Evaluation of Health 

Concerns in a Public 

Middle School – 

Virginia

Elena Page, MD, MPH

Nancy Burton, PhD, MPH, CIH

Melody Kawamoto, MD, MS

R. Todd Niemeier, MS, CIH

Health Hazard Evaluation Report

HETA 2010-0045-3129

June 2011

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific 

facility evaluated and may not be universally applicable. Any recommendations made are not to be 

considered as final statements of NIOSH policy or of any agency or individual involved. Additional HHE 

reports are available at http://www.cdc.gov/niosh/hhe/
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2010-0045-3129 Page i

Report Abbreviations................................................................................................ii

Highlights of the NIOSH Health Hazard Evaluation........................iii

Summary .........................................................................................................v

Introduction ...................................................................................................1

Assessment.....................................................................................................2

Results..............................................................................................................4

Discussion.................................................................................................... 14

Conclusions................................................................................................. 18

Recommendations.................................................................................... 19

References.................................................................................................... 22

Contents

Acknowledgments

Appendix A:

Appendix B: 

Tables and Figures..................................................................................... 27

Occupational Exposure Limits and Health Effects......................... 36

Acknowledgments and Availability of Report................................ 43
Page ii Health Hazard Evaluation Report 2010-0045-3129

Abbreviations

ACGIH® American Conference of Governmental Industrial Hygienists

AIHA American Industrial Hygiene Association

ANSI American National Standards Institute

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers

CFM Cubic feet per minute

CFR Code of Federal Regulations

cm2 Square centimeter

CO Carbon monoxide

CO2 Carbon dioxide

CV Coefficient of variation

ELISA Enzyme-linked immunosorbent assay

ERMI Environmental relative moldiness index

HEPA High-efficiency particulate air

HHE Health hazard evaluation

HUD U.S. Department of Housing and Urban Development

HVAC Heating, ventilating, and air-conditioning

IEQ Indoor environmental quality

IOM Institute of Medicine

Ls-1 Liters per second

MERV Minimum efficiency reporting value

MSQPCR Mold-specific quantitative polymerase chain reaction

NAICS North American Industry Classification System

ND Not detected

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PEL Permissible exposure limit

ppm Parts per million

RH Relative humidity

μg/g Microgram per gram

U.S. EPA United States Environmental Protection Agency

VAV Variable air volume

VCS Visual contrast sensitivity

VOC Volatile organic compound

WHO World Health Organization
Health Hazard Evaluation Report 2010-0045-3129 Page iii

The National Institute for 

Occupational Safety and 

Health (NIOSH) received a 

management request for 

a health hazard evaluation 

at a middle school in 

Virginia. The request was 

submitted because some 

employees had concerns 

about exposure to mold in 

the school building.

Highlights of the

NIOSH Health

Hazard Evaluation

What NIOSH Did

● We evaluated the school in January 2010.

● We interviewed employees. We asked about their work, 

medical history, and work-related health concerns.

● We looked for signs of water damage and mold in the 

building and crawl space.

● We looked at the ventilation system design and inspected 

two of the large units to see how the units were being 

maintained.

● We checked moisture levels in the walls.

● We collected samples for mold on surfaces and in dust. 

We also collected dust samples for cat, dog, dust mite, and 

cockroach allergens.

● We measured carbon dioxide, carbon monoxide, 

temperature, and relative humidity levels.

What NIOSH Found

● Some employees had been medically evaluated by means of 

nonstandard medical tests. Their diagnoses and treatments 

were based on these tests.

● We did not link employees’ symptoms and illnesses directly 

to the conditions found in the school.

● We found that the crawl space under the renovated section 

of the school was a potential source of mold and dampness.

● The outside soil sloped toward the building, which allowed 

water to collect at the foundation and would add to the 

moisture levels in the crawl space.

● Carbon dioxide levels were elevated in some of the 

classrooms.

● Cat and dog allergens were being brought into the school. 

The levels that we found could cause health symptoms in 

allergic individuals.

● The bathrooms in the women’s locker room in the new 

gymnasium had plumbing problems.
Page iv Health Hazard Evaluation Report 2010-0045-3129

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

What Managers Can Do

● Add crawl space fans to move air from the school into the 

crawl space. Also add a moisture barrier and seal holes 

between the crawl space and school.

● Regrade the soil around the building to ensure water does 

not collect at the foundation and in the crawl space.

● Vacuum the furniture on a regular basis to remove allergens.

● Inspect the ventilation units that serve the classrooms in the 

renovated section of the building to make sure that adequate 

amounts of outdoor air are supplied to the occupied areas.

● Identify and fix water leaks in a timely matter.

● Put a no-flush policy into place for feminine hygiene 

products. This change should address the locker room 

plumbing issues.

● Create a system in which employees can report building 

concerns and provide feedback on how issues were resolved.

What Employees Can Do

● Report work-related health concerns to school officials.

● See an experienced occupational medicine physician about 

health concerns that may be related to work.

● Recognize that some symptoms may not have a medical 

diagnosis.

● Become active on the indoor environmental quality 

committee.
Health Hazard Evaluation Report 2010-0045-3129 Page v

NIOSH investigators 

evaluated a middle school 

in Virginia because 

employees had concerns 

about exposure to mold 

in the school. The main 

problem was that the 

crawl space under the 

renovated part of the 

school was a potential 

source of mold and 

dampness because of 

improper grading and 

inadequate ventilation. 

Many of the non-specific 

symptoms reported, such 

as sinus problems and 

headaches, are common 

among people working 

in offices and schools, 

as well as in the general 

population.

Summary

On January 12, 2010, NIOSH received an employer request for 

an HHE at a middle school in Virginia. The request was made 

because of staff concerns about exposure to mold in the school 

building. More than a dozen employees had reported health 

complaints they thought had been caused by mold since the school 

underwent renovation in 2006–2007. NIOSH investigators made a 

site visit on January 27–28, 2010.

We randomly selected 72 (out of 137) employees for confidential 

medical interviews; 68 were available. In addition, three employees 

on medical leave and nine employees not on our list were 

interviewed. We observed workplace conditions and the crawl 

space beneath the renovated part of the building. We reviewed 

the HVAC system balancing reports, current HVAC operations, 

and consultant reports, and we evaluated the functioning of the 

HVAC system. We measured air pressure differentials between the 

classrooms and crawl space to determine which direction air was 

flowing between the two areas. Sticky-tape samples were collected 

from surfaces for microscopic fungal analysis, and vacuum dust 

samples were collected from furniture for cat, dog, dust mite, and 

cockroach allergens. Surfaces were wiped with a Swiffer® sheet and 

analyzed for the presence of fungal species. A meter was used to 

measure the interior wall moisture levels. Measurements of CO2

, 

CO, temperature, and RH were made throughout the workday in 

the new and renovated classrooms.

Randomly selected school employees had rates of work-related 

symptoms similar to or below those reported in a study of buildings 

not known to have IEQ problems and in the general population. 

Many of the nonspecific symptoms reported, such as sinus 

problems and headaches, are common among people working in 

offices and schools, as well as in the general population. More 

serious health problems reported by some staff are not related to 

working in the building. The crawl space under the renovated part 

of the building has a dirt floor with a partial moisture barrier, 

and the soil slopes toward the foundation instead of away from 

it, allowing water to enter the crawl space. At the time of our 

site visit in January 2010, there was no visible mold growth or 

standing water in the crawl space but there was moisture under 

the partial moisture barrier. The RH levels in the crawl space were 

higher than in the school building, and there was rust on the 

crawl space metal beams. In addition, the crawl space was under 

positive pressure, which allowed air from the crawl space to enter 

the school building, because the fan that generates the negative 
Page vi Health Hazard Evaluation Report 2010-0045-3129

Keywords: NAICS 611110 (Elementary and Secondary Schools), 

mold, ERMI, crawl space, cat allergen, dog allergen, IEQ, ventilation, 

visual contrast sensitivity, chronic biotoxin-related illness

Summary

 (continued) pressure (relative to the school) was not turned on. Samples taken 

from the new part of the school had lower fungal concentrations 

overall than those from the first floor of the renovated part. 

Significant concentrations of cat allergen were found on chairs 

in several classrooms and on the couch in the teachers’ lounge. 

Recommendations to prevent water incursion and microbial 

growth are provided in this report.
Health Hazard Evaluation Report 2010-0045-3129 Page 1

Introduction

On January 12, 2010, NIOSH received an employer request for 

an HHE at a middle school in Virginia because of staff concerns 

about exposure to mold in the school building. The requestor 

noted that more than a dozen employees had reported health 

complaints since the school underwent renovation in 2006–2007. 

A site visit was made on January 27–28, 2010. An opening 

conference was held with school administrators, county health 

department personnel, industrial hygiene consultants to the school 

district, and representatives from two teacher associations.

Building Description

The school has 137 staff and over 1000 students. A building 

engineer and seven custodians service the school. An informal 

system exists for reporting building issues to the engineer, who 

either deals with them personally or refers them to the Office 

of Facilities Management. Student health services at all schools 

in the district are provided by nurses from the county health 

department. The nurse that visits the school reported that 

student inhaler use and absenteeism were lower in this school 

than in other similar schools in the district. Employees receive 

health services through their private medical providers.

The school was built in the early 1960s. The two-story building 

was built mostly of concrete block and brick; we observed 

interior dry wall in one area of the school along Bevin Drive, 

near Room 122. The crawl space is shaped as a “T” and runs 

under the Bevan Drive and Main Street hallways. The facility 

has a flat roof. The original building was extensively renovated, 

and new administrative space, library, classrooms, VAV HVAC 

systems, electrical wiring, plumbing, and communications 

systems were added. The renovation and additions were 

completed by the start of the 2007–2008 school year.

Shortly after the renovation was completed, the teacher in 

Room 116 reported musty odors. An investigation revealed a 

connection between this room (behind a built-in cabinet) and 

the dirt-floored crawl space under the renovated part of the 

building. Moisture from the crawl space had led to microbial 

growth in the cabinet. This was repaired and the opening was 

sealed. No other significant microbial growth was identified by 

the school district. The school also identified some dry traps 

in the floor drains, which were emitting odors. These drains 

are now checked on a regular basis. A water pipe leaked in the 
Page 2 Health Hazard Evaluation Report 2010-0045-3129

band room practice area in the summer of 2009; the room was 

cleaned and the carpet dried before the start of the school year.

At the time of the HHE request, several staff members had seen 

a physician who conducts medical tests for mold illness. We 

were concerned that the mold tests performed by this physician 

were not in accordance with the generally accepted standard 

of medical practice. Some teachers had been on medical leave 

at the recommendation of this physician, reportedly due to 

illness from mold exposure. The presence of mold in the 

school was inferred from the results of four ERMI tests done 

by four staff members, with test results ranging from 1.06 to 

6.93. (The ERMI scale ranges from about -10 to 20, the lowest 

to the highest. The closer the result is to 20, the greater the 

mold burden, indicating that there is likely to be significant 

water damage in that environment [Vesper et al. 2007].) The 

school district hired a consultant in 2009 to do a preliminary 

environmental assessment of the school and in 2010 to perform 

an industrial hygiene assessment of the building, focusing on 

IEQ and microbial growth.

Introduction

 (continued)

The employer provided an alphabetical list of the 137 employees, 

including teachers, custodians, cafeteria employees, administrative 

employees, counselors, and librarians. Research Randomizer 

(available at http://www.randomizer.com) was used to randomly 

generate a list of 72 employees for confidential medical interviews. 

