Evaluation of indoor 

environmental quality 

at an accounting 

office

Rachel Bailey, DO, MPH

Chris Piacitelli, MS, CIH

Stephen Martin, Jr., MS, PE

Jean Cox-Ganser, PhD

Health Hazard Evaluation Report

HETA 2011-0096-3176

Florida

April 2013

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health
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 2011-0096-3176 Page 1

Tables

Report Abbreviations.......................................................................2

Highlights of the NIOSH Health Hazard Evaluation.............3

Summary .............................................................................7

Introduction..........................................................................7

Background......................................................................... 8 

Methods...............................................................................9

Results...............................................................................10

Discussion .........................................................................24

Conclusions.......................................................................31

Recommendations.............................................................31

References ........................................................................34

Contents

Acknowledgements and Availability of Report...................65

Tables ................................................................................37

Figures Figures ..............................................................................42

Acknowledgments
Page 2 Health Hazard Evaluation Report 2011-0096-3176

μg Microgram

AHU Air handling unit

ANSI American National Standards Institute 

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

cfm Cubic feet per minute

cfu/g Colony forming units per gram 

CO Carbon monoxide

CO2 Carbon dioxide

DOAS Dedicated outdoor air system

EPA U.S. Environmental Protection Agency 

°F Degrees Fahrenheit

FID Flame ionization detector

HEPA High-efficiency particulate air

HVAC Heating, ventilating, and air-conditioning

H2S Hydrogen sulfide 

IEQ Indoor environmental quality

L/s Liters per second

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OSHA Occupational Safety and Health Administration

PID Photionization detector

ppm Parts per million

RH Relative humidity

SW Southwest

VOC Volatile organic compound

Abbreviations
Health Hazard Evaluation Report 2011-0096-3176 Page 3

What NIOSH Did:

● We reviewed historical environmental reports.

● We visually assessed the office building and ventilation 

equipment on June 22-23, 2011.

● We took measurements of carbon dioxide, carbon monoxide, 

temperature, relative humidity, hydrogen sulfide, and volatile 

organic compounds in the air.

● We collected carpet dust samples from nine areas to analyze 

for microorganisms.

● We provided recommendations to the building occupants, 

building owner, building management, and consultants. 

What NIOSH Found:

● In the interior of the building we observed:

● ill-fitting weather stripping on exterior doors; 

● water-stained ceiling tiles, window sill, and walls;

● raised area on cloth wallpaper from a previous water 

leak; 

● neutral air flow between the men’s bathroom and 

hallway; 

● rust stains at roof lap joints in ceiling plenum; and

● portable air cleaner units.

● On the roof, we smelled a musty odor in two air-handling 

units and observed dust accumulation and visible mold 

(confirmed by sampling) in the supply ducts inside two airhandling units.

● We observed over-sized filters in air-handling units, dusty 

cooling coils, build-up in drain pans, and rusty areas. We also 

observed condensate water from coils draining incorrectly in 

one air-handling unit.

● Carpet dust sampling showed heavy microbial contamination 

in some areas. 

● Environmental reports from consultants prior to our visit 

reported the following findings: 

● stained ceiling tiles,

● moisture in drywall of Room 19 window,

● elevated relative humidity levels during some 

unoccupied periods,

● water stains on wall in Hall 5 from a reported roof 

leak,

In April 2011, employees 

requested a health hazard 

evaluation to investigate 

concerns about indoor 

environmental quality at 

an accounting office in 

Florida with a history of 

indoor dampness, mold 

growth, and buildingrelated symptoms among 

staff.

Highlights of the

NIOSH Health

Hazard Evaluation
Page 4 Health Hazard Evaluation Report 2011-0096-3176

Highlights of the

NIOSH Health

Hazard Evalution

(continued)

● visible water damage above baseboard close to exit 

door in Hall 11,

● wall cavity air sampling positive for fungal hyphae in 

Room 6 and fungi in Hall 11,

● vacuum cleaners without high-efficiency particulate 

air filters,

● ponding of water on a deteriorated section of the 

roof near a drain, 

● plant growth on the roof,

● low-efficiency filters in air-handling units,

● visible mold growth confirmed by microscopic 

analysis in some air-handling units,

● insulation wet to touch in some air-handling units,

● no Chinese drywall.

What has been done since the NIOSH Site 

Visit:

● Monitored temperature and relative humidity in five areas for 

several days.

● Tested 13 rooms for cat, dog, cockroach, and dust mite 

allergens.

● Performed concrete slab testing for moisture in Rooms 2, 21, 

27, and 29.

● Explored wall cavities in Halls 5 and 11 and Rooms 6, 10, 

and 12.

● Replaced drywall in Rooms 6 and 10 with suspect visible 

mold.

● Removed a vacuum that did not have a high-efficiency 

particulate air filter.

● Repaired window leak in Room 19.

● Increased exhaust fan air flow in the men’s bathroom.

● Removed carpet and replaced with ceramic tile in Room 6 

and Hall 5 and Hall 11.

● Replaced weather stripping around exterior doors at Hall 5 

and Hall 11.

● Replaced asphalt landing with concrete landing and installed 

a wider awning at Hall 5 door.

● Waterproofed back wall and installed new French drain 

along the wall.

● Re-graded foundation for better drainage.
Health Hazard Evaluation Report 2011-0096-3176 Page 5

Highlights of the

NIOSH Health

Hazard Evalution

(continued)

● Removed plants with offensive odor. 

● Replaced air-handling units 1 and 4 and some fiberglass 

ductwork.

● Steam-cleaned carpet.

● Relocated to new building when employees continued to 

have building-related symptoms.

What the Next Employer/Tenant Can Do:

● Use track-off floor mats at each doorway.

● Avoid the use of chair mats; if not feasible, use perforated 

chair mats.

● Keep paper and boxes off the floor as much as possible.

● Clean the carpet with a high-efficiency particulate air vacuum 

and ensure the vacuum is well-maintained.

● Avoid the use of biocides.

● Collect carpet dust for microbial testing to determine if the 

carpet cleaning was successful. If there is not a significant 

decrease in microbes, the carpet may need to be removed.

● Avoid the use of air cleaners.

● Encourage building occupants who experience worsening, 

persistent, or recurrent respiratory or other health symptoms 

that may be associated with being in the building to see their 

physician.

● Implement a fragrance-free policy. 

What the Building Manager/Owner Can Do:

● Perform routine maintenance of air-handling units.

● Routinely assess the building for water intrusion and damage 

and high relative humidity and correct these upon discovery.

● Promptly remove any future mold or moisture-damaged 

materials with appropriate containment. 

● Do not rely upon air sampling for mold since air 

concentrations cannot be interpreted with respect to health 

risk. 

● Keep a record of when and where mold or water-damaged 

materials are discovered and what has been done to promptly 

fix the problem.
Page 6 Health Hazard Evaluation Report 2011-0096-3176

Highlights of the

NIOSH Health

Hazard Evalution

(continued)

What Employees Can Do:

● Inform management of any water leaks, dampness, musty or 

moldy odors, or ventilation problems in the building.

● See a healthcare provider if you develop or have developed 

recurring or worsening respiratory symptoms or other health 

symptoms while working in the building.

● Let your supervisor know if your healthcare provider 

recommends relocation to another work area to prevent 

exposure to mold or dampness-related contaminants that 

may be causing or exacerbating your symptoms.

NIOSH considers 

dampness in occupied 

buildings a public 

health problem that 

requires remediation. 

NIOSH investigators 

found a history of 

dampness and mold 

growth in the building 

and recommended 

remediation measures, 

many of which were 

undertaken. 
Health Hazard Evaluation Report 2011-0096-3176 Page 7

On April 15, 2011, NIOSH received an employee request regarding 

headaches, fatigue, weakness, fever, chills, flu-like symptoms, 

shortness of breath, coughing, chronic sinusitis, sore throat, 

burning eyes, and difficulty concentrating in a water-damaged 

building. In June 2011, NIOSH investigators conducted a site visit. 

The majority of employees reported building-related symptoms. 

We found evidence of water damage inside the building and 

mold inside supply air ducts of two air handlers. Vacuumed 

carpet dust samples collected during the site visit showed a high 

burden of culturable fungi and bacteria. We provided a number of 

recommendations for remediation including addressing causes of 

water damage and replacing contaminated carpet and ductwork. 

Building management replaced two rooftop air handling units and 

some ductwork. The carpet was steam cleaned. Some building 

occupants continued to have symptoms, and the accounting 

company relocated to another building.

