Institute for Occupational Safety and Health (NIOSH)

(800) CDC-INFO (232-4636) www.cdc.gov/niosh

Health and safety information with a workplace orientation

National Pesticide Information Center (NPIC)

(800) 858-7378 http://npic.orst.edu/

Regulatory information, safety information, and product information on antimicrobials
34 Mold Remediation in Schools and Commercial Buildings

New York City Department of Health and Mental Hygiene

 www.nyc.gov/html/doh/html/epi/moldrpt1.shtml 

“Guidelines on Assessment and Remediation of Fungi in Indoor Environments”

Occupational Safety & Health Administration (OSHA)

(800) 321-OSHA (800-321-6742) www.osha.gov

Information on worker safety, includes topics such as respirator use and safety in the 

workplace

Restoration Industry Association

(800) 272-7012 www.ascr.org/

Disaster recovery, water and fire damage, emergency tips, referrals to professionals

Sheet Metal & Air Conditioning Contractors’ National Association (SMACNA)

(703) 803-2980 www.smacna.org

Technical information on topics such as air conditioning and air ducts

Smithsonian Museum Conservation Institute

(301) 238-1240 www.si.edu/mci

Guidelines for caring for and preserving furniture and wooden objects, paper-based 

materials; preservation studies

University of Michigan Herbarium

(734) 615-6200 www.herbarium.lsa.umich.edu

Specimen-based information on fungi; information on fungal ecology

University of Tulsa Indoor Air Program

(918) 631-5246 www.utulsa.edu/iaqprogram

Courses, classes, and continuing education on indoor air quality
Mold Remediation in Schools and Commercial Buildings 35

American Academy of Pediatrics, Committee on Environmental Health. “Toxic 

Effects of Indoor Air Molds.” Pediatrics. Volume 101, pp. 712-714. 1996.

American Conference of Governmental Industrial Hygienists. Bioaerosols: 

Assessment and Control. Macher, J., editor. ACGIH. Cinncinati, OH. ISBN 

1-882417-29-1. 1999.

American Conference of Governmental Industrial Hygienists. Guidelines for the 

Assessment of Bioaerosols in the Indoor Environment. ISBN 0-936712-83-X. 

1989.

American Industrial Hygiene Association. Field Guide for the Determination of 

Biological Contaminants in Environmental Samples. Dillon, H. K., Heinsohn, 

P. A., and Miller, J. D., editors. Fairfax, VA. 1996. 

American Society of Heating, Refrigerating, and Air Conditioning Engineers. 

Method of Testing General Ventilation Air-Cleaning Devices for Removal 

Efficiency by Particle Size. ASHRAE Standard 52.2. 2000.

American Society for Microbiology. Manual of Environmental Microbiology. Hurst, 

C., Editor in Chief. ASM Press. Washington, DC. 1997.

Canada Mortgage and Housing Corporation. Clean-up Procedures for Mold in 

Houses. ISBN 0-662-21133-2. 1993.

Eastern New York Occupational and Environmental Health Center. Proceedings 

of the International Conference, Saratoga Springs, NY. October 6-7, 1994.

Fungi and Bacteria in Indoor Air Environments - Health Effects, Detection, 

and Remediation. Johanning, E., and Yang, C., editors. Eastern New York 

Occupational Health Program. Latham, NY. 1995.

Eastern New York Occupational and Environmental Health Center. Bioaerosols, 

Fungi and Mycotoxins: Health Effects, Assessment, Prevention and 

Control. Johanning, E., editor. Albany, NY. 1999. (Proceedings of the Third 

International Conference on Fungi, Mycotoxins and Bioaerosols: Health 

Effects, Assessment, Prevention and Control. September 23-25, 1998.)

References
36 Mold Remediation in Schools and Commercial Buildings

Gravesen, S., Frisvad, J., and Samson, R. Microfungi. Munksgaard. Copenhagen, 

Denmark. 1994. 

“Indoor Mold and Children’s Health.” Environmental Health Perspectives, Vol. 

107, Suppl. 3, June 1999.

Institute of Inspection, Cleaning and Restoration Certification, IICRC S500,

Standard and Reference Guide for Professional Water Damage Restoration, 

2nd Edition. 1999.