In addition, the three employees who were on medical leave 

were contacted. Finally, an e-mail message was distributed by the 

principal’s office to all employees to let them know they could be 

interviewed if they wanted to speak with us but were not on our 

list of randomly generated names. Medical records were requested 

if employees reported seeing a physician for health issues that they 

attributed to the school environment.

We observed workplace conditions, including the conditions in 

the crawl space. We reviewed the HVAC system balancing reports, 

current HVAC operations, and consultant reports and evaluated 

the effectiveness of the HVAC system. We measured pressure 

differentials between the classrooms and crawl space with a TSI 

Model 8705 DP-CALC® micromanometer (TSI Incorporated, 

Shoreview, Minnesota). A TRAMEX Moisture Encounter meter 

Assessment
Health Hazard Evaluation Report 2010-0045-3129 Page 3

Assessment

 (continued) (Tramex Ltd., Littleton, Colorado) was used to measure the interior 

wall moisture levels. Measurements of CO2, CO, temperature, and 

RH were made throughout the work day with TSI Q-TrakTM Indoor 

Air Quality monitors (TSI Incorporated, Shoreview, Minnesota). 

The TSI Q-Trak monitors were pre- and post-calibrated at the 

NIOSH facility in Cincinnati, Ohio. Four samples were collected 

on sticky tape (SKC Inc., Eighty Four, Pennsylvania) from surfaces 

in the crawl space and gymnasium for microscopic fungal analysis. 

We also collected 10 dust samples from staff furniture to analyze 

for cat, dog, dust mite, and cockroach allergens, using a highefficiency filter sock (Midwest Filtration Company, Fairfield, Ohio) 

with a HEPA vacuum. These samples were collected in areas where 

problems were reported and in areas not known to have problems. 

The dust samples were extracted with use of a phosphate-buffered 

saline solution and analyzed with an allergen ELISA screen at an 

AIHA-accredited laboratory.

Surfaces in 24 locations were wiped with a Swiffer® sheet (Procter 

& Gamble, Cincinnati, Ohio) and analyzed for the presence of 

fungal species by a DNA-based method called MSQPCR [Haugland 

et al. 2002]. The samples were collected from the top of the door 

frame; if not enough dust was present on the door frame, as many 

surfaces as possible, such as desks and bookcases, were dusted. In 

the analytical laboratory under a biosafety hood, the Swiffer sheets 

were opened and placed on a clean sheet of aluminum foil. The 

Swiffer sheets were vacuumed for 5 minutes with a Mi test sampler 

(Indoor Biotechnologies, Charlottesville, Virginia) attached to a 

Filter Queen Magestic vacuum cleaner (Health-Mor, Strongsville, 

Ohio). The dust was sieved and 5 milligrams of dust was weighed 

out for analysis with MSQPCR. MSQPCR identifies 36 species 

of fungi commonly associated with water-damaged indoor 

environments. Established procedures were used for preparing 

conidial suspensions from dust samples, extracting DNA, and 

performing MSQPCR analyses [Haugland et al. 2002; Brinkman et 

al. 2003; Haugland et al. 2004]. All primer and probe sequences, as 

well as known species composing the assay groups, were published 

at http://www.epa.gov/microbes/moldtech.htm. The ERMI is 

determined from the results of the analysis for 26 Group 1 mold 

species associated with water damage and 10 Group 2 or common 

species not associated with water damage [Meklin et al. 2004; 

Vesper et al. 2006]. The analysis of dust samples by MSQPCR from 

a national survey of homes conducted by HUD has produced the 

ERMI for United States homes [Vesper et al. 2007].
Page 4 Health Hazard Evaluation Report 2010-0045-3129

Results

Sixty-eight employees were interviewed from the randomly 

generated list. The three employees on medical leave were 

interviewed, two over the telephone and one in person. Nine 

employees not on our list asked to be interviewed. Nineteen of the 

80 (24%) interviewed employees were male. The average length 

of employment was 7 years (range: <1–24). Employees were asked 

about any medical problems or symptoms they had, and whether 

or not they thought the symptoms were related to the school 

environment.

Of the 68 randomly selected employees, 43 reported no symptoms 

related to the school environment. The most common reported 

symptoms related to the school environment were sinus infections 

or problems, eye irritation, muscle or joint aching or swelling, 

headaches, fatigue, and cough (Figure 1). Symptoms reported by 

less than five people included nasal symptoms such as runny or 

stuffy nose or irritation, sore or dry throat, memory problems, 

frequent upper respiratory infections, skin problems, dizziness, 

and shortness of breath. One employee reported being diagnosed 

with asthma in the past school year and that asthma symptoms 

were worse on days at work. Other medical issues reported by one 

employee each included peeling fingernails, change in hair texture, 

vitamin D deficiency, vocal cord nodules, Meniere’s disease, racing 

heart, recurrent urinary frequency and urgency, tingling in various 

body parts, detached retina, and night sweats with fever and chills.

Figure 1. Symptoms Reported by Randomly Selected Employees (n=68).
Health Hazard Evaluation Report 2010-0045-3129 Page 5

Results

 (continued) Several employees reported that the physician who learned of the 

situation at the school after evaluating a few of the employees 

had set up a “clinic” to do an assessment of the middle school 

employees who wished to be evaluated by him. Most reported 

hearing about this clinic from their co-workers. The employees who 

participated in this private clinic were asked if they experienced 

a long list of symptoms, including fatigue, weakness, headache, 

red eyes, tearing, sinus, cough, diarrhea, joint pain, memory 

problems, mood swings, appetite change, metallic tastes, and 

tremor. They had blood drawn for numerous tests* and had VCS 

testing by the physician. No medical history or physical exam or 

informed consent was obtained. Each employee later received a 

letter that contained their lab results, along with a “master list” 

of test results and symptoms for all 22 employees from the school 

that were screened, with names removed. The participants were 

not provided with an individual interpretation of their results, 

but the letter instructed the participants to determine if they are 

a “case” by comparing their results to a specified list of test results 

and symptoms that was included in the letter. The employees 

were then told to contact their personal physicians and to request 

a new-patient packet if they wanted to be seen in his office after 

consulting with their personal physician. 

In addition, several of the laboratory reports of “clinic” tests 

included the following statements:

● “This test uses a kit/reagent designated by the manufacturer 

as for research use, not for clinical use.... It has not 

been cleared or approved by the U.S. Food and Drug 

Administration. The results are not intended to be used as 

the sole means for clinical diagnosis or patient management 

decisions....”

● “[This test] is an investigational assay. Clinical application has 

not been fully defined.”

● “For research use only.”

Of the 12 employees who either requested NIOSH interviews 

or were interviewed on medical leave, 2 reported no symptoms 

related to the school environment. The most commonly reported 

*Human leukocyte antigens class 1 and 2, vasoactive intestinal polypeptide, 

melanocyte stimulating hormone, leptin, antidiuretic hormone, osmolality, 

adrenocorticotropic hormone, cortisol, dehydroepiandrosterone sulfate, 

testosterone, androstenedione, transforming growth factor beta 1, 

plasminogen activator inhibitor 1, vascular endothelial growth factor, C3a, 

C4a, immunoglobulin E, Lyme Western blot, thyroid stimulating hormone, 

anticardiolipin antibodies, tissue transglutaminase IgA, antigliadin IgG and IgA, 

ferritin, and Von Willebrand factor.
Page 6 Health Hazard Evaluation Report 2010-0045-3129

Results

 (continued) symptoms were sinus infections or problems and muscle or 

joint aching or swelling (4 people each); eye irritation, memory 

problems, nausea, and insomnia (3 each); headaches, fatigue, and 

dizziness (2 each); and nasal symptoms such as runny or stuffy 

nose or irritation, sore or dry throat, skin problems, wheezing, 

and shortness of breath (1 each). One employee had been seen 

by multiple physicians and evaluated for multiple sclerosis, lupus, 

and rheumatoid arthritis. This employee was being treated by a 

physician for “chronic neurotoxin disease.” One reported being 

diagnosed with “biotoxin mediated illness.” Another employee 

reported developing Lyme disease after a tick bite, with resulting 

joint pain and swelling. The employee felt the Lyme disease 

was exacerbated by the school environment. Another employee 

reported getting a severe headache that persisted for several 

days after a colonoscopy and felt this was related to the school 

environment. The last three employees reported being treated with 

cholestyramine, and one reported being treated with erythropoietin 

for these symptoms. 

Because the ERMI values calculated from the dust samples that 

we collected were higher in the renovated part of the school than 

in the new part, the percentage of employees reporting symptoms 

they related to the school environment was calculated according to 

building location. Fifty percent (20/40) of employees interviewed 

whose primary location was the first floor of the renovated part 

reported symptoms, as did 48% (13/27) of employees whose 

primary location was in the new part, 20% (1/5) of employees who 

worked on the second floor of the renovated part, and 29% (2/7) 

who worked throughout the building.

Medical records were reviewed for seven employees, two of 

whom had seen more than one physician. Medical records for 

15 employees who reported having seen the physician who 

had conducted the “clinic” were repeatedly requested from the 

physician, but these were never received. Records were reviewed 

for an employee who had recently been diagnosed with asthma. It 

appeared that the diagnosis was based upon spirometry that did 

not meet acceptability and reproducibility criteria set forth by the 

American Thoracic Society. Also, the pattern on spirometry was 

predominantly restrictive, which is not an indication of airway 

obstruction (the pattern seen in asthma). None of the other records 

documented a work-related medical problem.
Health Hazard Evaluation Report 2010-0045-3129 Page 7

Results

 (continued) Environmental Assessment 

HVAC Systems

The VAV HVAC system has five zones served by separate airhandling units (Zones A–E), with perimeter heating units in 

the entrances. We inspected two rooftop air-handling units (E1 

and A2). These units were clean, the drain pans were dry, and 

the pleated filters fit well. The pleated filters (Purolator Defiant 

Mack 80-DTM) were classified as MERV 8 (which meets the ANSI/

ASHRAE recommendation of MERV 6 or higher) and are changed 

quarterly. The balance reports showed that all of the HVAC 

units had been tested before the reopening of the school after 

renovation. There was no information concerning balancing after 

reoccupancy.

The occupied mode was from 6:30 a.m. to 11:30 p.m., which 

provided heating or cooling depending upon the season when 

the thermostat setting was reached. The occupied set point 

temperatures ranged from 69°F to 74°F. The regular classroom 

VAV HVAC units were on a partial recirculating system that used 

a common open ceiling plenum and, according to management, 

provided a minimum of 20% outdoor air. The science classrooms 

had dedicated single-pass HVAC systems. An ozone-generating 

air cleaner was observed in Room 122. Ozone generators have 

been identified as a source of health problems in the indoor 

environment [U.S. EPA 2010], and a current policy at the school 

prohibits their use.