Summary

Keywords: NAICS 541211 (Offices of Certified Public 

Accountants), indoor environmental quality, IEQ, 

respiratory symptoms, dampness, mold, bacteria, 

ventilation, HVAC, carpet

Introduction In April 2011, the Health Hazard Evaluation (HHE) Program 

of the National Institute for Occupational Safety and Health 

(NIOSH) received a request to investigate concerns about the 

indoor environmental quality (IEQ) at an accounting office in 

Florida; at the same time we received the HHE request, we received 

inquiries from a Florida U.S. Senator regarding employee health 

concerns. The requestors reported odors and air quality problems 

throughout the offices. Health concerns included headaches, 

fatigue, weakness, fever, chills, flu-like-symptoms, shortness of 

breath, coughing, chronic sinusitis, dusty and metallic taste, 

irritated and sore throats, burning eyes, red eyes, and difficulty 

with thought processes.
Page 8 Health Hazard Evaluation Report 2011-0096-3176

The accounting firm resided in a two-tenant single-story building 

erected in 1984 near several other office buildings and strip malls. 

During the year prior to the firm’s 2007 occupancy of the space, it 

was completely gutted and renovated. Their offices occupied about 

7,500 square feet, or nearly two-thirds of the building, comprising 

45 rooms, of which six rooms were shared with a partner financial 

management firm. Most were single-occupancy rooms, although 

there were a few open-space cubicles and two reception areas. 

Additionally, there were two conference rooms, bathrooms, copy 

rooms, three storage rooms, a file room, and a kitchen/breakroom 

(Figure 1). There were approximately 30 workers in the accounting 

office.

The building was constructed on a concrete slab and had stuccofaced concrete block exterior walls with many windows (Figures 

2 and 3). Mineral-surfaced roll roofing covered the slightly 

sloped roof. Roof water flowed through drainpipes within the 

hanging ceiling plenum, exterior walls, and underground, and it 

emptied into a storm drainage manhole in the front parking lot 

(Figures 4-6). On the roof were eight heating, ventilating, and air 

conditioning (HVAC) air handling units (AHUs), five of which 

(AHU-1 through AHU-5) served the accounting office space 

(Figure 4). These HVAC units and the zones they served within 

the building are shown in Figure 1. 

The floors of the main reception area and nearby hallway were 

wood, those of the bathroom and kitchen were tile, and the 

remainder of the space had low-pile carpet (Figure 7). All interior 

walls were drywall covered with paint, with the exception of those 

in two offices on the northwest side that were covered with cloth 

wallpaper. The hanging ceiling was composed of acoustical fiber 

ceiling tiles, fluorescent lighting fixtures, and the HVAC system 

supply and return air grilles. Inside the ceiling plenum were the 

corrugated metal roof deck, steel roof trusses, electrical wiring 

and lighting, roof drain pipes, and the HVAC supply and return 

air ductwork (Figures 5, 8, 9 and 10). The main duct trunk lines 

connected to the AHUs were made of resin-bonded fiber glass 

formed into rigid, rectangular boards, faced on the outside with 

foil (Figure 9) and a fiber glass mat on the inside airstream surface 

(Figure 11). From these, round flexible ducts, wrapped with foillined insulation, extended to the supply and return grilles mounted 

in the ceiling (Figure 10). 

During the 2006-2007 rebuild, AHU-4 was replaced, as was all 

Background
Health Hazard Evaluation Report 2011-0096-3176 Page 9

ductwork for each HVAC system. The renovation also included 

the closure with concrete block of an opening for a garage-type 

door in Room 6 used by the previous engineering firm tenant for 

access to surveying equipment. 

Background (continued)

Methods We reviewed consultant reports of several IEQ evaluations (dated 

March 2008 through June 2011). On June 22 and 23, 2011, we 

made a walk-through evaluation of the accounting office. An 

environmental specialist from the local county health department 

joined us during part of the evaluation. 

We visited each room of the accounting office and those shared 

with the financial management firm. In nearly half of the rooms 

and outside, we took measurements of temperature, relative 

humidity, carbon dioxide (CO2

) and carbon monoxide (CO) with 

a VelocicalcTM multi-function ventilation meter, Model 9555-X 

(TSI, Inc., Shoreview, MN). Additionally, because a recent 

investigation had some positive findings for hydrogen sulfide 

(H2

S), we sampled for the compound with a GasBadge ProTM single 

gas monitor for H2

S (Industrial Scientific Corp., Oakdale, PA). 

The health department environmental specialist simultaneously 

collected volatile organic compound (VOC) measurements with 

a TVA-1000 Toxic Vapor AnalyzerTM (Thermo Environmental 

Instruments, Inc., Franklin, MA). This instrument has both a 

photoionization detector (PID) and a flame ionization detector 

(FID) for measurements. We used a Model DG-2 digital pressure 

gauge (Energy Conservatory, Minneapolis, MN) to check the air 

flow between the bathrooms and adjacent hallway.

As we visited each room, we looked for evidence of water damage, 

water incursion, visible mold, and other potential IEQ problems. 

We made similar inspections of the ceiling plenum. Near the floor 

of several rooms, we used a hand saw to cut out approximately 8 

inch by 8 inch sections of drywall to look inside the wall cavities 

for water damage or mold growth, and then we replaced the 

sections and sealed them with tape (Figure 12). We inspected 

the exterior of the building and the roof. We opened each of 

the air handling units to observe the condition of the internal 

components and the attached supply and return ducts. 

In several rooms that had previous water incursions, were adjacent 

to rooms that had previous water incursions, or had no previous 

(continued)
Page 10 Health Hazard Evaluation Report 2011-0096-3176

Assessment (continued)

incursions, we collected carpet dust samples into filter socks 

(Model X-Cell 100, Midwest Filtration Co., Cincinnati, OH) 

using a L’il HummerTM backpack vacuum (Pro-Team Inc, Boise, 

ID) from a 1 square meter area of the carpet for five minutes.

We sealed the dust samples in plastic bags and transported them 

on ice to the NIOSH laboratory. At the NIOSH laboratory, we 

removed hair, fluff, and other large objects from the sample. We 

emptied each dust sample into a 15 milliliter pyrogen-free conical 

tube and homogenized it by rotation on a 360-degree rotary arm 

shaker at 65 revolutions per minute for 2 hours. We sent a 100 

milligram fraction of each dust sample on ice to an environmental 

microbiology laboratory accredited by the American Industrial 

Hygiene Association (EMLab P&K, San Bruno, CA). We 

requested analysis of the dust samples for culturable fungi with full 

speciation, Gram-positive bacteria, Gram-negative bacteria, and 

actinomycetes.

We collected several material samples (bulk cutout, tweezed, or 

tape-lifted) from the inside insulated walls of two HVAC air supply 

ducts with suspected fungal contamination. We sent the samples 

in plastic bags on ice to the NIOSH laboratory. We asked for 

qualitative microscopic examination of the cutout, tweezed, and 

tape-lifted samples.

As we visited rooms, we asked the occupants about any IEQ 

concerns they may have had in the building.

Brief summary of prior consultant reports

March 2008

A March 2008 consultant report noted that the southwest (SW) 

back door at Hall 5 had no weather stripping, the nearby indoor 

carpet was damp, and the adjacent ground outside needed to be 

re-graded below slab level; a maintenance person placed weather 

stripping on the door frame before the end of the consultant’s 

inspection visit. Two ceiling tiles had small water stains. The 

report also noted low-efficiency filters in the rooftop AHUs. Realtime measurements collected one day throughout the building 

for temperature ranged from 63 degrees Fahrenheit (oF) to 71oF 

and for relative humidity (RH) from 33% to 48%; some of the 

temperatures being below the American Society of Heating, 

Results

Methods (continued)
Health Hazard Evaluation Report 2011-0096-3176 Page 11

Results (continued)

Refrigerating, and Air-conditioning Engineers (ASHRAE) 

recommended acceptability range for comfort. The consultant also 

data-logged temperature and RH levels over seven days and found 

that during most of the occupied periods they were acceptable. 

However, he noted that during some unoccupied morning periods, 

many interior spaces had RH measurements above the acceptability 

range upper limit of 60%. He also noticed vacuum cleaners did 

not use high-efficiency particulate air (HEPA) filters.

July 2009

A consultant conducted an investigation into the source of 

odors noticed mainly near the Room 34 reception area and Hall 

5. Outdoor air dampers on AHU-2, AHU-3, and AHU-5 were 

found to be closed. He noted ponding of water on a deteriorated 

section of roof material near a drain used for AHU-1 and AHU-2 

condensate drainage, and he observed a plant growing in the roof 

material. He reported that the roof was likely breached, based 

on water staining observed on the underside of the roof assembly 

near the drain for AHU-1 and AHU-2. Finding no indoor odor 

sources, the consultant suspected outdoor sources. 

June 2010

A consultant in June 2010 noticed no odors during his 

investigation. He reported moisture in the drywall at the bottom 

right corner of the window in Room 19 and recommended 

removal of a one foot section of the damaged window sill. He 

also noted water stains on the interior side of the roof assembly 

without ceiling tile staining. Low-efficiency filters were in some 

of the air handlers. Indoor RH measurements were 58%–61%. 