Lstiburek, J. Building Science Corporation Builder’s Guide, Mixed-Humid Climates. 

Building Science Corporation and the Energy Efficient Building Association. 

1999.

National Academy of Sciences, Committee on the Assessment of Asthma and 

Indoor Air. Clearing the Air: Asthma and Indoor Air Exposures. National 

Academy Press. 2000.

National Academy of Sciences. Indoor Allergens: Assessing and Controlling 

Adverse Health Effects. National Academy Press. 1993.

National Institute for Occupational Safety and Health. Guide to the Selection and 

Use of Particulate Respirators Certified under 42 CFR 84. DHHS (NIOSH) 

Publication No. 96-101. January 1996.

New York City Department of Health, Bureau of Environmental & Occupational 

Disease Epidemiology. Guidelines on Assessment and Remediation of Fungi in 

Indoor Environments. 2000.

Occupational Safety & Health Administration. Respiratory Protection Standard, 29 

CFR 1910.134. 63 FR 1152. January 8, 1998.

U.S. Environmental Protection Agency. Should You Have the Air Ducts In Your 

Home Cleaned? EPA-402-K-97-002. October 1997.

U.S. Environmental Protection Agency. IAQ Tools for Schools. EPA-402-K-95-001. 

May 1995.

 
Mold Remediation in Schools and Commercial Buildings 37

Appendix A – Glossary

Allergen ......................Substance (such as mold) that can cause an allergic 

reaction.

APR ............................Air purifying respirator

Biocide .......................Substance or chemical that kills organisms such as 

molds.

EPA ............................Environmental Protection Agency

Fungi .........................Fungi are neither animals nor plants and are classified 

in a kingdom of their own. Fungi include molds, 

yeasts, mushrooms, and puffballs. In this document, 

the terms fungi and mold are used interchangeably. 

Molds reproduce by making spores. Mold spores 

waft through the indoor and outdoor air continually. 

When mold spores land on a damp spot indoors, 

they may begin growing and digesting whateverthey 

are growing on. Molds can grow on virtually any 

organic substance, providing moisture and oxygen 

are present. It is estimated that more than 1.5 million 

species of fungi exist.

Fungicide ....................Substance or chemical that kills fungi.

HEPA .........................High-Efficiency Particulate Air

Hypersensitivity .........Great or excessive sensitivity

IAQ ............................Indoor Air Quality

Mold ...........................Molds are a group of organisms that belong to the 

kingdom Fungi. In this document, the terms fungi and 

mold are used interchangeably. There are over 20,000 

species of mold.
38 Mold Remediation in Schools and Commercial Buildings

mVOC ........................Microbial volatile organic compound, a chemical 

made by a mold which may have a moldy or musty 

odor.

OSHA .........................Occupational Safety and Health Administration

PAPR..........................Powered air purifying respirator

PPE .............................Personal Protective Equipment

Remediate ..................Fix

Sensitization ...............Repeated or single exposure to an allergen that results 

in the exposed individual becoming hypersensitive to 

the allergen.

Spore ..........................Molds reproduce by means of spores. Spores are 

microscopic; they vary in shape and size (2 – 

100 micrometers). Spores may travel in several 

ways—they may be passively moved (by a breeze 

or waterdrop), mechanically disturbed (by a person 

or animal passing by), or actively discharged by 

the mold (usually under moist conditions or high 

humidity).
Mold Remediation in Schools and Commercial Buildings 39

Appendix B – Introduction to Molds

Molds in the Environment

Molds live in the soil, on plants, and on dead or decaying matter. Outdoors, 

molds play a key role in the breakdown of leaves, wood, and other plant 

debris. Molds belong to the kingdom Fungi, and unlike plants, they lack 

chlorophyll and must survive by digesting plant materials, using plant and 

other organic materials for food. Without molds, our environment would be 

overwhelmed with large amounts of dead plant matter.

Molds produce tiny spores to reproduce, just as some plants produce seeds. 

These mold spores can be found in both indoor and outdoor air, and settled 

on indoor and outdoor surfaces. When mold spores land on a damp spot, 

they may begin growing and digesting whatever they are growing on in 

order to survive. Since molds gradually destroy the things they grow on, 

you can prevent damage to building materials and furnishings and save 

money by eliminating mold growth.