Indoor Environmental Quality Parameters

In January 2010, IEQ parameters (CO2, CO, temperature, 

and RH) were continually measured in 5 classrooms with VAV 

HVAC systems over a 23-hour period (Table 1). Figures A1–A5 in 

Appendix A show the IEQ parameter data in graphic form. The 

classrooms were occupied during the day. Rooms 102, 116, 122, 

and 136 were in the renovated part of the school, and Room 202 

was in the new part of the school. Spot checks for IEQ parameters 

were also made outdoors for comparison and in the crawl space 

(Table 1). We found CO2 concentrations in the four classrooms 

in the renovated part of the building ranged up to 2648 ppm, 

which exceeded recommended ANSI/ASHRAE guidelines [ANSI/

ASHRAE 2010a]. The windows in Room 136 were open during 

the sampling period, and low levels of CO (range: 0 ppm to 0.8 

ppm) were detected; these were below levels measured outside. 
Page 8 Health Hazard Evaluation Report 2010-0045-3129

Results

 (continued) Nearby automobile traffic is the likely source of the CO detected. The 

temperatures and RH levels in the classrooms were within expected 

ranges for the heating season [ANSI/ASHRAE 2010b]. Spot check 

measurements in the crawl space showed that the RH levels were higher 

in the crawl space than in the occupied area. Additional information 

concerning the ANSI/ASHRAE guidelines can be found in Appendix B.

Observations and Airflow Measurements

In the main gymnasium, there was an accumulation of material along 

the seams of the sound panels. The sticky-tape samples showed that it 

was mostly dust with a few mold spores (Table 2). It was reported to us 

that school district facility employees removed the sound panels and 

found open expansion joints in the exterior walls. These were caulked 

and the sound panels were cleaned and reinstalled after our site visit.

We found three small isolated areas of visible mold growth during our 

evaluation. Two were cardboard boxes (one in the crawl space next to 

the boiler room [Figure 2] and one in the laundry room drain) and 

one was on a wall next to a leaking pipe in the teachers’ lounge, next 

to Room 122. Dr. Vesper, from U.S. EPA, analyzed a tape sample from 

the laundry room box and identified the main fungi as Stachybotrys

spp. Stachybotrys is found in soil and prefers to grow on decaying plant 

material, cellulose, and wallboard under wet conditions. Tape samples 

from the cardboard box in the crawl space showed the presence of 

Acremonium and Dicyma organisms (Table 2). Both Acremonium and 

Dicyma require wet conditions to grow. Acremonium is found in soil 

and Dicyma prefers to grow on dead plants, paper, and cardboard.

Table 1. Measurements of IEQ parameters (CO2, CO, temperature, and RH)

Sample Location Carbon Dioxide

Range (ppm)

Carbon Monoxide 

Range (ppm)

Temperature

Range (°F)

Relative Humidity

Range (%)

Continuous Measurements

Room 102 406–1371 0 71.6–76.1 16.4–24.8

Room 116 399–1591 0 68–73 17.9–26.5

Room 122 415–1229 0 66.6–72.3 16.1–22.6

Room 136 405–2648 0–0.8 66–77.2 14.9–33.3

Room 202 322–921 0 69.4–73.8 14.5–20.3

Spot Checks

Outdoors 458–509 0–3.1 43.7–45 24.3–26.3

Crawl Space 600–900 0 60 61–67
Health Hazard Evaluation Report 2010-0045-3129 Page 9

Results

 (continued)

Table 2. Results of microscopic analysis of sticky-tape samples

Location Genera Spores/cm2

Dust from gym acoustic panel Cladosporium

Epicoccum

Smuts, Periconia, Myxomycetes

0.21

0.21

0.21

Dust from gym acoustic panel Smuts, Periconia, Myxomycetes 0.21

Cardboard in crawl space Acremonium

Dicyma

0.21

70,000

Cardboard in crawl space Acremonium

Dicyma

140,000

74,000

Figure 2. Crawl space next to the boiler room, showing rusty pipes and 

a moldy cardboard box (on the floor) that was removed during our visit.
Page 10 Health Hazard Evaluation Report 2010-0045-3129

We entered the crawl space through Room 007N and visually 

inspected a small portion of the crawl space area. The air in 

the crawl space under the renovated part of the building was 

more humid than the outside air. The crawl space was positive 

to the room (+0.0001 to 0.0025” water) at the time of the site 

visit, which means that air was flowing into the room from the 

crawl space. The room was also positive to the hallway (+0.01” 

water), which means that air was flowing from the room into 

the hallway. The exhaust fan for the crawl space was rated at 

1215 CFM (tested March 17, 2008, at 1292 CFM). Air gaps 

around the pipes allow air to enter the building from the crawl 

space. Some areas of the crawl space have a plastic moisture 

barrier. There was no standing water in the portion of the crawl 

space that we entered. In several areas along the perimeter of 

the building and in the courtyard, the grading surrounding 

the building is sloped toward the building and could result in 

additional moisture in the crawl space and school (Figure 3). 

We checked the moisture levels in walls for the teachers’ lounge, 

adjacent to Room 122; in Storage Room 7A; and the wall across 

from Room 122 and found that all measurements were within 

acceptable ranges.

Results

 (continued)

Figure 3. Water pooling at the edge of a wall inside the courtyard.
Health Hazard Evaluation Report 2010-0045-3129 Page 11

In some areas, we found stained or wet ceiling tiles (Room 7A 

and the hallway outside of the teachers’ lounge, by Room 116) 

but no obvious signs of microbial growth on these ceiling tiles. 

Rainwater had entered the school in the hallway outside Room 

16 through one of the rooftop HVAC units the week prior to the 

site visit. The storm had come from a different direction than 

usual, and the HVAC unit was not protected by metal barriers. 

School management reported to us that, since our site visit, they 

have identified and repaired the roof leaks and barrier issues that 

resulted in the water damage.

There has been an ongoing sewage backup problem in the women’s 

locker room in the new gymnasium, which also backs up into the 

physical education teacher’s shower area. The school maintenance 

staff suspects that the low-flow toilets installed during the 

renovation cannot handle disposal of feminine hygiene products. 

They have used a plumbing snake to remove the blockages.

Allergens

The levels of cat, dog, dust mite, and cockroach allergens in 

samples collected from the chairs and couch in the classrooms, 

offices, and teachers’ lounge are listed in Table A1 in Appendix A. 

We found that six of the ten dust samples had levels in the range of 

1–8 μg/g of cat allergen (Fel d1), a range that has been associated 

with sensitization of humans [Liccardi et al. 2003]. The other four 

samples had detectable, though lower, levels of cat allergen. All 

ten samples had detectable levels of dog allergen (Can f1), nine of 

which were in the 1–2 μg/g range that has been associated with 

sensitization [AIHA 2005]. Two samples were positive for dust mite 

allergen (one each for Der f1 and Der p1), but the concentrations 

were below the 2-μg/g level associated with sensitization [AIHA 

2005]. No cockroach allergen was detected in these samples at the 

laboratory limit of detection.

Environmental Relative Moldiness Index (ERMI) 

Table 3 shows the ERMI values for each of the sampled rooms. 

The complete ERMI data for each room are found in Appendix A, 

Table A2. The ERMI tests from January 2010 showed that Rooms 

116, 120, 122, 127, 130, 131, and 136, above the crawl space, had 

higher ERMI values (1.82 to 9.65) than areas in the new part of the 

school. A wide diversity of fungal species was identified. In general, 

Rooms 210, 211, 213, and 217 on the second floor of the renovated 

part of the school had lower ERMI values (3.31 to 5.66) than those 

Results

 (continued)
Page 12 Health Hazard Evaluation Report 2010-0045-3129 

rooms above the crawl space. Classrooms 142 and 143, around the 

courtyard, had ERMI values ranging from -0.35 to 6.10. The samples 

collected in the new part of the school (Rooms 100A, 101, 102, 105, 

106, 107) had very low ERMI values (-2.38 to 3.2), and the one sample 

from the office area (002B) was -0.76. Several of these samples (Rooms 

002B, 101, 102, 105, 106 and 122) had low sample weights, indicating 

that the rooms were clean and there was little dust to collect. The two 

boiler rooms had ERMI values of 0.10 and 6.74. The storage closet in 

Room 143 had the highest value (18.63). Management reported that 

this room was not cleaned after a moldy cloth had been removed in the 

fall of 2009 and the exhaust fan was not working. The room has since 

been cleaned and the fan repaired.

Table 3. Summary of ERMI values

Room Number ERMI

002B* -0.76

100A 3.2

101* -2.38

102* -1.97

105* -1.73

106* 2.86

107 -0.76

116NS 9.65

120 1.82

122* 2.57

122NS 6.08

127NS 6.02

130NS 9.27

Boiler 6.74

Boiler 6.10

131NS 9.07

136 0.78

142 -1.35

143 6.10

143NS 18.63

210NS 5.66

211NS 6.44

213NS 3.31

217NS 3.72

*low sample weight

NS – nonstandard – dust collected around room

Results

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 13

Consultant Reports

We reviewed the following information: a March 2010 report 

from a consulting company hired by the school district, and 

a series of expert witness letter reports provided by a private 

attorney to the school district, dated September 2010. These 

reports are summarized below.

The consulting company conducted several evaluations at 

the school from November 2009 until February 2010. The 

consulting company evaluated moisture content in the 

school, using infrared thermal imaging, and conducted visual 

inspections throughout the school building, crawl space, HVAC 

units, and VAV boxes for the areas over Bevan Drive. They 

found the building and HVAC units to be well-maintained. 

They did find grading issues outside near Room 07B, which 

resulted in excess moisture in that area. They did not find any 

visible mold growth in the building, but they identified at least 

40 stained ceiling tiles during their inspections. They reported 

that the ductwork for Room 116 had a higher particulate load 

than the other inspected ductwork, but they did not find visible 

mold growth in the ductwork or VAV boxes. Standing water was 

observed in the crawl space in December 2009. The consulting 

company also found that the crawl space was under either 

neutral or positive pressure with respect to the school building. 

They conducted a formal survey of the school staff to determine 

IEQ issues and investigated the reported issues, mostly related 

to odors. Air, surface-wipe, and sticky-tape samples were 

collected for mold analysis, and a limited number of air samples 

were collected for bacterial analysis. The concentrations of mold 

were lower inside than outside for culturable and spore trap 

samples. The genera of detected mold indoors were similar to 

those in outdoor samples. They noted that snow cover outside 

likely kept outside mold concentrations low. The wipe sample 

from the acoustic panels in the gymnasium did not show 

mold growth. The air samples taken from the crawl space and 

analyzed for Actinomycetes (bacteria) showed no growth.

In June 2010, expert witnesses hired by an attorney evaluated 

the construction and building design and the HVAC systems 

and collected air, dust, and sticky-tape samples for mold, 

focusing on “complaint” areas. They reported a wide range of 

issues with ventilation in the crawl space; high humidity levels; 

unsealed penetrations from the crawl space and roof; visible 

mold contamination on tar paper and pipe insulation in the 

Results

 (continued)
Page 14 Health Hazard Evaluation Report 2010-0045-3129

crawl space; missing roof flashing, leading to leakage in the 

building; lack of HVAC system balancing and proper operation; 

mold growth, plant material, and pollen grains on the VAV boxes 

and air ducts for Rooms 115, 116, and 122; and the presence of 

mold spores associated with damp environments (Chaetomium

and Stachybotrys) in air and dust samples collected in the crawl 

space, Room 116, Room 120, Room 007B, and the library.

Results

 (continued)

Discussion

Many buildings have episodes of water or moisture incursion. Mold 

comprises 25% of the biomass of the earth; therefore, mold will 

always be present in the soil. The key to preventing mold growth is 

to identify the source of moisture and to eliminate it. Although the 

ERMI was developed to evaluate homes rather than to determine 

whether or not a school or commercial building has evidence of 

fungal contamination, we can compare the ERMI results from one 

part of the building to another. Samples taken from the new part 

of the school had lower ERMI values overall than those from the 

first floor of the renovated part. The prevalence of symptoms or 

illness related to the school environment by employees, however, 

did not differ by area. The crawl space under the renovated part of 

the building has a dirt floor with a partial moisture barrier, and the 

soil ouside the building sloped toward the foundation instead of 

away from it, allowing water to enter the crawl space.