Concentrations of fungal spores found in indoor air were equal 

to or lower than outdoors. The consultant also reported visible 

mold growth (confirmed by microscopic analysis) in some of the 

air handlers, as well as some with insulation that was wet to the 

touch. Surface samples taken from ducts at the AHUs identified 

a large quantity of mold spores, hyphae, and black opaque 

particulates. He also found similar black opaque particulates on 

some horizontal surfaces inside the building and noted they were 

not consistent with typical indoor dust but probably came from 

outside, and they may have been contributing to the odor and 

symptoms described by the employees. 

October 2010

A consultant using a moisture meter reported no current moisture 

on tested materials in the building. He found water stains on 
Page 12 Health Hazard Evaluation Report 2011-0096-3176

Results (continued)

a Hall 5 interior wall (shared with Room 3) from a reported 

roof leak. He also reported visible water damage (paint peeling) 

above the baseboard close to the exit door on the Hall 11 west 

wall shared with Room 10. He performed wall cavity spore trap 

sampling in the Hall 11 water-damaged wall (shared with Room 

10) and in the exterior walls of Hall 5 and Room 6. In Hall 11, he 

found Aspergillus/Pencillium-like, Basidiospores, Cladosporium, and

Stachybotrys spores. He was unable to evaluate the east wall (shared 

with office 12) because of furniture along that wall. In the Room 6 

wall, the consultant found hyphal fragments, while the wall cavity 

sampling was negative in Hall 5. He recommended removal of the 

damaged section of the west wall (shared with Room 10) in Hall 

11 for inspection and repair. He also reported that the adjacent 

exterior door needed to be properly sealed. 

October-November 2010 (picture documentation)

In October, the building manager inspected the wall between Hall 

5 and Room 3. We were told by building occupants that a plugged 

AHU-1 condensate drain caused water to leak into the wall. The 

building manager replaced the baseboard in room 3 along the wall 

shared with Hall 5, and suspect mold was found (Figure 13). The 

damaged section of the drywall was removed (Figure 14), and the 

baseboard was replaced. In November, a large section hole was cut 

near the base of the Hall 5 wall shared with Room 3. No visible 

mold was found (Figures 15-18).

April 2011

During an Occupational Safety and Health Administration 

(OSHA) inspection on April 4, 2011, the inspector measured 

8-hour time-weighted average H2

S concentrations of 0.26, 0.95, 

and 0.33 parts per million (ppm), respectively, outside, and inside 

on personal samplers in Room 6 and in a cubicle across the hall 

from Room 3. Two other samples from Rooms 12 and 25 did not 

have any H2

S detected.

June 2011

An engineering consultant evaluated the building in May 2011 

to determine if it contained Chinese drywall. Based on visual 

observations of copper throughout the building and laboratory 

testing of drywall samples, they concluded there was no Chinese 

drywall in the building. 
Health Hazard Evaluation Report 2011-0096-3176 Page 13

Results (continued) NIOSH June 2011 site visit

Walkthrough evaluation 

During our walk-through of the building on June 22, the average 

inside temperature around 3:00 p.m. was 72°F, and the RH 

was 56%, while it was 88°F with an RH of 65% outside (Table 1). 

An average of 642 ppm CO2 was found inside, while it was 416 

ppm outside. A few trace measurements of CO were obtained 

in some rooms on the northwest side of the building; CO was 

not detected elsewhere. H2

S was not detected anywhere, inside 

or outside, including on the roof directly above sewer vents. The 

vapor analyzer measured an average of 0.1 ppm VOCs inside and 

0.2 ppm outside with its PID. Simultaneously, its FID measured 

an average of 1.5 ppm inside and 2.0 ppm outside. We smelled 

perfumes and colognes in multiple rooms.

We observed stained ceiling tiles in Room 23 and the adjoining 

hallway (both at the shared wall) and Rooms 28, 32, and 37. 

Investigation of the sources indicated that the stains in Room 23 

(Figures 19 and 20) and the adjoining hall were likely associated 

with the penetration area of an AHU-5 duct through the roof. The 

Room 37 stain was under a roof drain penetration (Figures 21 and 

22). A small nail-sized hole in the metal roof panel was located 

directly above the stained tile in Room 28, and the stain in Room 

32 was under a roof lap joint. 

In Room 3, on the wall shared with Hall 5, there was a raised area 

of the cloth wall paper from the ceiling down that was likely from 

the water leak that had previously occurred (Figure 23). In Room 

19, we observed water stains and blistering paint on the window 

sill (Figures 24 and 25). By the middle exterior door in Hall 11, we 

observed vertical water drip marks on the bottom half of the wall 

shared with Room 10 (Figure 26) that may have come from rain 

water falling from clothes and/or umbrellas as people enter.

In the ceiling plenum, we saw the cement-like roof insulation 

material, noted in previous reports that appeared to have oozed out 

from some roof lap joints during construction (Figures 27 and 28). 

Some of the roof lap joints had rusty stains, but none appeared to 

be wet (Figures 29 and 30). The HVAC flexible ducts appeared to 

be tightly fitted to main trunk lines and supply and return grilles; 

however, some of the flexible ducts probably had reduced air flow 

from being crimped by wire hangers (Figure 10). A coating of 

fine dust was seen on most of the trusses, ducts, and pipes in the 
Page 14 Health Hazard Evaluation Report 2011-0096-3176

Results (continued)

plenum (Figures 5, 8, 9, 10, 27, 29, and 30). Because it was not 

also seen on the ceiling supports and tiles, and the HVAC system is 

fully ducted, it was likely construction dust. 

We found the men’s bathroom to be neutrally pressurized in 

relation to the hallway. The women’s bathroom exhaust fan was 

able to keep it correctly negatively pressurized, thus preventing 

odors from escaping from the room. 

In Room 6, we observed a portable HEPA air cleaner unit. Room 

28 and the bathrooms had portable ultraviolet air cleaners.

We observed three custodial staff vacuuming carpets after business 

hours. Two vacuums had HEPA filters, and one did not.

We noted ill-fitting weather stripping around both back doors 

(Figures 31 and 32). Canvas awnings hung above each door, to the 

width of the door at Hall 5 (Figure 33a) and to the extent of the 

adjoining windows at the door at Hall 11 (Figure 34). Building 

occupants reported that the canvas awnings had been installed 

within the prior year.

On the roof, we observed no puddling of water from the rainfall 

just prior to our roof inspection, and the roofing material appeared 

to be in good condition. We found over-sized high-efficiency filters 

(Figure 35) in AHU-1, AHU-2, AHU-3, and AHU-5, causing gaps 

which allowed air to bypass the filters. In AHU-4, condensate 

water from the coils was found in the filter housing base and 

dripping into the outside air and return air mixing plenum rather 

than draining correctly to the drain (Figure 36). The bottom of 

the filter was wet. We smelled a musty odor and observed dust 

accumulation and suspect mold growth in AHU-1 (Figure 37) and 

AHU-4 (Figures 38 and 39a) supply ducts immediately after the 

fans. Other supply ducts and all return ducts viewed inside the 

AHUs had only minimal dust accumulation (Figure 39b). We 

observed dusty cooling coils (Figures 40 and 41), build-up in drain 

pans, and rusty areas in AHUs (Figures 42-44).

Building occupants reported episodes of water intrusion that 

resulted in wet carpet. They reported a history of frequent water 

leaks at the middle back door (Hall 11) and SW back door (Hall 

5) which improved after awnings were installed above the doors 

(Figures 33a and 34). They also reported that water had wet the 

carpet in the storage room (by Room 25) from a leak behind the 
Health Hazard Evaluation Report 2011-0096-3176 Page 15

Results (continued)

back wall of the storage room, and when the water leaked from 

AHU-1, the carpet near the wall shared by Hall 5 and Room 3 

became wet. The wet carpet in all the above instances was reported 

to have been left to air dry, with no aggressive drying.

We spoke with all the occupants of the accounting office and the 

majority reported building-related symptoms. Many reported one 

or more mucous membrane type symptoms including dry, itchy, 

or burning eyes; nasal dryness; dry throat; hoarseness; sneezing; or 

sinus problems. Others reported symptoms including coughing, 

fatigue, and rashes. A number of occupants reported frequently 

smelling odors described in various ways, including burning rubber 

smell, mildew smell, moldy smell, musty smell, wet-dog smell, 

sewage smell, sulfur smell, and rotten egg smell.

Wall cavity exploration

We did not find evidence of moisture, water damage, mold 

growth, or odor in any of the wall cavities evaluated. We, and the 

consultants in 2010, were unable to check inside the east wall in 

Hall 11 due to large shelving units on either side of the wall. We 

were also unable to evaluate the wall in Room 6 shared with Hall 5 

because of large file cabinets on both sides of the wall.