Moisture control is the key to mold control. Molds need both food and 

water to survive; since molds can digest most things, water is the factor that 

limits mold growth. Molds will often grow in damp or wet areas indoors. 

Common sites for indoor mold growth include bathroom tile, basement 

walls, areas around windows where moisture condenses, and near leaky 

water fountains or sinks. Common sources or causes of water or moisture 

problems include roof leaks, deferred maintenance, condensation associated 

with high humidity or cold spots in the building, localized flooding due 

to plumbing failures or heavy rains, slow leaks in plumbing fixtures, 

and malfunction or poor design of humidification systems. Uncontrolled 

humidity can also be a source of moisture leading to mold growth, 

particularly in hot, humid climates.

Health Effects and Symptoms Associated with Mold Exposure

When moisture problems occur and mold growth results, building occupants 

may begin to report odors and a variety of health problems, such as 

headaches, breathing difficulties, skin irritation, allergic reactions, and 

aggravation of asthma symptoms; all of these symptoms could potentially 

be associated with mold exposure.
40 Mold Remediation in Schools and Commercial Buildings

All molds have the potential to cause health 

effects. Molds produce allergens, irritants, and 

in some cases, toxins that may cause reactions 

in humans. The types and severity of symptoms 

depend, in part, on the types of mold present, 

the extent of an individual’s exposure, the ages 

of the individuals, and their existing sensitivities 

or allergies. Specific reactions to mold growth 

can include the following:

Allergic Reactions: Inhaling or touching mold 

or mold spores may cause allergic reactions in 

sensitive individuals. Allergic reactions to mold 

are common—these reactions can be immediate 

or delayed. Allergic responses include hay 

fever-type symptoms, such as sneezing, runny 

nose, red eyes, and skin rash (dermatitis). Mold 

spores and fragments can produce allergic 

reactions in sensitive individuals regardless of 

whether the mold is dead or alive. Repeated or 

single exposure to mold or mold spores may 

cause previously non-sensitive individuals to 

become sensitive. Repeated exposure has the 

potential to increase sensitivity.

Asthma: Molds can trigger asthma attacks in 

persons who are allergic (sensitized) to molds. The irritants produced by 

molds may also worsen asthma in non-allergic (non-sensitized) people.

Hypersensitivity Pneumonitis: Hypersensitivity pneumonitis may develop 

following either short-term (acute) or long-term (chronic) exposure to 

molds. The disease resembles bacterial pneumonia and is uncommon.

Potential Health Effects 

Associated with Inhalation 

Exposure to Molds and 

Mycotoxins

•	 Allergic Reactions (e.g., 

rhinitis and dermatitis or skin 

rash)

•	 Asthma

•	 Hypersensitivity Pneumonitis

•	 Other Immunologic Effects 

Research on mold and health 

effects is ongoing. This list 

is not intended to be allinclusive.

The health effects listed above 

are well documented in humans. 

Evidence for other health effects 

in humans is less substantial and 

is primarily based on case reports 

or occupational studies.
Mold Remediation in Schools and Commercial Buildings 41

Irritant Effects: Mold exposure can cause irritation of the eyes, skin, nose, 

throat, and lungs, and sometimes can create a burning sensation in these 

areas.

Opportunistic Infections: People with weakened immune systems (i.e., 

immune-compromised or immune-suppressed individuals) may be more 

vulnerable to infections by molds (as well as more vulnerable than healthy 

persons to mold toxins). Aspergillus fumigatus, for example, has been 

known to infect the lungs of immune-compromised individuals. These 

individuals inhale the mold spores which then start growing in their lungs. 

Trichoderma has also been known to infect immune-compromised children.

Healthy individuals are usually not vulnerable to opportunistic infections 

from airborne mold exposure. However, molds can cause common skin 

diseases, such as athlete’s foot, as well as other infections such as yeast 

infections.

Mold Toxins (Mycotoxins)

Molds can produce toxic substances called mycotoxins. Some mycotoxins 

cling to the surface of mold spores; others may be found within spores. 

More than 200 mycotoxins have been identified from common molds, and 

many more remain to be identified. Some of the molds that are known to 

produce mycotoxins are commonly found in moisture-damaged buildings.