At the time of our visit in January 2010, there was no visible mold 

growth or standing water in the crawl space but there was moisture 

under the partial moisture barrier. The RH readings in the crawl 

space were higher than in the school building, and there was rust 

on the crawl space metal beams. In addition, the crawl space was 

under positive pressure because the fan that generates negative 

pressure relative to the school was not turned on. There are also 

pipe perforations through the floor, which allow air movement 

between the crawl space and the renovated part of the school. 

The most likely explanation for the higher ERMI values in the 

renovated part of the school is moisture incursion from the crawl 

space. In addition, some rooms with VAV HVAC units had high 

CO2 concentrations, which may indicate insufficient introduction 

of outdoor air.

We found significant concentrations of cat allergen on the chairs 

in several classrooms and the couch in the teachers’ lounge. 

Allergies to cat and dog dander, dust mites, and cockroaches 
Health Hazard Evaluation Report 2010-0045-3129 Page 15

have been linked to asthma exacerbation [IOM 2000; Macher et 

al. 2005]. Upholstered furniture that is not frequently cleaned is 

a significant allergen reservoir [Tranter et al. 2009]. A detailed 

discussion of IEQ issues, including mold, is in Appendix B.

Our environmental findings suggest that mold incursion is 

occurring through connections between the crawl space and the 

occupied space in the renovated part of the building, but the 

patterns and rates of symptoms do not suggest a relationship to the 

school environment. In our medical interviews, randomly selected 

employees reported common symptoms similar to those reported 

in a large study of buildings without IEQ complaints and in the 

general population.

There was heightened awareness of the suspected mold problem 

in the school; employees reported being urged to get tested at the 

private physician’s “clinic” that was set up specifically for school 

employees. Such heightened awareness might lead individuals to 

notice symptoms they might otherwise overlook and to attribute 

them to the work environment. Care must be taken when 

attributing common symptoms to particular exposures, because 

the association is as likely to be coincidental as to be causal. A 

symptom is any subjective sensation or perceived change in bodily 

function, such as low-back pain and fatigue, which only the 

individual can perceive. In contrast, a sign is objective evidence 

of disease that is evident to the health care provider, such as a 

bloody nose or a red eye. Symptoms are influenced by cognitive 

(thought) processes [Bogaerts et al. 2010]. Symptoms have been 

demonstrated to be more common when pollution or health 

threats are perceived, as at this school [Watson and Pennebaker 

1989; Williams and Lees-Haley 1993], and can be affected by fears, 

emotional triggers, and litigation [Lees-Haley and Brown 1992].

Of the general population, 86%–95% have one or more common 

symptoms during any given 2- to 4-week period, and the average 

adult reports a minimum of one symptom every 4 to 6 days 

[Barsky and Borus 1995]. These symptoms are rarely caused by 

serious illness. In fact, 15%–50% of primary care visits are for 

what is termed “medically unexplained symptoms” [Kroenke 2001; 

Kirmayer et al. 2004; Jackson et al. 2009; Bogaerts et al. 2010]. 

Medically unexplained symptoms are those for which no cause is 

found, even after thorough medical evaluation. Lipscomb et al. 

reported 1-year symptom prevalence rates from three populations 

in California [Lipscomb et al. 1992]. The top 10 symptoms were 

Discussion

 (continued)
Page 16 Health Hazard Evaluation Report 2010-0045-3129

sinus congestion or sneeze, irritated eyes, allergies or asthma, 

headaches, fatigue, difficulty sleeping, numbness or tingling in 

limbs, and skin problems, with rates ranging from 9.1% to 30.4%. 

A similar study in Australia found the top 10 symptoms were stuffy 

nose, headaches, fatigue, cough, itchy eyes, sore throat, skin rash, 

wheezing, trouble breathing, and nausea, with rates ranging from 

10.1% to 46.2% [Heyworth and McCaul 2001]. The U.S. EPA 

conducted a systematic survey of 100 randomly selected office 

buildings without known IEQ complaints in the United States to 

develop baseline data about U.S. office buildings [Brightman et 

al. 2008]. NIOSH conducted a similar study of 80 buildings with 

IEQ complaints [Malkin et al. 1996]. Occupants in both studies 

reported work-related symptoms. The rank order of symptoms 

was the same, but rates were significantly higher in the buildings 

with IEQ complaints. The most common work-related symptoms 

reported in both studies were dry, itching, or irritated eyes; unusual 

tiredness or fatigue; headache; tension or irritability; pain in back, 

neck, and shoulders; stuffy or runny nose, or sinus congestion; 

sneezing; sore or dry throat; and difficulty remembering things or 

concentrating. Forty-five percent of the employees in the randomly 

selected buildings reported at least one work-related symptom. These 

common symptoms in the general population and in buildings are 

also the most common symptoms reported by school employees.

The average adult has two to three upper respiratory infections 

per year [Benninger et al. 2003]. Sinusitis is the most frequently 

reported chronic disease in the United States, topping arthritis, 

allergies, and hypertension [Benson and Marano 1993]. 

Thirteen percent of U.S. adults reported physician-diagnosed 

sinusitis in 2008, according to the National Health Interview 

Survey [CDC 2009].

Several employees reported specific medical diagnoses that 

are unrelated to each other and to the school environment, 

for example, Lyme disease, Meniere’s disease, and vitamin 

D deficiency. Others had symptoms potentially suggestive 

of diagnosable medical conditions, such as change in hair 

texture, recurrent urinary frequency and urgency, and night 

sweats with fever and chills. It is important that employees seek 

appropriate medical care; such care could include a proper 

medical evaluation concerning work-relatedness of symptoms. 

Inappropriate attribution of these symptoms to the workplace 

can lead to delays in diagnosis and treatment or to harm from 

inappropriate treatment.

Discussion

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 17

The use of questionnaires to determine patient symptoms in the 

clinical setting has been repeatedly demonstrated to be prone to 

overendorsement of symptoms, which means they consistently 

result in a greater number of symptoms being reported than 

patients would have reported on their own, sometimes up to four 

times more [Homsi et al. 2006; Nolin et al. 2006; Stapleton and 

Mills 2008; Iverson et al. 2010]. Thus, the use of a list of over 30 

nonspecific symptoms by the private physician who set up the 

“clinic” likely led to more people being labeled as ill or as a “case” 

than would have been without the use of the list.

Two published studies claim that biotoxin-related illness is a 

condition with multiple-organ-system symptoms related to waterdamaged buildings [Shoemaker and House 2005; Shoemaker 

and House 2006]. Both studies used VCS to document and 

monitor the illness. Interpretation of these studies is hampered by 

methodological limitations, including a nonrepresentative sample, 

medical conditions that often present with multisystem symptoms 

(e.g., fibromyalgia and chronic fatigue syndrome), the lack of a 

comparison group, and poor exposure characterization. Replication 

of findings by other researchers is a critical element in confirming 

hypotheses such as this. NIOSH investigators have used VCS 

testing in an investigation to see if it could be used as a marker of 

effect from occupancy in water-damaged buildings. We concluded 

that VCS should not be used for clinical assessment of individuals 

exposed to water-damaged buildings [NIOSH 2010].

Many of the blood tests that school employees underwent for 

the private physician are not approved by the Food and Drug 

Administration, are for research purposes only, or were interpreted 

in a nonstandard manner. The laboratory reports that we reviewed 

also contained claims of validity and certification. Validity of a 

test’s performance characteristics means that the test measures 

what it says it will measure and that the laboratory methods give 

accurate, precise, and reliable results. While a test may be valid for 

measuring a particular substance, measurement of that substance 

may not be appropriate in the diagnosis or treatment of a specific 

illness. Laboratories, not tests, are certified under the Clinical 

Laboratory Improvement Amendments of 1988 (CLIA-88). Having 

a test performed in a CLIA-certified laboratory does not mean that 

the clinician used the test results appropriately for diagnosis.

While it is critical to pursue research to expand our knowledge 

base, it is also critical to present research or experimental 

Discussion

 (continued)
Page 18 Health Hazard Evaluation Report 2010-0045-3129

diagnostic procedures as such, with the full informed consent 

of each participant. While cholestyramine is unlikely to cause 

significant harm, all medications are approved for specific uses and 

all have potential side effects; therefore all medication use should 

be evaluated carefully. In addition, some medications, including 

erythropoietin, have risks determined by the Food and Drug 

Administration to be worthy of extra warnings, such as a black 

box warning [FDA 2009]. A black box warning is designed to call 

attention to serious or life-threatening risks of certain prescription 

drugs. We have serious concerns about employees being given this 

potentially harmful medication in a different way than described in 

the Food and Drug Administration approved drug label.

Discussion

 (continued)

Conclusions

We identified several correctable structural problems at the school. 

The main issue was that the crawl space under the renovated part 

of the school was a potential source of mold and dampness because 

of improper grading of the soil and inadequate ventilation. The 

high CO2

 concentrations indicated that, at times, the VAV HVAC 

system was not supplying enough outdoor air. Cat and dog allergen 

levels were elevated on some of the furniture that was sampled 

and could have contributed to work-related allergy symptoms of 

employees who have cat or dog allergies.

Many of the symptoms reported by employees, such as sinus 

problems and headaches, are common in offices, schools, and the 

general population. There is no evidence that more serious health 

problems reported by some staff are related to working in the 

building. These illnesses require medical diagnosis and treatment 

based on generally recognized and accepted medical practice, 

with the understanding that not all symptoms have a simple 

explanation. The lack of a ready explanation for all symptoms has 

led some employees to seek nonstandard medical care.
Health Hazard Evaluation Report 2010-0045-3129 Page 19

Recommendations

On the basis of our findings, we recommend the actions listed 

below to create a more healthful workplace. We encourage the 

school to use a labor-management health and safety committee 

or working group to discuss the recommendations in this report 

and develop an action plan. Those involved in the work can best 

set priorities and assess the feasibility of our recommendations 

for the specific situation at the school. Our recommendations 

are based on the hierarchy of controls approach. This approach 

groups actions by their likely effectiveness in reducing or removing 

hazards. In most cases, the preferred approach is to eliminate 

hazardous materials or processes and install engineering controls 

to reduce exposure or shield employees. Until such controls are 

in place, or if they are not effective or feasible, administrative 

measures and/or personal protective equipment may be needed.

Engineering Controls

Engineering controls reduce exposures to employees by removing 

the hazard from the process or placing a barrier between the 

hazard and the employee. Engineering controls are very effective 

at protecting employees without placing primary responsibility of 

implementation on the employee.

1. Address the movement of potentially contaminated air from the 

crawl space into the school building. This can be accomplished by 

maintaining negative pressure in the crawl space, adding a moisture 

barrier, and sealing the floor penetrations [IICRC 2006].

2. Test and balance the VAV boxes to ensure adequate ventilation to all 

occupied areas. ANSI/ASHRSE recommends an outdoor air supply 

rate of 10 CFM/person for classrooms. Use the highest-efficiency 

filters that the HVAC system can handle to reduce the potential for 

mold spores to enter the HVAC system. Do not use windows in the 

classrooms to reduce the entrance of unfiltered, unconditioned air.