Carpet dust samples

Table 2 summarizes numbers and species of fungi and bacteria 

cultured from the carpet dust samples. Total fungi ranged from 

12,000 colony forming units per gram (cfu/g) in Room 2 to 

2,500,000 cfu/g by the SW back door (Hall 5). Total bacteria 

ranged from 25,000 cfu/g in Room 31 to 100,000,000 cfu/g by 

the SW back door. Bacillus, a Gram-positive bacteria, was highest 

by the SW back door in Hall 5 and the middle back door in Hall 

11. Thermophilic actinomycetes were detected in Halls 5 and 11, 

Rooms 2, 6, 29, and 31, and in the storage area by Room 25. 

HVAC samples

Cladosporium was cultured on both bulk cutout samples (Table 

3) taken from supply ducts above the ceiling in Room 3 (HVAC1) and the hallway near Room 12 (HVAC-4). The microscopic 

examination report (Table 4) indicated mold growth (indicated by 

hyphae) on those samples, as well as samples obtained from the 

same supply ducts at the rooftop AHUs.

 
Page 16 Health Hazard Evaluation Report 2011-0096-3176

Results (continued) Closing meeting at end of site visit

During the closing meeting, we recommended the following:

1. Replace fiberglass ducts for HVAC systems 1 and 4.

2. Replace weather stripping on Hall 5 and Hall 11 back doors. 

3. Increase the air flow in the men’s bathroom to put the 

bathroom under negative pressure in relation to the hallway. 

4. Evaluate the window in Room 19 for water leaks and fix any 

leaks. 

5. Evaluate source of leaks for the stained ceiling tiles.

6. Repair water leaks to prevent further water entry into the 

building. 

7. Remove or clean mold and moisture-damaged materials with 

appropriate containment to minimize exposure of building 

occupants.

8. During and after heavy rains, walk through the building to 

check for water incursion. 

9. Remove filtration/sanitizer devices in the bathrooms.

10.Implement a fragrance-free policy.

Update since Site Visit

Below is a brief summary of follow-up after our site visit in June 

2011.

July 2011

We shared the carpet dust and bulk material sampling results with 

the stakeholders. We recommended that the carpet be replaced 

with hard floors in Halls 5 and 11 partly because these are high 

traffic areas. In the other rooms, we recommended that the carpet 

be replaced with new carpet or hard floors. We suggested for 

rooms that were not tested that carpet dust sampling be performed, 

or the carpet be replaced similarly with the other rooms. We 

also suggested that concrete slab testing for moisture content 

would help in the selection of appropriate flooring. If new carpet 

would be installed, we recommended low VOC emitting carpet 

and adhesives be used. We recommended that carpet biocides 

not be used but that carpets be routinely HEPA vacuumed. We 

recommended that the non-HEPA vacuum that we observed 

during our visit be removed from the building and that the HEPAvacuums be properly maintained. We also recommended track-off 
Health Hazard Evaluation Report 2011-0096-3176 Page 17

Results (continued)

floor mats at all entries.

August 2011

We had a teleconference with industrial hygiene consultants hired 

by the building owner/management company; we reviewed our 

findings and recommendations and provided our carpet sampling 

protocol. In a letter from the building management company, 

dated August 8, 2011, it was reported that the window leak in 

Room 19 was repaired.

We provided our written interim findings and recommendations 

to the stakeholders. We recommended the following:

HVAC

1. Ensure proper maintenance of HVAC units.

2. Replace incorrectly sized HVAC filters. 

3. Develop a regular maintenance schedule.

4. Replace fiberglass ductwork for AHU-1 and AHU-4, 

preferably with metal ductwork with external insulation.

5. Replace or test fiberglass ducts for AHU-2, AHU-3, and 

AHU-5 for mold contamination.

6. Consult with ventilation engineers.

Carpet

1. Install track-off floor mats at exterior doors.

2. Routinely vacuum carpet with HEPA vacuum. 

3. Conduct additional slab moisture testing (e.g., perimeter 

of slab, Hall 5, Hall 11, Room 6, Room 12) to determine if 

there are any concrete slab moisture issues and to help in 

selecting appropriate flooring. 

4. Replace contaminated carpet (under conditions of 

containment and isolation) by exterior doorways (Hall 5 and 

Hall 11) with hard floors. 

5. Replace carpet (under conditions of containment and 

isolation) in the other areas sampled (areas 2, 6, 11, 12, 

storage room by room 25, 29, 31) with new carpet or hard 

floors taking into account slab moisture results.

6. Replace carpet in other rooms not sampled by NIOSH, or 

conduct carpet sampling in these rooms.

7. HEPA vacuum upholstered furniture.
Page 18 Health Hazard Evaluation Report 2011-0096-3176

Results (continued)

We had been informed by an the industrial hygiene consultant 

that the building owner planned to replace the carpet with hard 

floors by the middle back door (Hall 11) and SW back door 

(Hall 5). In the other areas, the industrial hygiene consultant 

informed us that the owner planned to clean the carpets and 

then resample the carpets. We recommended against a water 

cleaning method because water-loving fungi/yeast and bacteria 

were present in the carpet. If the cleaning method would involve 

water such as hot water extraction, we noted that drying would be 

very important and would likely require large fans and possibly 

running the ventilation system during the night hours to ensure 

continuous airflow. Additionally, the building occupants would 

need advance notice so that they could box up their belongings 

before the cleaning. Also furniture would need to be removed 

from the rooms before the cleaning. We did not recommend the 

use of carpet biocides as a routine practice. However, if biocides 

were used during the cleaning process, we recommended that the 

manufacturer’s recommendations for dilution, application, and 

worker protection (skin and respiratory protection) be followed.

We also noted that with sufficient access to water, microorganisms 

in carpet can proliferate so it would be important that the sources 

of moisture be remediated to prevent recontamination of new or 

cleaned carpet. If the carpet continued to be contaminated after 

cleaning, we recommended it be replaced.

Roof

1. Check for any roof leaks during and after heavy rains. This 

would include removing ceiling tiles to check the underside 

of the roof. 

2. Repair any roof leaks found.

Ceiling 

1. Determine water source for ceiling stains and repair any 

defects leading to water intrusion or leaks.

2. Replace stained ceiling tiles.

Wall

1. Remove a section of the west wall (shared with Room 10) by 

the middle back door (Hall 11) to inspect for water damage 

or mold growth. We recommended removal of a section 

from the exterior door frame out at least 5 linear feet and 

at least 2 feet up from the floor. We recommended taking 

pictures of the findings, and if there was water damage or 

mold growth, remove the affected areas and repair the wall 

(using proper containment and isolation methods).
Health Hazard Evaluation Report 2011-0096-3176 Page 19

Results (continued)

2. In Room 12, remove a section of the west wall (shared with 

Hall 11) to inspect for water damage or mold growth. We 

recommended removal of a section from the back (south) 

wall out at least 5 linear feet and at least 2 feet up from 

the floor and a similarly-sized section of the back wall 

immediately adjacent to the west wall (shared with Hall 11). 

We again recommended taking pictures of the findings, 

and if there was water damage or mold growth, remove the 

affected areas and repair the wall (using proper containment 

and isolation methods).

3. In Room 6, remove a section of the west wall (shared with 

area 5) to inspect for water damage or mold growth. We 

recommended removal of a section from the back (south) 

wall out at least 5 linear feet and at least 2 feet up from 

the floor and a similarly-sized section of the back wall 

immediately adjacent to the west wall (shared with Hall 

5). As noted above we recommended taking pictures of 

the finding, and if there was water damage or mold growth, 

remove the affected areas and repair the wall (using proper 

containment and isolation methods).

Other

1. Replace weather stripping around SW back door and 

middle back door. 

2. Fix exhaust fan in men’s bathroom so it was under negative 

pressure in relation to the corridor. 

3. Determine the source of the water stain on the window sill 

in Room 19 and repair.

4. Remove filtration/sanitizer devices in bathrooms.

5. Implement a fragrance-free policy. 

6. Walkthrough the building during and after heavy rains to 

check for leaks. Keep records of damp areas and repairs. 

7. During remediation, use proper isolation and containment 

methods to minimize exposures to remediation workers, 

building occupants, and unaffected sections of the building. 

8. Communicate remediation plans and timeline with the 

building occupants in advance.

Also in August 2011, an HVAC contractor for the building owner 

placed temperature and RH data-logging monitors in several 

locations for five days. In the front reception area, Cubicle 16, 
Page 20 Health Hazard Evaluation Report 2011-0096-3176

Results (continued)

and Room 29, the temperature ranged from approximately 70oF 

to 75o

F, and the RH ranged from approximately 48% to 56%. 

In the work area across from Room 2, the temperature ranged 

from approximately 70o

F to 74oF, and the RH ranged from 

approximately 48% to 62%. In Room 2, the temperature ranged 

from approximately 66o

F to 74oF, and the RH ranged from 54% to 

64%. 