Exposure pathways for mycotoxins can include inhalation, ingestion, or 

skin contact. Although some mycotoxins are well known to affect humans 

and have been shown to be responsible for human health effects, for many 

mycotoxins, little information is available.

Aflatoxin B1 is perhaps the most well known and studied mycotoxin. It can 

be produced by the molds Aspergillus flavus and Aspergillus parasiticus and 

is one of the most potent carcinogens known. Ingestion of aflatoxin B1 can 

cause liver cancer. There is also some evidence that inhalation of aflatoxin 

B1 can cause lung cancer. Aflatoxin B1 has been found on contaminated 

grains, peanuts, and other human and animal foodstuffs. However, 

Aspergillus flavus and Aspergillus parasiticus are not commonly found on 

building materials or in indoor environments.
42 Mold Remediation in Schools and Commercial Buildings

* Information on ingestion exposure, for both humans and animals, is 

more abundant–a wide range of health effects has been reported following 

ingestion of moldy foods including liver damage, nervous system damage 

and immunological effects.

Much of the information on the human 

health effects of inhalation exposure to 

mycotoxins comes from studies done in 

the workplace and some case studies or 

case reports.* Many symptoms and human 

health effects attributed to inhalation of 

mycotoxins have been reported including: 

mucous membrane irritation, skin rash, 

nausea, immune system suppression, acute 

or chronic liver damage, acute or chronic 

central nervous system damage, endocrine 

effects, and cancer. More studies are needed 

to get a clear picture of the health effects 

related to most mycotoxins. However, it is 

clearly prudent to avoid exposure to molds 

and mycotoxins.

Some molds can produce several toxins, 

and some molds produce mycotoxins only 

under certain environmental conditions. 

The presence of mold in a building does 

not necessarily mean that mycotoxins are 

present or that they are present in large 

quantities.

Some molds, such as Aspergillus 

versicolor and Stachybotrys atra 

(chartarum), are known to produce 

potent toxins under certain 

circumstances. Although some 

mycotoxins are well known to affect 

humans and have been shown to 

be responsible for human health 

effects, for many mycotoxins, little 

information is available, and in 

some cases research is ongoing. 

For example, some strains of 

Stachybotrys atra can produce 

one or more potent toxins. In 

addition, preliminary reports from 

an investigation of an outbreak of 

pulomonary hemorrhage in infants 

suggested an association between 

pulmonary hemorrhage and exposure 

to Stachybotrys chartarum. Review 

of the evidence of this association 

at the Centers for Disease Control 

and Prevention (CDC) resulted in 

a published clarification stating

that such an association was not 

established. Research on the 

possible causes of pulumonary 

hemorrhage in infants continues. 

Consult CDC for more information 

on pulmonary hemorrhage in infants 

(see Resources List, page 31, for 

CDC contact and other information).

Toxic Molds
Mold Remediation in Schools and Commercial Buildings 43

Microbial Volatile Organic Compounds (mVOCs)

Some compounds produced by molds are volatile and are released directly 

into the air. These are known as microbial volatile organic compounds 

(mVOCs). Because these compounds often have strong and/or unpleasant 

odors, they can be the source of odors associated with molds. Exposure to 

mVOCs from molds has been linked to symptoms such as headaches, nasal 

irritation, dizziness, fatigue, and nausea. Research on mVOCs is still in the 

early phase.

Glucans or Fungal Cell Wall Components (also known as 

ß-(1,3)-D-Glucans)

Glucans are small pieces of the cell walls of molds which may cause 

inflammatory lung and airway reactions. These glucans can affect the 

immune system when inhaled. Exposure to very high levels of glucans 

or dust mixtures including glucans may cause a flu-like illness known as 

Organic Dust Toxic Syndrome (ODTS). This illness has been primarily 

noted in agricultural and manufacturing settings.

Spores

Mold spores are microscopic (2 – 10 um) and are naturally present in 

both indoor and outdoor air. Molds reproduce by means of spores. Some 

molds have spores that are easily disturbed and waft into the air and settle 

repeatedly with each disturbance. Other molds have sticky spores that will 

cling to surfaces and are dislodged by brushing against them or by other 

direct contact. Spores may remain able to grow for years after they are 

produced. In addition, whether or not the spores are alive, the allergens in 

and on them may remain allergenic for years.
44 Mold Remediation in Schools and Commercial Buildings

 
Mold Remediation in Schools and Commercial Buildings 45

Communication with building occupants is essential for successful mold 

remediation. Some occupants will naturally be concerned about mold 

growth in their building 

and the potential health 

impacts. Occupants’ 

perceptions of the health 

risk may rise if they 

perceive that information 

is being withheld from 

them. The status of the 

building investigation 

and remediation should 

be openly communicated 

including information 

on any known or 

suspected health risks.