3. Identify and fix indoor roof water leaks in a timely matter.

4. Regrade the soil around the building to ensure water does not collect 

at the foundation and in the crawl space.

5. Remove all porous items (such as carpeting and carpet padding, 

upholstery, wallpaper, ceiling tiles, paper, books, etc.) that have been 

wet for more than 48 hours and that cannot be thoroughly cleaned 

and dried. These items can remain a source of mold growth and 

should be removed from the school.
Page 20 Health Hazard Evaluation Report 2010-0045-3129

Administrative Controls

Administrative controls are management-dictated work practices 

and policies to reduce or prevent exposures to workplace hazards. 

The effectiveness of administrative changes in work practices 

for controlling workplace hazards is dependent on management 

commitment and employee acceptance. Regular monitoring and 

reinforcement is necessary to ensure that control policies and 

procedures are not circumvented in the name of convenience or 

production.

1. Institute a training program concerning the proper disposal of 

feminine hygiene products to address the plumbing issue in the 

women’s gymnasium locker room toilets.

2. Vacuum the furniture in the school with a HEPA vacuum on a 

regular basis to remove allergens.

3. Implement an IEQ management plan for the school district. An 

IEQ manager or administrator with clearly defined responsibilities, 

authority, and resources should be selected. This individual should 

have a good understanding of the building’s structure and function 

and should be able to effectively communicate with occupants. This 

is a proactive approach that can help prevent IEQ problems from 

occurring. Although comprehensive regulatory standards specific 

to IEQ have not been established, guidelines have been developed 

by organizations such as ASHRAE, NIOSH, and the U.S. EPA. 

The U.S. EPA has several publications on IEQ, including the 

IAQ Tools for Schools Action Kit which is available at http://www.

epa.gov/iaq/schools/toolkit.html. The Tools for Schools document 

discusses IEQ in some detail and includes information on common 

problems, investigative techniques, and solutions to specific 

problems. Additional resources include the U.S. EPA Healthy 

School Environments Assessment Tool, available at http://www.

epa.gov/schools/, which helps school districts establish and manage 

comprehensive school facility self-assessment programs. It contains 

an environmental health and safety checklist and is designed to 

be easily customized to reflect state and local requirements and 

policies. The basic elements of a good IEQ plan include the 

following:

● Properly operating and maintaining HVAC equipment, 

including accommodating occupants who work during hours 

when the HVAC system is routinely cycled off, to ensure that 

adequate ventilation is provided.

Recommendations

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 21

● Overseeing the activities of occupants and contractors that 

affect IEQ (e.g., housekeeping, pest control, maintenance, 

food preparation).

● Maintaining and ensuring effective and timely 

communication with occupants regarding IEQ.

● Educating building occupants and contractors about their 

responsibilities in relation to IEQ.

● Proactively identifying and managing projects that may affect 

IEQ (e.g., redecoration, renovation, relocation of personnel).

● Designating a school employee representative who can speak 

for the teachers and other employees and can assist with 

communication. 

Information on selecting IEQ consultants, if needed, is available 

from the AIHA Guidelines for Selecting an Indoor Air Quality 

Consultant.

4. Encourage employees with health concerns to seek evaluation 

and care from a physician who is residency trained and board 

certified in occupational medicine and is familiar with the types 

of exposures employees may have had and their health effects. 

You can locate these occupational medicine physicians through 

a variety of sources, including the Association of Occupational 

and Environmental Clinics, at http://www.aoec.org, and 

the American College of Occupational and Environmental 

Medicine, at http://www.acoem.org. The University of 

Maryland has a large occupational and environmental medicine 

clinic that could serve all your needs. It may be useful to provide 

the physician with a copy of this report.

5. Work with employee associations to inform employees about the 

limitations and potential risks of nonstandard medical tests and 

treatments. Refrain from participating in nonstandard medical 

testing and treatments without full knowledge and informed consent 

of risks and benefits. Consultation with staff from a university 

occupational and environmental medicine clinic is recommended.

6. Implement a formal system for reporting building concerns to the 

building manager. This system can be paper or electronic and should 

include a mechanism for the building manager to let staff know 

when and how the problem is fixed.

Recommendations

 (continued)
Page 22 Health Hazard Evaluation Report 2010-0045-3129

The following is a general recommendation that will improve 

IEQ in any facility and is not based upon specific problems we 

identified at the school.

7. Appoint an individual or group to research and approve cleaning 

materials used in your school district. Because there are no 

regulations regarding what can be labeled “environmentally 

friendly,” this individual or group will need to become 

knowledgeable about what cleaning materials are appropriate. 

Useful sources of information to help select the safest 

products include the National Institutes of Health database 

[http://householdproducts.nlm.nih.gov/], the Greenguard 

Environmental Institute [http://www.greenguard.org], Green 

Seal [http://www.greenseal.org/], and Terra Choice [http://www.

terrachoice.com/]. The Healthy School Network [http://www.

healthyschools.org/] has examples of other school districts that 

have revamped their housekeeping and maintenance programs.

Recommendations

 (continued)

References

AIHA [2005]. Chapter 8: Indoor allergens. In: Field guide for 

the determination of biological contaminant in environmental 

samples. Hung LL, Miller JD, Dillon KH, eds. Fairfax, VA: 

American Industrial Hygiene Association.

ANSI/ASHRAE [2010a]. Ventilation for acceptable indoor 

air quality. American National Standards Institute/ASHRAE 

standard 62.1-2010. Atlanta, GA: American Society of Heating, 

Refrigerating, and Air-Conditioning Engineers, Inc.

ANSI/ASHRAE [2010b]. Thermal environmental conditions 

for human occupancy. American National Standards Institute/

ASHRAE standard 55-2010. Atlanta, GA: American Society for 

Heating, Refrigerating, and Air-Conditioning Engineers, Inc.

Barsky AJ, Borus JF [1995]. Somatization and medicalization in the 

era of managed care. JAMA 274(24):1931-1934.

Benninger MS, Ferguson BJ, Hadley JA, Hamilos DL, Jacobs M, 

Kennedy DW, Lanza DC, Marple BF, Osguthorpe JD, Stankiewicz 

JA, Anon J, Denneny J, Emanuel I, Levine H [2003]. Adult 

chronic rhinosinusitis: definitions, diagnosis, epidemiology, and 

pathophysiology. Otolayngol Head Neck Surg 129(3 Suppl):S1-S32.
Health Hazard Evaluation Report 2010-0045-3129 Page 23

Benson V, Marano MA [1993]. Current estimates from the 

National Health Interview Survey, 1993, National Center for 

Health Statistics. Vital Health Stat 10(182).

Bogaerts K, Van Eylen L, Li W, Bresseleers J, Van Diest I, De 

Peuter S, Stans L, Decramer M, Van den Bergh O [2010]. Distorted 

symptom perception in patients with medically unexplained 

symptoms. J Abnorm Pschyol 119(1):226–234.

Brightman HS, Milton DK, Wypij D, Burge HA, Spengler JD 

[2008]. Evaluating building-related symptoms using the US EPA 

BASE study results. Indoor Air 18(4):335–345.

Brinkman NE, Haugland RA, Wymer LJ, Byappanahalli M, 

Whitman RL, Vesper SJ [2003]. Evaluation of a rapid, quantitative 

real-time PCR method for cellular enumeration of pathogenic 

Candida species in water. Appl Environ Microbiol 69(3):1775–

1782.

CDC [2009]. Summary Health Statistics for U.S. Adults: National 

Health Interview Survey,2008. available at http://www.cdc.gov/

nchs/nhis/nhis_series.htm. Date accessed: March 2011.

FDA [2009]. Public Health Advisory: erythropoiesis-stimulating 

agents (ESAs). Available at http://www.fda.gov/ForConsumers/

ByAudience/ForPatientAdvocates/HIVandAIDSActivities/

ucm124262.htm. Date accessed: March 2011.

Haugland RA, Brinkman NE, Vesper SJ [2002]. Evaluation of 

rapid DNA extraction methods for the quantitative detection 

of fungal cells using real time PCR analysis. J Microbiol Meth 

50(3):319–323.

Haugland RA, Varma M, Wymer LJ, Vesper SJ [2004]. Quantitative 

PCR of selected Aspergillus, Penicillium and Paecilomyces species. 

Sys Appl Microbiol 27(2):198–210.

Heyworth J, McCaul K [2001]. Prevalence of non-specific health 

symptoms in South Australia. Int J Environ Health Res 11(4):291-

298.

Homsi J, Walsh D, Rivera N, Rybicki LA, Nelson KA, Legrand SB, 

Davis M, Naughton M, Gvozdjan D, Pham H [2006]. Symptom 

evaluation in palliative medicine: patient report vs. systematic 

assessment. Support Care Cancer 14(5):444–453.

References

 (continued)
Page 24 Health Hazard Evaluation Report 2010-0045-3129

IICRC [2006]. Standard and reference guide for professional water 

damage restoration, IICRC 500. Vancouver, Washington: Institute 

of Inspection, Cleaning, and Restoration. ANSI/IICRC S500-

2006.

IOM [2000]. Executive Summary. In: Clearing the air: asthma 

and indoor air exposure. Institute of Medicine, National Academy 

Press, Washington, DC. pp. 1–18.

Iverson GL, Brooks BL, Ashton VL, Lange RT [2010]. Interview 

versus questionnaire symptom reporting in people with the 

postconcussion syndrome. J Head Trauma Rehab 25(1):23–30.

Jackson JL, George S, Hinchey S [2009]. Medically unexplained 

physical symptoms. J Gen Intern Med 24(4):540–542.

Kirmayer LJ, Groleau D, Looper KJ, Dominice Dao M [2004]. 

Explaining medically unexplained symptoms. Can J Psychiatry 

49(10):663–672.

Kroenke K [2001]. Studying symptoms: sampling and measurement 

issues. Ann Intern Med 134(9 part 2):844–853.

Lees-Haley PR, Brown RS [1992]. Bias in perception and reporting 

following a perceived toxic exposure. Percept Mot Skills 75(2):531–

544.

Liccardi G, D’Amato G, Russo M, Canonica GW, D’Amato L, De 

Martino M, Passalacqua G [2003]. Focus on cat allergen (Fel d 1): 

immunological and aerodynamic characteristics, modality of airway 

sensitization and avoidance strategies. Int Arch Allergy Immunol 

132(1):1–12.

Lipscomb JA, Satin KP, Neutra RR [1992]. Reported symptom 

prevalence rates from comparison populations in community-based 

environmental studies. Arch Environ Health 47(4)263–269.

Macher JM, Tsai FC, Burton LE, Liu KS [2005]. Concentrations of 

cat and dust-mite allergens in dust samples from 92 large US office 

buildings from the BASE Study. Indoor Air 15(Suppl 9):82–88.

References

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 25

Malkin R, Wicox T, Sieber WK [1996]. The National Institute for 

Occupational Safety and Health indoor environmental evaluation 

experience. Part two: symptom prevalence. Appl Occup Environ 

Hyg 11(6):540–545.

Meklin T, Haugland RA, Reponen T, Varma M, Lummus Z, 

Bernstein D, Wymer LJ, Vesper SJ [2004]. Quantitative PCR 

analysis of house dust can reveal abnormal mold conditions. J 

Environ Monit 6(7):615-20.

NIOSH [2010]. Health hazard evaluation report: comparison 

of mold exposures, work-related symptoms, and visual contrast 

sensitivity between employees at a severely water-damaged school 

and employees at a school without significant water damage, New 

Orleans, LA. By Thomas G, Burton NC, Mueller C, Page E. 