Later in August 2011, an industrial hygiene consultant took room 

air temperature and RH measurements at the end of concrete slab 

moisture testing in Rooms 2, 21, 27, and 29. At around 6:00 p.m., 

the temperatures in the rooms ranged from 68.9oF to 73.5oF, and 

the RH ranged from 44% to 53%. The reported relative humidity 

of the concrete ranged from 48.5% to 59%. 

The industrial hygiene consultant in a letter dated August 15, 

2011 reported the exhaust fan air flow for the men’s bathroom was 

increased. Carpet was removed, and replaced with ceramic tile in 

Room 6, Hall 5, and Hall 11.

September 2011

We provided requested information to building occupants about 

how to conduct wall cavity inspections. 

The property management company had replaced the weather 

stripping around the exterior doors. At the Hall 5 door, the asphalt 

landing was replaced with a concrete landing and a wider awning 

was installed (Figure 33b). The southwest wall (back wall with 

two exterior doors) was waterproofed and a new French drain was 

installed along the wall. Additionally, some plants that had an 

offensive odor were removed and the foundation was re-graded for 

better drainage.

October - November 2011

An industrial hygiene consultant letter dated October 10, 2011 

reported remediation activities at the office building up to that 

date. The document reported that during their wall cavity 

exploration, suspect visible mold was found in Rooms 6 and 10. 

In Room 6, water stains, rust on the floor plates, and leaves were 

observed in the back wall cavity; suspect mold was observed on 

an approximately one foot long section of the bottom edge of 

the drywall. The document stated the drywall was replaced. In 

Room 10, suspect mold was reported on drywall in the southeast 

corner (back left corner as enter the room). This drywall was 
Health Hazard Evaluation Report 2011-0096-3176 Page 21

Results (continued)

also removed and replaced. The letter indicated the wall cavities 

were clean, and no visible mold or water stains were found in the 

Room 6 northwest wall shared with Hall 5, Room 10 southwest 

wall (exterior back wall), Room 12 northwest wall shared with Hall 

11, and Room 12 southwest wall (exterior back wall). The letter 

also mentioned that a new French drain had been installed along 

the southwest wall (rear) and that the wall had been waterproofed 

(“stripped down to block, sealed, and coated with new waterproof 

stucco”). The industrial hygiene consultant emailed NIOSH 

multiple pictures of the wall cavity exploration.

We recommended they evaluate the two wall cavities in Room 4, 

specifically, in the back wall and the wall shared with Hall 5. In a 

letter dated December 2, 2001, the industrial hygiene consultant 

felt that it was not necessary and noted that the backside of Room 

4’s wall shared with Hall 5 was clean, and there was no evidence 

of water or mold damage. The letter reported that the building 

management company had removed and replaced approximately 

175 square feet of drywall; less than one square foot had visible 

mold. We were also informed by the industrial hygiene consultant 

during a teleconference that no water damage was noted on the 

exterior of the southwest wall.

On October 24, 2011, the industrial hygiene consultant collected 

dust in 13 rooms (1, 2, 4, 10, 12, 17, 20, 27, 29, 31, 34, 35, and 

copy room) to test for allergens. The collection method was not 

described, but we assume it was settled dust (not airborne dust). 

The samples were analyzed using ELISA methodology for cat (Fel 

d1), dog (Can fl), cockroach (Bla g1), and dust mite (Der f1 and 

Der p1) allergens. The samples were below the limit of detection 

for dust mite (<0.39 microgram (μg)/gram) and cockroach (<1.6 

units/gram) allergens. All 13 rooms had detectable levels of cat 

allergen that ranged from 0.35 μg/gram +/- 0.036 in Room 2 

to 4.23 μg/gram +\-0.44 in Room 12. Six rooms were below 1 

μg /gram; three rooms were between 1-2 μg /gram, and three 

were between 2-3 μg /gram. Ten rooms had detectable levels of 

dog allergen that ranged from 0.62 μg/gram +/-0.13 in Room 

17 to greater than 25 μg/gram in Room 20. Nine of the 10 

measurements from rooms with dog allergen were ≤ 2.5 μg /gram. 

Rooms 1, 2, and 10 had no detectable levels of dog allergen. 

We received a carpet cleaning protocol dated October 28, 2011 

from the industrial hygiene consultant. It included the optional 

use of tannic acid or borate solution. If carpet cleaning was 
Page 22 Health Hazard Evaluation Report 2011-0096-3176

Results (continued)

attempted, we recommended dry steam cleaning which uses 

a high temperature, low moisture vapor, usually below 6% of 

water content. During our carpet dust sampling for bacteria and 

fungi in June 2011, we found water-loving fungi/yeast and Gramnegative and Gram-positive bacteria. We thought that adding 

water to the carpet by using a “wet” method was not a good idea. 

We did not recommend using borate or tannic acid during the 

cleaning process. Before the carpet cleaning, we recommended 

HEPA-vacuuming each room before and after removal of office 

contents to help reduce the suspension of carpet dust and limit 

contamination. We also recommended sufficient drying of 

the carpet after the cleaning process and HEPA-vacuuming the 

rooms before replacing the office contents. Additionally, we 

recommended carpet dust sampling after the carpet cleaning to 

determine if the cleaning had been successful. The results could be 

compared with the NIOSH carpet dust sample results collected in 

June 2011.

A letter dated October 27, 2011 from the engineering consultant 

recommended adding exhaust fans in the copy rooms, enhanced 

housekeeping, storing boxes off the floor, daily HEPA-vacuuming, 

using perforated floor mats, and replacement of AHU-1 and 

AHU-4. We agreed with these recommendations. We also 

recommended monitoring the concrete slab in a few more areas to 

look for moisture intrusion rates. 

We thought the planned ventilation renovations seemed reasonable 

including the replacement of air handling units AHU-1 and 

AHU-4. We also thought the inclusion of a dedicated outdoor air 

system (DOAS), mentioned in a report dated October 27, would 

alleviate the outside air cooling load (especially the latent heat that 

is responsible for condensation and possibly microbial growth) 

from the other AHUs. That system, if designed properly, should 

alleviate most (if not all) condensation on the coils in the other 

AHUs and allow them to provide better temperature/humidity 

control in the occupied spaces. Also, a properly designed DOAS 

would ensure ASHRAE-recommended levels of fresh, outside air 

to the building occupants at all times throughout the year without 

significantly affecting the operating parameters of the other AHUs.

A letter from the engineering consultant dated November 10, 2011 

did not mention the DOAS in the context of the replacement of 

AHU-1 and AHU-4. We thought the recommended replacement of 

AHU-1 with a smaller 4 ton unit would allow additional runtime 

as stated in the letter. We also liked the idea of a 2-stage unit for 

AHU-4 if the DOAS was not added. In a letter dated November 1, 
Health Hazard Evaluation Report 2011-0096-3176 Page 23

Results (continued)

2011 from the engineering consultant, the engineer recommended 

removal of AHU-1 main ductwork through the first two sections 

of horizontal ductwork off the unit and that remaining ductwork 

would be removed until visually found to be clean as verified 

by the engineer or his representative. For AHU-4, the engineer 

consultant also recommended that the main ductwork be removed 

and replaced throughout the main duct run. 

In November 2011, AHU-4 was changed to a 2-stage unit to 

increase the time that active cooling was occurring and to increase 

the ventilation that was brought into the area served by the unit. 

AHU-1 was downsized to better match the load of the area served. 

Some of the fiberglass ductwork was also replaced. 

December 2011

We provided the building occupants with a requested carpet 

removal protocol for the accounting office.

We had a teleconference with industrial hygiene and engineering 

consultants hired by the building owner/manager. There was a 

question about the condensate drainage for AHU-4. This was 

evaluated about a week later by an employee for the engineering 

company. The condensate drain was reported to drain properly. 

The AHU-4 was also reported to be properly trapped, and the 

inside of the unit and ductwork connected to the unit were 

reported to be clean and dry. The ceiling tiles below the unit were 

reported to be clean and unstained.

February/March 2012

A building occupant reported finding two to three silver dollar size 

spots resembling mold on the carpet under a chair mat in Room 

13. 

In late February or early March, the carpet in the accounting office 

was steam cleaned. 

November 2012

A building occupant informed us that some building occupants 

continued to have symptoms, and the accounting company would 

be relocating to another building.

December 2012

The accounting company relocated to another building. The 

remaining carpet had not been tested (carpet dust) or replaced 

prior to moving.
Page 24 Health Hazard Evaluation Report 2011-0096-3176

Occupants of this building had a several-year history of buildingrelated symptoms, which was reflected in recurrent complaints 

to the building management company and several consultant 

reports from 2008 until the time of the NIOSH survey in June 

2011. Workers reported water damage reflected in stained ceilings 

and walls. Consultants had findings reflecting water damage, also 

including stained ceiling tiles as well as visible mold and wall cavity 

sampling identifying Stachybotrys, a water-loving fungus [Hung et al. 