Small remediation efforts 

will usually not require 

a formal communication 

process, but do be sure to 

take individual concerns seriously and use common sense when deciding 

whether formal communications are required. Individuals managing 

medium or large remediation efforts should make sure they understand 

and address the concerns of building occupants and communicate 

clearly what has to be done as well as possible health concerns.

Communication approaches include regular memos and/or meetings 

with occupants (with time allotted for questions and answers), 

depending on the scope of the remediation and the level of occupant 

interest. Tell the occupants about the size of the project, planned 

activities, and remediation timetable. Send or post regular updates 

on the remediation progress, and send or post a final memo when 

the project is completed or hold a final meeting. Try and resolve 

Mold in Schools

Appendix C – Communication With Building 

Occupants

Special communication strategies may be desirable 

if you are treating a mold problem in a school. 

Teachers, parents, and other locally affected groups 

should be notified of significant issues as soon

as they are identified. Consider holding a special

meeting to provide parents with an opportunity to 

learn about the problem and ask questions of school 

authorities, particularly if it is necessary/advisable to 

ensure that the school is vacated during remediation. 

For more information on investigating and 

remediating molds in schools, refer to the U.S. EPA’s 

IAQ Tools for Schools kit and the asthma companion 

piece for the IAQ Tools for Schools kit, entitled 

Managing Asthma in the School Environment.
46 Mold Remediation in Schools and Commercial Buildings

issues and occupant concerns as 

they come up. When building-wide 

communications are frequent and 

open, those managing the remediation 

can direct more time toward resolving 

the problem and less time to 

responding to occupant concerns.

If possible, remediation activities should 

be scheduled during off-hours when 

building occupants are less likely to be 

affected. Communication is important 

if occupants are relocated during 

remediation. The decision to relocate 

occupants should consider the size of 

the area affected, the extent and types of 

health effects exhibited by the occupants, 

and the potential health risks associated 

with debris and activities during the 

remediation project. When considering 

the issue of relocation, be sure to inquire 

about, accommodate, and plan for 

individuals with asthma, allergies, compromised immune systems, and other 

health-related concerns. Smooth the relocation process and give occupants 

an opportunity to participate in resolution of the problem by clearly 

explaining the disruption of the workplace and work schedules. Notify 

individuals of relocation efforts in advance, if possible.

•	Establish that the health and safety 

of building occupants are top 

priorities.

•	Demonstrate that the occupants’ 

concerns are understood and taken 

seriously.

•	Present clearly the current status 

of the investigation or remediation 

efforts.

•	Identify a person whom building 

occupants can contact directly to 

discuss questions and comments 

about the remediation activities.

Communicate, When You 

Remediate
Mold Remediation in Schools and Commercial Buildings 47

index

Biocides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Bleach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18, 20

Cleanup methods. . . . . . . . . . . . . . . . . . . . . . . 11, 14, 15, 16-19, 22, 23, 27

Containment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15, 18, 21-23, 27

Duct cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 12

Health effects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 2, 12, 39-43, 46

HEPA vacuum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15, 17, 23

Hidden mold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 8, 27

HVAC system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3, 7, 9, 22, 24

Moisture meters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 24

Mold toxins/mycotoxins. . . . . . . . . . . . . . . . . . . . . . . . 2, 13, 17, 19, 40-42

Paint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Personal Protective 

Equipment (PPE). . . . . . . . . . . . . . . 4, 6, 8, 9, 11, 14, 15, 17-21, 23, 27

Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 33

Respiratory protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15, 19, 20, 23

Sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25, 26

Schools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 29, 45

Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 25
This is a reprint of EPA document 402-K-01-001, March 2001. The guidance 

has not changed. The Resources List has been updated.

48 Mold Remediation in Schools and Commercial Buildings

NOTES
 
Indoor Air Quality (IAQ)