Cincinnati, OH: U.S. Department of Health and Human Services, 

Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health, NIOSH HETA No. 2005-0135-

3116.

Nolin P, Villemure R, Heroux L [2006]. Determining long-term 

symptoms following mild traumatic brain injury: method of 

interview affects self-report. Brain Inj 20(11):1147–1164.

Shoemaker RC, House DE [2005]. A time-series study of sick 

building syndrome: chronic, biotoxin-associated illness from 

exposure to water-damaged buildings. Neurotoxicol Teratol 

27(1):29–46.

Shoemaker RC, House DE [2006]. Sick building syndrome and 

exposure to water-damaged buildings: time series study, clinical 

trial and mechanisms. Neurotoxicol Teratol 28(5):573–588.

Stapleton R, Mills R [2008]. Role of open-ended questionnaires in 

patients with balance symptoms. J Laryngol Otol 122(2):139–144.

Tranter DC, Wobbema AT, Norlien K, Dorschner DF [2009]. 

Indoor allergens in Minnesota schools and child care centers. J 

Occup Environ Hyg 6(9):582–591.

U.S. EPA [2010]. Ozone generators that are sold as air cleaners. 

United States Environmental Protection Agency. [http://www.epa.

gov/iaq/pubs/ozonegen.html]. Date accessed: March 2011.

References

 (continued)
Page 26 Health Hazard Evaluation Report 2010-0045-3129

Vesper SJ, McKinstry C, Yang C, Haugland RA, Kercsmar CM, 

Yike I, Schluchter MD, Kirchner HL, Sobolewski J, Allan TM, 

Dearborn DG [2006]. Specific molds associated with asthma. J 

Occup Environ Med 48(8):852–858.

Vesper S, McKinstry C, Haugland R, Wymer L, Bradham K, 

Ashley P, Cox D, Dewalt G, Friedman W [2007]. Development of 

an environmental relative moldiness index for US homes. J Occup 

Environ Med 49(8):829–833.

Watson D, Pennebaker JW [1989]. Health complaints, stress, and 

distress: Exploring the central role of negative affectivity. Psychol 

Rev 96(2):234–254.

Williams CW, Lees-Haley PR [1993]. Perceived toxic exposure: A 

review of four cognitive influences on perception of illness. J Soc 

Behav Pers 8(3):489–506.

References

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 27

Appendix A: Tables and Figures

Table A1. Allergens from dust samples collected on couch and office chairs

Location Cat (Fel d1) 

± CV* μg/g†

Dog (Can f1)

± CV μg/g

Dust Mite (Der f1) 

± CV μg/g

Dust Mite (Der p1) 

± CV μg/g

Teachers’ Lounge, 

near Room 16—

Couch

2.01 ± 0.21 2.6 ± 0.55 ND‡ ND

Room 116 4.07 ± 0.42 1.84 ± 0.39 ND ND

Room 115 1.45 ± 0.15 0.49 ± 0.01 ND ND

Room 129 0.61 ± 0.063 1.4 ± 0.3 ND 0.51 ± 0.13

Room 122 3.59 ± 0.37 1.27 ± 0.27 ND ND

Room Black Box 1.37 ± 0.14 2.33 ± 0.49 ND ND

Room 103 0.87 ± 0.09 2.1 ± 0.45 ND ND

Room 102 0.81 ± 0.084 1.24 ± 0.26 0.49 ± 0.14 ND

Room 202 0.96 ± 0.099 1.6 ± 0.34 ND ND

VP Front Office 1.3 ± 0.13 2.1 ± 0.45 ND ND

No cockroach allergen was detected in any of the samples at a limit of detection of 1.6 units of allergen per gram.

*CV – Coefficient of variation

†μg/g – microgram of allergen per gram of dust

‡ND – not detected
Page 28 Health Hazard Evaluation Report 2010-0045-3129

Appendix A: Tables and Figures

 (continued)

Table A2. Fungal spore equivalents in dust, per MSQPCR and ERMI analysis

Fungal species

Group 1

Room 

002B*

Room 

100A

Room 

101*

Room 

102*

Room 

105*

Aspergillus flavus/oryzae ND† ND ND ND ND

Aspergillus fumigatus ND 1 ND ND ND

Aspergillus niger 1 2 ND ND ND

 Aspergillus ochraceus ND ND ND ND ND

Aspergillus penicillioides 4 590 ND ND 9

Aspergillus restrictus ND 15 ND ND ND

Aspergillus sclerotiorum ND ND ND ND ND

Aspergillus sydowii ND ND ND ND ND

Aspergillus unguis ND <1 ND ND ND

Aspergillus versicolor ND ND ND ND ND

Aureobasidium pullulans 86 1800 ND 2200 ND

Chaetomium globosum ND 2 ND ND ND

Cladosporium sphaerospermum 64 66 ND 49 ND

Eurotium (Asp.) amstelodami 1 69 ND ND ND

Paecilomyces variotii ND ND ND ND ND

Penicillium brevicompactum ND 3 ND ND ND

Penicillium corylophilum ND 1 ND ND ND

Penicillium crustosum ND 30 ND ND ND

Penicillium purpurogenum ND ND ND ND ND

Penicillium spinulosum ND <1 ND ND 6

Penicillium variabile ND 21 ND ND ND

Scopulariopsis brevicaulis ND <1 ND ND ND

Scopulariopsis chartarum 1 1 ND ND ND

Stachybotrys chartarum ND ND ND ND ND

Trichoderma viride ND ND ND ND ND

Wallemia sebi 6 95 ND ND 300

Sum of the logs, group 1 6.02 16.73 0.00 5.03 4.21

Group 2

Acremonium strictum ND 1 ND ND ND

Alternaria alternate 11 34 ND ND 22

Aspergillus ustus ND ND ND ND ND

Cladosporium cladosporioides-1 190 970 240 300 310

Cladosporium cladosporioides-2 <1 6 ND ND 2

Cladosporium herbarum 4 37 ND 96 ND

Epicoccum nigrum 360 340 ND 350 64

Mucor amphibiorum 1 21 ND ND ND

Penicillium chrysogenum 2 24 ND ND ND

Rhizopus stolonifer ND 27 ND ND ND

Sum of the logs, group 2 6.78 13.53 2.38 7.00 5.94

ERMI values -0.76 3.2 -2.38 -1.97 -1.73
Health Hazard Evaluation Report 2010-0045-3129 Page 29

Appendix A: Tables and Figures

 (continued)

Table A2 (continued). Fungal spore equivalents in dust, per MSQPCR and ERMI analysis

Fungal species

Group 1

Room 

106*

Room 

107

Room 

116 NS

Room 

120

Room 

122*

Aspergillus flavus/oryzae ND† ND 1 ND ND

Aspergillus fumigatus ND ND 5 3 ND

Aspergillus niger ND ND 15 3 ND

 Aspergillus ochraceus ND ND 4 ND ND

Aspergillus penicillioides ND 1 100 13 ND

Aspergillus restrictus ND ND ND ND ND

Aspergillus sclerotiorum ND ND 2 ND ND

Aspergillus sydowii ND ND 1 1 ND

Aspergillus unguis ND ND 1 ND ND

Aspergillus versicolor ND ND 4 ND ND

Aureobasidium pullulans 2100 180 5500 630 1300

Chaetomium globosum ND ND 5 ND ND

Cladosporium sphaerospermum ND 11 150 14 ND

Eurotium (Asp.) amstelodami 6 <1 43 6 ND

Paecilomyces variotii 4 1 9 ND ND

Penicillium brevicompactum ND ND 29 ND ND

Penicillium corylophilum ND ND 17 1 ND

Penicillium crustosum ND ND 17 24 ND

Penicillium purpurogenum ND ND ND ND ND

Penicillium spinulosum ND ND 1 <1 ND

Penicillium variabile ND 24 190 ND ND

Scopulariopsis brevicaulis ND ND <1 ND ND

Scopulariopsis chartarum ND ND ND ND ND

Stachybotrys chartarum ND ND 7 1 ND

Trichoderma viride ND ND 11 ND ND

Wallemia sebi 30 22 330 73 ND

Sum of the logs, group 1 6.18 6.02 25.19 10.04 4.11

Group 2

Acremonium strictum ND ND 1 ND ND

Alternaria alternate ND 11 110 8 ND

Aspergillus ustus ND ND 1 ND ND

Cladosporium cladosporioides-1 82 190 3100 310 35

Cladosporium cladosporioides-2 <1 <1 15 2 ND

Cladosporium herbarum ND 4 310 17 ND

Epicoccum nigrum 26 360 1000 60 ND

Mucor amphibiorum 1 1 39 3 ND

Penicillium chrysogenum ND 2 7 11 ND

Rhizopus stolonifer ND ND 8 ND ND

Sum of the logs, group 2 3.32 6.78 15.54 8.22 1.54

ERMI values 2.86 -0.76 9.65 1.82 2.57
Page 30 Health Hazard Evaluation Report 2010-0045-3129

Appendix A: Tables and Figures

 (continued)

Table A2 (continued). Fungal spore equivalents in dust, per MSQPCR and ERMI analysis

Fungal species

Group 1

Room 

122 NS

Room 

127 NS

Room 

130 NS

Boiler 

Room

Boiler 

Room

Aspergillus flavus/oryzae ND† ND 3 ND ND

Aspergillus fumigatus 7 5 3 7 ND

Aspergillus niger 11 5 130 2 ND

 Aspergillus ochraceus 5 ND ND ND ND

Aspergillus penicillioides 21 130 6 30 44

Aspergillus restrictus ND ND 21 ND ND

Aspergillus sclerotiorum ND 23 ND ND ND

Aspergillus sydowii ND 29 10 11 14

Aspergillus unguis 3 <1 <1 <1 ND

Aspergillus versicolor 2 2 2 13 5

Aureobasidium pullulans 13000 830 1600 2300 1000

Chaetomium globosum 7 ND 1 1 5

Cladosporium sphaerospermum 130 72 33 310 270

Eurotium (Asp.) amstelodami 19 1 22 8 4

Paecilomyces variotii 7 ND ND 5 1

Penicillium brevicompactum 24 ND 9 ND ND

Penicillium corylophilum 16 4 ND ND 2

Penicillium crustosum 15 ND 9 ND ND

Penicillium purpurogenum 5 ND ND 1 ND

Penicillium spinulosum 1 ND <1 ND ND

Penicillium variabile 79 12 44 220 90

Scopulariopsis brevicaulis 3 ND ND ND ND

Scopulariopsis chartarum ND ND ND ND 4

Stachybotrys chartarum ND ND ND 150 42

Trichoderma viride 5 ND 4 ND ND

Wallemia sebi 420 15 190 25 140

Sum of the logs, group 1 24.05 14.27 18.95 18.15 16.84

Group 2

Acremonium strictum 3 ND ND ND ND

Alternaria alternate 290 21 29 58 19

Aspergillus ustus 3 ND ND 16 15

Cladosporium cladosporioides-1 6000 360 500 440 270

Cladosporium cladosporioides-2 36 3 6 2 2

Cladosporium herbarum 360 9 38 150 34

Epicoccum nigrum 3400 110 360 540 330

Mucor amphibiorum 52 1 2 4 2+

Penicillium chrysogenum 5 8 2 ND 2

Rhizopus stolonifer 5 ND 1 ND ND

Sum of the logs, group 2 17.97 8.25 9.68 11.41 10.74

ERMI values 6.08 6.02 9.27 6.74 6.10
Health Hazard Evaluation Report 2010-0045-3129 Page 31