2005] that is not normally present on building materials [Prezant 

et al. 2008] and reflects wet indoor conditions. Nonetheless, 

confusion about the nature and source of odors resulted in 

exploring other explanations such as hydrogen sulfide and 

Chinese drywall, rather than remediating dampness or accepting 

that indoor dampness was an adequate cause for occupants’ 

indoor environmental quality complaints. There is growing 

epidemiological evidence of associations between respiratory 

health effects and microbial contaminants derived from mold and 

bacteria, allergens from dust mites and cockroaches, and chemical 

agents released from wetted building materials and furnishings 

[IOM 2004; WHO 2009].

Symptoms

The occupants reported symptoms consistent with damp indoor 

environments. In 2004, the Institute of Medicine (IOM) of the 

National Academies published an extensive review of past scientific 

studies on the health effects of damp buildings [IOM 2004]. In 

2009, the World Health Organization (WHO) published guidelines 

for dampness and mold based on an updated review [WHO 2009]. 

The WHO report points out that (1) clinical evidence is sufficient

to conclude that exposure to mold and other dampness-related 

microbial agents in the indoor environment increases the risk of 

hypersensitivity pneumonitis, chronic rhinosinusitis, and allergic 

fungal sinusitis; (2) epidemiological evidence is sufficient to conclude 

that occupants of damp or moldy buildings are at increased 

risk of respiratory symptoms (specifically upper respiratory tract 

symptoms, cough, wheeze, and shortness of breath), respiratory 

infections, asthma development, current asthma, and asthma 

exacerbation; and (3) epidemiological evidence suggests that occupants 

of damp or moldy buildings are also at increased risk of bronchitis 

and allergic rhinitis. Importantly, the WHO guidelines note that 

although allergy and atopy (genetic tendency to develop allergic 

diseases such as atopic dermatitis, hay fever, and asthma) increases 

susceptibility to dampness-related health effects, such health effects 

Discussion
Health Hazard Evaluation Report 2011-0096-3176 Page 25

Discussion (continued)

are also found in non-atopic building occupants. Additional 

evidence from a more recent epidemiologic review reported that 

bronchitis, shortness of breath, and eczema should be added to the 

list of health outcomes with sufficient evidence of an association 

to dampness and dampness-related agents [Mendell et al. 2011]. 

Vocal-cord dysfunction has also been reported in workers in waterdamaged buildings [Cummings et al. 2013]. 

Microbial contamination – carpet and ventilation supply 

ducts

Bacteria, fungi, actinomycetes, and non-tuberculous mycobacteria 

have been associated with damp indoor environments. In this 

building, bacteria, fungi, and actinomycetes were identified in the 

carpet dust samples and in bulk material collected from inside the 

ventilation insulation board supply ducts. The carpet dust samples 

we collected had Gram-negative bacteria, which suggest indoor 

sources of dampness [Burge 1994], and many fungi that grow in 

environments with high or moderate water activity (e.g., yeasts, 

Phoma spp, Alternaria alternata, Aspergus niger, Aspergillus ochraceus, 

Cladosporium cladosporioides, Penicillium brevicompactum) [Hung et 

al. 2005]. The spectrum of fungal species identified indicate that 

the carpet likely experienced chronic wet conditions in the past 

or alternating cycles of wet and dry conditions. Currently, there 

are no standards for what level or what species of molds constitute 

a health risk. For example, all molds have the potential to be 

allergenic, but little knowledge exits on the antigens or allergens 

found in the vast majority of molds. An OSHA technical manual 

[1999] reports contamination indicators of 1,000,000 fungi per 

gram of dust or material; however, this is not based on health 

risk. Dr. Burge, EMLab P&K’s Director of Aerobiology, also 

reported unusual levels of microorganisms in dust samples [Burge 

2010]. However, there are no accepted quantitation levels for 

health effects for microorganisms in carpet dust.

Thermophilic actinomycetes were detected in all the carpet and 

the bulk material collected from inside the ventilation insulation 

board supply ducts, which likely resulted in the circulation of the 

microbes throughout the building. Thermophilic actinomycetes 

are bacteria that thrive at higher temperatures and cause 

hypersensitivity pneumonitis (also referred to as extrinsic allergic 

alveolitis) [Eduard 2009]. Hypersensitivity pneumonitis is an 

immunologically-mediated, granulomatous lung disease caused 

by repeated inhalation and sensitization to various organic agents 
Page 26 Health Hazard Evaluation Report 2011-0096-3176

Discussion (continued)

including microbial agents [Girard et al. 2004]. 

In this building, the carpet was replaced with hard flooring in one 

office and at the door entries. The rest of the carpet was steam 

cleaned. The steam cleaned carpet was not re-sampled (carpet dust) 

to determine if the cleaning had effectively removed the microbial 

contamination. If the carpet is still contaminated with microbes, 

this may have accounted for some of the continued symptoms in 

building occupants. 

The contaminated fiberglass ducts were reported to have been 

replaced with fiberglass ducts. Because fiberglass ducts can have 

a rough surface, they often make an excellent trap for dust. A 

lot of dust is organic dust, which will often grow mold and 

bacteria with moisture. Fiberglass insulation that has mold 

growth must be replaced because it cannot be cleaned. Smooth 

metal interior ductwork is often a better alternative. It will be 

important to properly maintain the HVAC units to prevent future 

contamination. 

We do not recommend the use of biocides on carpet or in the 

HVAC system. The growth of mold and bacteria in indoor 

environments is due to excess moisture; thus, application of 

biocide as a protective action is unnecessary if moisture is properly 

controlled. Biocides should not be applied in an occupied 

building or in an operating HVAC system [Sesline et al. 1994]. 

Any biocide use on carpet or in HVAC systems or ductwork, even 

EPA-approved biocides, should be minimized, carefully monitored 

in terms of occupant health and air quality, and guided by 

professional judgment [Prezant et al. 2008].

Indoor relative humidity and temperature

Controlling indoor relative humidity is also an important factor 

to prevent microbial growth in the ventilation ducts and carpet. 

During our visit, indoor relative humidity measurements were 

within normal range; however, some RH measurements were on 

the high end of normal. This was also observed in 2008 when a 

consultant recorded indoor relative humidity levels above 60%, 

mainly during unoccupied periods in the early morning hours, and 

in August 2011 when a consultant measured peak indoor humidity 

readings of 62% and 64%. In the United States, ASHRAE 

recommends that indoor RH be maintained at or below 65% 

[ANSI/ASHRAE 2010A]. The U.S. Environmental Protection 
Health Hazard Evaluation Report 2011-0096-3176 Page 27

Discussion (continued)

Agency (EPA) recommends maintaining indoor RH between 30%–

50% because excessive humidity can promote the excessive growth 

of microorganisms [EPA 2008]. During our evaluation, the HVAC 

systems were running during occupied hours and turned off at 

night. While turning the system off may seem more economic, it 

also increases demand on the system when it is turned back on to 

reach desired temperature set-points. It can also create issues with 

humidity and condensation if temperatures indoors become warm 

during the “off” periods. This is particularly true in areas with 

warmer climates such as Florida. 

Assuming slow air movement and 50% RH, the operative 

temperatures recommended by ASHRAE range from 68.5o

F–

76o

F in the winter, and from 75.5oF–80.5oF in the summer (see 

table below). The difference between the two is largely due to 

seasonal clothing selection [ANSI/ASHRAE 2010A]. During 

our summertime visit, the indoor temperature averaged 72o

F, a 

few degrees below the lower range recommended by ASHRAE. 

However, if building occupants feel comfortable at that 

temperature, then there is no real reason for concern as long as RH 

levels remain controlled.

Relative Humidity Winter Temperatures1 Summer Temperatures1

30%2 69.5–77.0 oF 75.5–81.5 oF

40% 69.0–76.5 oF 75.5–81.0 oF

50%3 68.5–76.0 oF 75.0–80.5 oF

1 Applies to occupants wearing typical summer and winter clothing, with a sedentary to 

light activity level. 

2 Humidity levels below 30% may cause irritated mucus membranes, dry eyes, and sinus 

discomfort. 3

 EPA recommends maintaining indoor RH below 60% and ideally in a range from 30%– 50% to prevent mold growth.