Appendix A: Tables and Figures

 (continued)

Table A2 (continued). Fungal spore equivalents in dust, per MSQPCR and ERMI analysis 

Fungal species

Group 1

Room 

131 NS

Room 

136

Room 

142

Room 

143

Room 

143 NS

Aspergillus flavus/oryzae 2 ND† ND ND 29

Aspergillus fumigatus 4 ND ND 3 38

Aspergillus niger 13 15 ND ND 39

 Aspergillus ochraceus 7 ND ND 4 20

Aspergillus penicillioides 63 25 5 14 340

Aspergillus restrictus ND ND ND ND 52

Aspergillus sclerotiorum 1 ND ND ND 51

Aspergillus sydowii 5 ND ND ND 2

Aspergillus unguis <1 ND ND ND <1

Aspergillus versicolor 4 ND ND ND 16

Aureobasidium pullulans 5000 1300 61 1100 8400

Chaetomium globosum 3 ND ND ND 3

Cladosporium sphaerospermum 130 76 15 10 620

Eurotium (Asp.) amstelodami 44 ND ND 3 360

Paecilomyces variotii 6 ND ND ND 10

Penicillium brevicompactum 9 59 3 ND 94

Penicillium corylophilum 4 ND 1 ND 24

Penicillium crustosum 12 ND ND ND 16

Penicillium purpurogenum ND ND ND ND 2

Penicillium spinulosum <1 ND ND ND 1

Penicillium variabile 69 ND ND ND 66

Scopulariopsis brevicaulis 1 ND <1 ND 4

Scopulariopsis chartarum 5 ND ND ND 9

Stachybotrys chartarum 8 ND ND ND 2

Trichoderma viride 3 ND ND ND 7

Wallemia sebi 490 ND 27 19 720

Sum of the logs, group 1 23.91 9.34 5.58 8.03 36.37

Group 2

Acremonium strictum 2 ND ND <1 10

Alternaria alternate 120 73 11 ND 260

Aspergillus ustus 1 ND ND ND ND

Cladosporium cladosporioides-1 2300 1600 180 85 12000

Cladosporium cladosporioides-2 10 6 1 <1 9

Cladosporium herbarum 180 ND 7 ND 2000

Epicoccum nigrum 1200 530 150 1 4600

Mucor amphibiorum 19 ND 2 ND 48

Penicillium chrysogenum 6 ND 1 ND 4

Rhizopus stolonifer 5 ND 2 ND 3

Sum of the logs, group 2 14.84 8.56 6.93 1.93 17.74

ERMI values 9.07 0.78 -1.35 6.10 18.63
Page 32 Health Hazard Evaluation Report 2010-0045-3129

Appendix A: Tables and Figures

 (continued)

Table A2 (continued). Fungal spore equivalents in dust, per MSQPCR and ERMI analysis

Fungal species 

Group 1

Room 

210 NS

Room 

211 NS

Room 

213 NS

Room 

217 NS

Aspergillus flavus/oryzae 3 <1 4 2

Aspergillus fumigates 2 4 3 4

Aspergillus niger 18 44 18 140

 Aspergillus ochraceus ND† 5 4 ND

Aspergillus penicillioides 15 23 17 15

Aspergillus restrictus 22 31 ND ND

Aspergillus sclerotiorum 2 1 2 ND

Aspergillus sydowii 2 25 3 2

Aspergillus unguis ND 1 <1 1

Aspergillus versicolor ND 2 2 2

Aureobasidium pullulans 5300 7000 2600 6800

Chaetomium globosum 6 33 3 2

Cladosporium sphaerospermum 81 58 51 64

Eurotium (Asp.) amstelodami 23 19 11 7

Paecilomyces variotii 13 11 3 3

Penicillium brevicompactum 6 10 7 23

Penicillium corylophilum 4 4 2 4

Penicillium crustosum 6 14 7 15

Penicillium purpurogenum ND ND 1 1

Penicillium spinulosum <1 1 <1 1

Penicillium variabile 16 10 13 27

Scopulariopsis brevicaulis <1 1 <1 <1

Scopulariopsis chartarum ND 1 ND 1

Stachybotrys chartarum 22 2 1 ND

Trichoderma viride 4 1 1 ND

Wallemia sebi 390 170 100 88

Sum of the logs, group 1 21.93 23.22 17.48 18.61

Group 2

Acremonium strictum <1 1 <1 2

Alternaria alternate 140 160 70 140

Aspergillus ustus 2 34 ND 7

Cladosporium cladosporioides-1 1100 1500 1200 1700

Cladosporium cladosporioides-2 13 62 25 14

Cladosporium herbarum 390 290 220 240

Epicoccum nigrum 100 1300 610 1700

Mucor amphibiorum 18 23 18 10

Penicillium chrysogenum 14 14 7 4

Rhizopus stolonifer 47 <1 4 <1

Sum of the logs, group 2 16.27 16.78 14.17 14.89

ERMI values 5.66 6.44 3.31 3.72

*low sample weight

†ND = not detected
Health Hazard Evaluation Report 2010-0045-3129 Page 33

Appendix A: Tables and Figures

 (continued)

Figure A1. Graph of CO2, CO, Temperature, and RH for Room 102.

Figure A2. Graph of CO2

, CO, Temperature, and RH for Room 116.
Page 34 Health Hazard Evaluation Report 2010-0045-3129

Appendix A: Tables and Figures

 (continued)

Figure A3. Graph of CO2, CO, Temperature, and RH for Room 122.

Figure A4. Graph of CO2, CO, Temperature, and RH for Room 136.
Health Hazard Evaluation Report 2010-0045-3129 Page 35

Appendix A: Tables and Figures

 (continued)

Figure A5. Graph of CO2, CO, Temperature, and RH for Room 202.
Page 36 Health Hazard Evaluation Report 2010-0045-3129

Appendix B: Occupational Exposure Limits and Health Effects

 

Microbial Contamination

Exposure to microbes is not unique to the indoor environment. No environment, indoors or out, 

is completely free from microbes, not even a surgical operating room. Remediation of microbial 

contamination may improve IEQ conditions even though a specific cause-effect relationship is not 

determined. NIOSH investigators routinely recommend the remediation of observed microbial 

contamination and the correction of situations that are favorable for microbial growth and 

bioaerosol dissemination.

Mold

The types and severity of symptoms related to exposure to mold in the indoor environment 

depend in part on the extent of the mold present, the extent of the individual’s exposure, and the 

susceptibility of the individual (for example, whether they have preexisting allergies or asthma). In 

general, excessive exposure to fungi may produce health problems by several primary mechanisms, 

including allergy or hypersensitivity, infection, and toxic effects. Additionally, molds produce a 

variety of VOCs, the most common of which is ethanol, that have been postulated to cause upperairway irritation. However, as discussed above, potential irritant effects of VOCs from exposure to 

mold in the indoor environment are not well understood. Evidence also shows that exposure to 

fungal fragments that can contain allergens, toxins, and (1→3)-β-D-glucan may occur [Górney et al. 

2002; Brasel et al. 2005; Reponen et al. 2006].

Allergic responses are the most common type of health problem associated with exposure to molds. 

These health problems may include sneezing; itching of the nose, eyes, mouth, or throat; nasal 

stuffiness and runny nose; and red, itchy eyes. Repeated or single exposure to mold or mold spores 

may cause previously nonsensitized individuals to become sensitized. Molds can trigger asthma 

symptoms (shortness of breath, wheezing, cough) in persons who are allergic to mold. In the 2004 

report, “Damp Indoor Spaces and Health,” the IOM found sufficient evidence of an association 

between mold or dampness indoors and nasal and throat symptoms, asthma symptoms in sensitized 

asthmatics, wheeze, cough, and hypersensitivity pneumonitis in susceptible persons [IOM 2004]. 

The IOM found limited or suggestive evidence of an association between lower respiratory illness 

in healthy children and damp indoor spaces. There was inadequate or insufficient evidence 

to determine whether an association exists between damp indoor spaces and dyspnea, airflow 

obstruction in healthy persons, mucous membrane irritation, skin symptoms, chronic obstructive 

pulmonary disease, asthma development, inhalation fevers in nonoccupational settings, fatigue, 

cancer, reproductive effects, neuropsychiatric effects, lower respiratory illness in healthy adults, 

gastrointestinal problems, rheumatologic or immune problems, or acute idiopathic pulmonary 

hemorrhage in infants. No health conditions met the level of evidence for causation. In 2009, 

WHO published guidelines for protection of public health from mold and other exposures in 

damp buildings [WHO 2009]. Based on its review of the scientific literature for this report, the 

WHO concluded that there was sufficient epidemiological evidence that occupants of damp 

buildings are at risk of developing upper and lower respiratory tract symptoms (including cough, 

wheeze, and dyspnea), respiratory infections, asthma, and exacerbation of asthma. The WHO also 
Health Hazard Evaluation Report 2010-0045-3129 Page 37

concluded that limited evidence suggests associations between bronchitis and allergic rhinitis and 

damp buildings. They noted clinical evidence that exposure to mold and other microbial agents in 

damp buildings is associated with hypersensitivity pneumonitis.

People with weakened immune systems (immune-compromised or immune-suppressed individuals) 

may be more vulnerable to infections by molds. For example, Aspergillus fumigatus is a fungal 

species that has been found almost everywhere on every conceivable type of substrate. It has been 

known to infect the lungs of immune-compromised individuals after inhalation of the airborne 

spores [Wald and Stave 1994; Brandt et al. 2006]. Healthy individuals are usually not vulnerable to 

infections from airborne mold exposure.

No exposure guidelines for mold in air exist, so it is not possible to distinguish between “safe” 

and “unsafe” levels of exposure. Nevertheless, the potential for health problems is an important 

reason to prevent indoor mold growth and to remediate any indoor mold contamination. Moisture 

intrusion, along with nutrient sources such as building materials or furnishings, allows mold to 

grow indoors, so it is important to keep the building interior and furnishings dry. NIOSH concurs 

with the U.S. EPA’s recommendations to remedy mold contamination in indoor environments 

([http://www.epa.gov/iaq/molds /mold_remediation.html) [Redd SC 2002; US EPA 2001]. 

Additional information on health effects and mold remediation can be found in the Centers for 

Disease Control and Prevention document Mold Prevention Strategies and Possible Health Effects in 

the Aftermath of Hurricanes and Major Floods (http://www.cdc.gov/mmwr/preview/ mmwrhtml/

rr5508a1.htm).

Standards specific to the nonindustrial indoor environment do not exist. Measurement of indoor 

environmental contaminants has seldom proved helpful in determining the cause of symptoms, 

except where there are unusual sources or a proven relationship between specific exposures and 

disease. With few exceptions, concentrations of frequently measured chemical substances in the 

indoor work environment fall well below the recommended OELs published by NIOSH [NIOSH 

2005], ACGIH [ACGIH 2010], and AIHA [AIHA 2010], as well as the mandatory PELs set by 

OSHA [29 CFR 1910 (general industry)]. ANSI/ASHRAE has published recommended building 

ventilation and thermal comfort guidelines [ANSI/ASHRAE 2010a; ANSI/ASHRAE 2010b]. The 

ACGIH and AIHA have also developed a manual of guidelines for approaching investigations of 

building-related symptoms that might be caused by airborne living organisms or their effluents 

[ACGIH 1999; AIHA 2008]. Other resources that provide guidance for establishing acceptable 

IEQ are available through U.S. EPA at http://www.epa.gov/iaq, especially the U.S. EPA Indoor 

Air Quality Tools for Schools (http://www.epa.gov/iaq/schools/) and the joint U.S. EPA/NIOSH 

document Building Air Quality, A Guide for Building Owners and Facility Managers (http://www.epa.

gov/iaq/largebldgs/baqtoc.html).

Appendix B: Occupational Exposure Limits and Health Effects

 (continued)
Page 38 Health Hazard Evaluation Report 2010-0045-3129

Heating, Ventilating, and Air-Conditioning

One of the most common deficiencies in the indoor environment is the improper operation and 

maintenance of ventilation systems and other building components [Rosenstock 1996]. NIOSH 

investigators have found that correcting HVAC problems often reduces reported symptoms. The 

majority of studies of ventilation rates and building occupant symptoms have shown that rates 

below 10 Ls-1/person (which equates to 20 CFM per person) are associated with one or more 

health symptoms [Seppanen et al. 1999]. Moreover, higher ventilation rates, from 10 Ls-1/person 

up to 20 Ls-1/person, have been associated with further significant decreases in the prevalence 

of symptoms [Seppanen et al. 1999]. Thus, improved HVAC operation and maintenance, higher 

ventilation rates, and comfortable temperature and RH can all potentially serve to improve 

symptoms without ever identifying any specific cause-effect relationships. When conducting an 

IEQ evaluation, NIOSH investigators often measure ventilation and comfort indicators, such as 

CO2, temperature, and RH, to provide information relative to the functioning and control of 

HVAC systems.

Carbon Dioxide

CO2 is a normal constituent of exhaled breath and is not considered a building air pollutant. It can be 

used as an indicator of whether sufficient quantities of outdoor air are being introduced into an occupied 

space for acceptable odor control. However, CO2 is not an effective indicator of ventilation adequacy 

if the ventilated area is not occupied at its usual occupant density at the time the CO2 is measured. 

ASHRAE notes in an informative appendix to standard 62.1 that indoor CO2 concentrations no greater 

than 700 ppm above outdoor CO2 concentrations will satisfy a substantial majority (about 80%) of visitors 

with regard to odor from sedentary building occupants (body odor) [ANSI/ASHRAE 2010b]. Elevated 

CO2 concentrations suggest that other indoor contaminants may also be increased. If CO2 concentrations 

are elevated, the amount of outdoor air introduced into the ventilated space may need to be increased. 

When CO2 concentrations are used as an indicator to determine outdoor air requirements, ventilation 

system designs that rely on duct-mounted CO2 sensors should have some form of ventilation efficiency 

documentation that relates concentration values observed at the duct location with those observed within 

the breathing zone of the occupied space.

Temperature and Relative Humidity

Temperature and RH measurements are often collected as part of an IEQ evaluation because 

these parameters affect the perception of comfort in an indoor environment. The perception 

of thermal comfort is related to one’s metabolic heat production, the transfer of heat to the 

environment, physiological adjustments, and body temperature [NIOSH 1986]. Heat transfer 

from the body to the environment is influenced by factors such as temperature, humidity, air 

movement, personal activities, and clothing. The ANSI/ASHRAE Standard 55-2010, Thermal 

Environmental Conditions for Human Occupancy, specifies conditions in which 80% or more of 

the occupants would be expected to find the environment thermally acceptable [ANSI/ASHRAE 

2010a]. Assuming slow air movement and 50% RH, the operative temperatures recommended by 

Appendix B: Occupational Exposure Limits and Health Effects

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 39

ANSI/ASHRAE range from 68.5oF to 76oF in the winter, and from 75oF to 80.5oF in the summer. 

The difference between the two is largely due to seasonal clothing selection. ANSI/ASHRAE also 

recommends that RH be maintained at or below 65% [ANSI/ASHRAE 2010a]. Excessive humidity 

can promote the excessive growth of microorganisms and dust mites.

Appendix B: Occupational Exposure Limits and Health Effects

 (continued)
Page 40 Health Hazard Evaluation Report 2010-0045-3129

References

ACGIH [1999]. Bioaerosols: assessment and control. Cincinnati, OH: American Conference of 

Governmental Industrial Hygienists.

ACGIH [2010]. 2010 TLVs® and BEIs®: threshold limit values for chemical substances and physical 

agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

AIHA [2008]. Recognition, evaluation, and control of indoor mold. Prezant B, Weekes DM, Miller JD 

eds. Fairfax, VA: American Industrial Hygiene Association.

AIHA [2010]. 2010 Emergency response planning guidelines (ERPG) & workplace environmental 

exposure levels (WEEL) handbook. Fairfax, VA: American Industrial Hygiene Association.

ANSI/ASHRAE [2010a]. Thermal environmental conditions for human occupancy. American 

National Standards Institute/ASHRAE standard 55-2010. Atlanta, GA: American Society for Heating, 

Refrigerating, and Air-Conditioning Engineers, Inc.

ANSI/ASHRAE [2010b]. Ventilation for acceptable indoor air quality. American National Standards 

Institute/ASHRAE standard 62.1-2010. Atlanta, GA: American Society of Heating, Refrigerating, and 

Air-Conditioning Engineers, Inc.

Brandt M, Brown C, Burkhart J, Burton N, Cox-Ganser J, Damon S, Falk H, Fridkin S, Garbe P, 

McGeehin M, Morgan J, Page E, Rao C, Redd S, Sinks T, Trout D, Wallingford K, Warnock D, 

Weissman D [2006]. Mold prevention strategies and possible health effects in the aftermath of 

hurricanes and major floods. MMWR 55(RR-8):1–27.

Brasel TL, Martin JM, Carriker CG, Wilson SC, Straus DC [2005]. Detection of airborne Stachybotrys 

chartarum macrocyclic trichothecene mycotoxins in the indoor environment. Appl Environ Microbiol 

71(11):7376–7388.

CFR. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Office of the 

Federal Register.

Górny RL, Reponen T, Willeke K, Schmechel D, Robine E, Boissier M, Grinshpun SA [2002]. Fungal 

fragments as indoor air biocontaminants. Appl Environ Microbiol 68(7):3522–3531.

IOM [2004]. Human health effects associated with damp indoor environments. In: Damp indoor spaces 

and health. Institute of Medicine, National Academy Press, Washington, DC. pp. 183–269.

Appendix B: Occupational Exposure Limits and Health Effects

 (continued)
Health Hazard Evaluation Report 2010-0045-3129 Page 41

NIOSH [1986]. Criteria for a recommended standard: occupational exposure to hot environments, 

revised criteria. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease 

Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 

86–13.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health 

and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational 

Safety and Health, DHHS (NIOSH) Publication No. 2005–149. [http://www.cdc.gov/niosh/npg/]. 

Date accessed: March 2011.

Redd SC [2002]. State of the science on molds and human health. Statement for the Record Before the 

Subcommittee on Oversight and Investigations and Housing and Community Opportunity, Committee 

on Financial Services, United States House of Representatives. Atlanta, GA: U.S. Department of 

Health and Human Services, Centers for Disease Control and Prevention.

Reponen T, Seo S-C, Iossifova Y, Adhikari A, Grinshpun SA [2006]. New field-compatible method 

for collection and analysis of β-glucan in fungal fragments. Abstracts of the International Aerosol 

Conference, St. Paul, Minnesota, p. 955.

Rosenstock L [1996]. NIOSH Testimony to the U.S. Department of Labor on indoor air quality. 

Applied Occupational and Environmental Hygiene 11(12):1365–1370.

Seppanen OA, Fisk WJ, Mendell MJ [1999]. Association of ventilation rates and CO2 concentrations 

with health and other responses in commercial and institutional buildings. Indoor Air 9(4):226–252.

U.S. EPA [2001]. Mold remediation in schools and commercial buildings. Washington, DC: United 

States Environmental Protection Agency, Office of Air and Radiation, Indoor Environments Division. 

EPA Publication No. 402–K–01–001.

Wald P, Stave G [1994]. Fungi. In: Physical and biological hazards of the workplace. New York: Van 

Nostrand Reinhold, p. 394.

WHO [2009]. WHO guidelines for indoor air quality: dampness and mould. Geneva, Switzerland: 

World Health Organization. [http://www.euro.who.int/document/e92645.pdf]. Date accessed: 

March 2011.

Appendix B: Occupational Exposure Limits and Health Effects

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Health Hazard Evaluation Report 2010-0045-3129 Page 43

Acknowledgments and

Availability of Report

The Hazard Evaluations and Technical Assistance Branch (HETAB) 

of the National Institute for Occupational Safety and Health 

(NIOSH) conducts field investigations of possible health hazards 

in the workplace. These investigations are conducted under the 

authority of Section 20(a)(6) of the Occupational Safety and Health 

Act of 1970, 29 U.S.C. 669(a)(6), which authorizes the Secretary of 

Health and Human Services, following a written request from any 

employer or authorized representative of employees, to determine 

whether any substance normally found in the place of employment 

has potentially toxic effects in such concentrations as used or found. 

HETAB also provides, upon request, technical and consultative 

assistance to federal, state, and local agencies; labor; industry; and 

other groups or individuals to control occupational health hazards 

and to prevent related trauma and disease.

The findings and conclusions in this report are those of the authors 

and do not necessarily represent the views of NIOSH. Mention 

of any company or product does not constitute endorsement by 

NIOSH. In addition, citations to websites external to NIOSH do not 

constitute NIOSH endorsement of the sponsoring organizations or 

their programs or products. Furthermore, NIOSH is not responsible 

for the content of these websites. All Web addresses referenced in 

this document were accessible as of the publication date.

This report was prepared by Elena Page, Nancy Burton, Melody 

Kawamoto, and R. Todd Niemeier of HETAB, Division of 

Surveillance, Hazard Evaluations and Field Studies. Analytical 

support was provided by Steven Vesper, United States 

Environmental Protection Agency, National Exposure Research 

Laboratory, Cincinnati, Ohio, and EmLabs P&K, Cherry Hill, New 

Jersey. Health communication assistance was provided by Stefanie 

Evans. Editorial assistance was provided by Seleen Collins. Desktop 

publishing was performed by Greg Hartle.

Copies of this report have been sent to employee and management 

representatives at the middle school, the state health department, 

and the Occupational Safety and Health Administration Regional 

Office. This report is not copyrighted and may be freely reproduced. 

The report may be viewed and printed at http://www.cdc.gov/

niosh/hhe/. Copies may be purchased from the National Technical 

Information Service at 5825 Port Royal Road, Springfield, Virginia 

22161.
Below is a recommended citation for this report:

NIOSH [2011]. Health hazard evaluation report: evaluation of health concerns in 

a public middle school – Virginia. By Page E, Burton N, Kawamoto M, Niemeier 

RT. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for 

Disease Control and Prevention, National Institute for Occupational Safety and 

Health, NIOSH HETA No. 2010-0045-3129.

To receive NIOSH documents or information about 

occupational safety and health topics, contact NIOSH at:

1-800-CDC-INFO (1-800-232-4636)

TTY: 1-888-232-6348

E-mail: cdcinfo@cdc.gov

or visit the NIOSH web site at: www.cdc.gov/niosh.

For a monthly update on news at NIOSH, subscribe to 

NIOSH eNews by visiting www.cdc.gov/niosh/eNews.

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