Ventilation 

During our visit, the office building had adequate ventilation 

during the day based on carbon dioxide (CO2

) levels. ASHRAE 

notes in an appendix to standard American National Standards 

Institute (ANSI)/ASHRAE 62.1-2010: Ventilation for Acceptable 

Indoor Air Quality 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, 
Page 28 Health Hazard Evaluation Report 2011-0096-3176

Discussion (continued)

2010B]. This would typically correspond to indoor concentrations 

below 1200 ppm since outdoor CO2 concentrations usually 

range between 375 to 500 ppm. Elevated CO2

 concentrations in 

a building suggest that other indoor contaminants may also be 

increased and that the amount of outdoor air introduced into 

the ventilated space to dilute those pollutants may need to be 

increased. 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 guidelines provide specific details on ventilation 

for acceptable indoor environmental quality. ANSI/ASHRAE 

Standard 62.1-2010: Ventilation for Acceptable Indoor Air Quality 

specifies “minimum ventilation rates and other measures intended 

to provide indoor air quality that is acceptable to human occupants 

and that minimize adverse health effects”[ANSI/ASHRAE 

2010B]. Generally, the standard recommends outdoor air supply 

rates to indoor occupied spaces that take into account peoplerelated sources as well as building-related sources. For office 

spaces, conference rooms, and reception areas, 2.5 liters per second 

per person (L/s•person) (5 cubic feet per minute [cfm] of outside 

air per person [cfm/person]) is recommended for people-related 

sources, and an additional 0.3 liters per second per square meter 

(L/s•m2

) (0.06 cfm per square foot [cfm/ft2]) of occupied space 

is recommended to account for building-related sources. For 

spaces where airborne contaminants and odors are prevalent, the 

standard offers minimum exhaust rates from the space. For copy 

and printing rooms, the standard recommends an exhaust rate of 

at least 2.5 L/s•m2

 (0.5 cfm/ft2) directly outdoors. The makeup 

air for this exhaust air can consist of any combination of outdoor 

air, recirculated air, or air transferred from adjacent spaces. When 

normal dilution ventilation does not reduce occupant exposures 

to emissions from office equipment to acceptable levels, some 

form of local exhaust ventilation must be considered to remove the 

contaminant from the source before it can be spread throughout 

the occupied space. However, little scientific research has been 

done to develop and/or test the performance of local exhaust 

systems for typical office equipment.

Portable Air Cleaners

We observed a portable HEPA air cleaner unit and ultraviolet air 

cleaners during our site visit. HEPA units are made to remove 

particles from the air, which could include some mists. Ultraviolet 
Health Hazard Evaluation Report 2011-0096-3176 Page 29

Discussion (continued)

air cleaners kills living organisms. Portable air cleaners should not 

be necessary if there is appropriate ventilation and no issues with 

indoor dampness. Portable air cleaners that produce ozone can 

cause adverse respiratory health effects and should be avoided [EPA 

2009 and 2013]. 

Cat and Dog Allergens 

In 2011, cat (Fel d 1) and/or dog (Can f 1) allergens were identified 

in dust samples collected by an industrial hygiene consultant at 

the accounting office. The consultant found cat allergen in more 

rooms than dog allergen which is common. Cat allergens are 

ubiquitous, being found in homes with and without cats and in 

many schools and office buildings; the levels of allergens in office 

buildings and schools are generally lower than residential exposures 

[Cox-Ganser et al. 2010]. Cat and dog allergens are transported 

on the clothing of people (such as employees and visitors) who 

have household pets to pet-free areas such as workplaces [Perfetti 

et al. 2004]. Multiple studies have shown dog and cat allergens 

on carpet and often much higher levels on upholstered chairs in 

public places and indoor workplaces [Custovic et al. 1996, 1998; 

Perfetti et al. 2004]. These passively transferred allergens can 

become airborne and cause respiratory symptoms in individuals 

allergic to cats or dogs. In general, the lower the level of allergen in 

the environment, the lower the risk of allergic symptoms. 

Fragrances

During our visit, we smelled perfumes and colognes in multiple 

rooms. No building occupants complained about the perfume or 

cologne scent. Several hundred different chemicals are used to 

make fragrances, many with little available health data. Fragranced 

products have been implicated in causing dermatologic problems 

[Buckley et al. 2002] and inducing or worsening respiratory 

problems [Bridges 2002] including asthma [Baldwin et al 1999; 

Kumar et al. 1995; Caress and Steinemann 2009] and vocal cord 

dysfunction [Hoy et al. 2010]. Fragranced products are reported 

to trigger symptoms in individualswith asthma [Baldwin et al 

1999; Kumar et al. 1995; Caress and Steinemann 2009], hay 

fever [Baldwin et al 1999], and migraines [Kelman 2004 and 

2007], even when the individuals are not “allergic” to fragrance 

ingredients. In one study, investigators collected data through 

telephone interviews from two geographically weighted, random 

samples in the continental U.S. in surveys during 2002-2003 

(1,057 participants) and 2005-2006 (1,058 participants). Results 
Page 30 Health Hazard Evaluation Report 2011-0096-3176

aggregated from both surveys found that 30.5% of the general 

population reported scented products irritating and 19% reported 

adverse health effects such as headaches and breathing problems 

[Caress and Steinemann 2009].

We recommended that the management at the accounting 

office implement a fragance-free policy. Many employers have 

established fragrance-free policies in their workplaces to protect 

their workers who are symptomatic when exposed to products 

that contain fragrances. These policies generally prohibit the 

use of the following types of scented products anywhere in their 

buildings: perfumes and colognes, deodorants, hairsprays, lotions 

and creams, potpourri, air fresheners, candles, scented soaps and 

cleaning chemicals, and any other fragrance-containing products. 

In addition, use of soaps and cleaning products by janitorial staff 

can be limited to products that are fragrance-free or emit only 

low levels of VOCs. Workers can also be encouraged to be as 

fragrance-free as possible upon arrival at the buildings, including 

not only the personal care products used on their skin, but also by 

avoiding use of scented detergents and fabric softeners on clothes 

worn to the building.

Health Outcomes Following Remediation

Numerous studies have documented health outcomes following 

remediation of water-damaged buildings. In some buildings, 

remediation has been followed by decreases in respiratory 

symptoms reported by occupants [Jarvis and Morey 2001; 

Haverinen-Shaughnessy et al. 2004; Meklin et al. 2005; Kercsmar 

et al. 2006; Lignell et al. 2007; Haverinen-Shaughnessy et al. 2008] 

and no new cases of respiratory illness [Jarvis and Morey 2001]. In 

other buildings, remediation has not resulted in improved health 

outcomes. Incomplete remediation is one possible explanation 

[Ebbehoj et al. 2002; Patovirta et al. 2004; Meklin et al. 2005; 

Haverinen-Shaughnessy et al. 2008; Iossifova 2011]. Yet there 

is also evidence that remediation may be effective in terms of 

preventing new illness, but not eliminating symptoms in previously 

affected occupants [Haverinen-Shaughnessy et al. 2004]. For some 

employees, an individualized management plan (such as assigning 

an affected employee to a different work location, perhaps at home 

or a remote site) is required, depending upon medical findings and 

recommendations of the individual’s physician.

Discussion (continued)
Health Hazard Evaluation Report 2011-0096-3176 Page 31

Conclusions

(continued) The building-related symptoms experienced by many employees in 

this building are consistent with diverse exposures found in damp 

indoor buildings. There was evidence for dampness in occupant 

observations, historical consultant reports, NIOSH findings of 

unusual high levels of microrganisms requiring damp indoor 

environments in carpet dust, HVAC contamination, and interior 

water stains on ceiling tiles and walls. Many appropriate steps were 

taken to correct moisture intrusion and ventilation problems after 

the NIOSH visit. We understand that these were insufficient to 

prevent ongoing symptoms in occupants of the building, who have 

moved to another location.

Recommendations Based on our findings, we recommend the actions listed below to 

create a more healthful workplace for future tenants.

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 efficiency.

1. Use track off floor mats at each door way.

2. Avoid the use of chair mats. If not feasible, use perforated 

floor mats.

3. As much as possible, keep papers and boxes off the floor. A 

non-cluttered room is easier to clean and HEPA vacuum. If 

feasible, an empty office could be converted into a storage 

area with shelves for boxes and filing cabinets for paper 

work. 

4. Carpets should be routinely HEPA vacuumed. Ensure the 

HEPA-vacuum is well-maintained, and the HEPA filter is 

changed according to the manufacturer’s recommendations. 

Avoid the use of carpet biocides. 

5. We recommend carpet dust sampling to determine if carpet 

cleaning has been successful. The results can be compared 
Page 32 Health Hazard Evaluation Report 2011-0096-3176

Recommendations

(continued) with the NIOSH carpet dust sample results collected in June 

2011. If there is not a significant decrease in microbes, the 

carpet may need to be removed. If the carpet is replaced, 

we recommend monitoring the concrete slab for moisture 

intrusion rates in additional places beyond the previous 

moisture concrete slab testing.

6. Do not rely upon air sampling for mold since air 

concentrations cannot be interpreted with respect to health 

risk. Observing or smelling mold is sufficient motivation 

for dampness remediation when occupants have buildingrelated symptoms.

7. Following the manufacturer’s recommended maintenance 

schedules for the HVAC system, including replacing air 

filters, checking drip pans, ensuring thermostats are in 

working order, and checking and cleaning ventilation system 

dampers to ensure proper functioning. 

8. Operate the ventilation system on a reduced setting (warmer 

during cooling months and cooler during heating months) 

during unoccupied hours instead of turning the system 

completely off.

9. Avoid using portable air cleaners that produce ozone, 

which can cause adverse respiratory effects. Information 

about ozone generators sold as air cleaners can be found on 

the U.S. EPA website at http://www.epa.gov/iaq/pubs/

ozonegen.html.

10. Continue to routinely assess the building for water intrusion 

and damage and high relative humidity and correct these 

upon discovery. During and after heavy rains, walk through 

the building and check for water incursion. When sources 

of moisture are identified, repairs should be made to 

prevent further water entry into the building. 

11. If there are continued health complaints by building 

occupants or musty or moldy odors, evaluate the area for 

hidden dampness and mold. An infrared camera can be 

used inside and outside the building after a heavy rain to 

look for hidden moisture and leaks. Also check for hidden 

sources under carpet (especially underneath windows or 

other areas with a history of leaking), above the ceiling, 

and in the walls (by cutting a hole in the wall and visually 

inspecting the area for odors, visible mold, and water 

damage). 
Health Hazard Evaluation Report 2011-0096-3176 Page 33

Recommendations

(continued) 12.Any future mold and moisture-damaged materials should be 

promptly removed or cleaned with appropriate containment 

to minimize exposure for remediation workers, building 

occupants, and unaffected sections of the building. Keep a 

record of when and where mold or water-damaged materials 

are discovered and what has been done to promptly fix the 

underlying problem leading to the water damage. 

13.Any building occupant who experiences worsening, 

persistent, or recurrent respiratory or other health symptoms 

that may be associated with being in the building should see 

his/her physician; the building occupant may need to be 

relocated to another site within the building or relocated to 

a different site out of the building.

14. Although there were no specific complaints about fragrance 

or colognes, consider implementing a fragrance-free policy.
Page 34 Health Hazard Evaluation Report 2011-0096-3176

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Health Hazard Evaluation Report 2011-0096-3176 Page 37 Tables Table 1. Air measurements obtained by NIOSH investigators on June 22, 2011, accounting office, Florida Carbon Dioxide Carbon Monoxide Hydrogen Sulfide Total VOCs* (ppm) Temperature Relative Humidity Location Time (ppm*) (ppm) (ppm) PID* FID* (oF) (%) Outside Front parking lot 14:34 416 0† 0† 0.2 2.0 88 65 Outside Roof (multiple sites) 8:15‡ --- --- 0 --- --- --- --- Room 1 Conference room 14:42 650 0.3 0 0.2 1.8 74 50 Room 2 Office 14:46 --- --- --- 0.2 1.6 --- --- Cubicles Near Room 2 14:45 655 0.2 0 0.2 1.6 74 54 Room 3 Office 14:47 618 0.2 0 0.1 1.5 72 55 Room 4 Office 14:52 680 0 0 0.1 1.5 72 57 Room 6 Office 14:54 684 0 0 0.1 1.4 72 55 Room 7 Office 14:57 --- --- --- 0.1 1.4 --- --- Room 9 Office 15:20 626 0 0 0.1 1.5 72 55 Room 12 Office 15:18 647 0 0 0.1 1.4 73 58 Room 15 Office 15:15 632 0 0 0.1 1.4 73 56 Room 16 Office 15:14 651 0 0 0.1 1.4 72 59 Room 18 Office 15:12 651 0 0 0.1 1.4 72 57 Room 20 Office 15:10 634 0 0 0.1 1.4 71 57 Room 25 Office 15:08 640 0 0 0.1 1.4 72 55 Room 28 Reception 15:06 646 0 0 --- --- 72 57 Room 29 Office 15:05 620 0 0 0.1 1.4 72 56 Room 30 Office 15:02 605 0 0 0.1 1.4 73 58 Room 31 Office 15:04 621 0 0 --- --- 73 61 Room 34 Reception 14:59 637 0 0 0.2 1.6 73 58 Room 36 Office 14:57 652 0 0 0.1 1.4 72 59 Room 38 Storage 15:24 --- --- --- 0.1 1.5 --- --- Average inside 642 0.04 0 0.1 1.5 72 56 Minimum inside 605 0 0 0.1 1.4 71 50 Maximum inside 684 0.3 0 0.2 1.8 74 61 * ppm = parts contaminant per million parts air; VOC = volatile organic compound; PID = photoionization detector; FID = flame ionization detector; --- (dashes) = not sampled †detection limit 0.1 ppm; ‡samples collected on June 23, 2011
Page 38 Health Hazard Evaluation Report 2011-0096-3176

Tables (continued)

Table 2. Microbial agents cultured* from carpet dust vacuum samples collected by NIOSH investigators on 

June 22, 2011, accounting office, Florida

Sample 

location

Fungi Bacteria

Identification cfu/g† Identification cfu/g†

Room 2 Alternaria alternata 1,200 Bacillus 440,000

Aspergillus niger 1,600 Gram negative rods 1,300,000

Aureobasidium pullulans 800 Gram positive cocci 40,000

Basidiomycetes 800 Total bacteria 1,800,000

Cladosporium cladosporioides 1,200

Curvularia lunata 400 Thermophilic actinomycetes 800

Epicoccum nigrum 2,000

Nonsporulating Fungi 800

Penicillium minioluteum 400

Penicillium sclerotiorum 400

Pithomyces chartarum 1,200

Yeasts 1,200

Total fungi 12,000

Hall 5

(by SW back 

door)

Aspergillus ochraceus 80,000 Bacillus 800,000

Aspergillus sydowii 80,000 Gram negative rods 99,000,000

Aspergillus ustus 1,800,000 Total bacteria 100,000,000

Basidiomycetes 80,000

Cladosporium cladosporioides 160,000 Thermophilic actinomycetes 2,800

Penicillium chrysogenum 320,000

Total fungi 2,500,000

Hall 5

(between 

Room 4 and

hallway)

Alternaria alternata 4,000 Bacillus 120,000

Aspergillus niger 4,000 Gram negative rods 4,600,000

Aspergillus ustus 56,000 Total bacteria 4,800,000

Fusarium species 12,000

Yeast 20,000 Thermophilic actinomycetes 1,600

 Total fungi 96,000

Room 6 Alternaria alternata 4,000 Bacillus 68,000

Aspergillus niger 24,000 Gram negative rods 160,000

Aspergillus ustus 8,000 Total bacteria 220,000

Basidiomycete 8,000

Chaetomium globosum 8,000 Thermophilic actinomycetes 1,600

Cladosporium cladosporioides 8,000

Curvularia lunata 8,000

Nonsporulating fungi 16,000

 Total fungi 84,000
Health Hazard Evaluation Report 2011-0096-3176 Page 39

Tables (continued)

Table 2 (continued). Microbial agents cultured* from carpet dust vacuum samples collected by NIOSH 

investigators on June 22, 2011, accounting office, Florida 

Sample 

location

Fungi Bacteria

Identification cfu/g† Identification cfu/g†

Hall 11

(by middle

back door)

Aspergillus ustus 20,000 Bacillus 800,000

Cladosporium cladosporioides 24,000 Gram negative rods 23,000,000

Nonsporulating fungi 20,000 Gram positive cocci 400,000

Paecilomyces marquandii 4,000 Total bacteria 24,000,000

Penicillium brevicompactum 4,000

Penicillium chrysogenum 4,000 Thermophilic actinomycetes 400

Phoma species 350,000

Total fungi 420,000

Room 12

Aspergillus caespitosus 4,000 Bacillus 40,000

Aspergillus flavus 8,000 Gram negative rods 2,800,000

Aspergillus niger 24,000 Gram negative cocci 1,200,000

Aspergillus ochraceus 8,000 Total bacteria 4,000,000

Cladosporium cladosporioides 4,000

Curvularia lunata 4,000 Thermophilic actinomycetes <400

Nonsporulating fungi 28,000

Yeast 8,000

 Total fungi 88,000

Storage area

(by Room

25)

Alternaria alternata 4,000 Bacillus 38,000

Aspergillus caespitosus 8,000 Gram negative rods 2,800

Aspergillus niger 12,000 Total bacteria 41,000

Aspergillus sydowii 12,000

Aspergillus ustus 28,000 Thermophilic actinomycetes 1,200

Penicillium brevicompactum 320,000

Penicillium species 4,000

 Total fungi 390,000

Room 29 Aspergillus niger 32,000 Actinomycetes 16,000

Curvularia lunata 4,000 Bacillus 84,000

Nonsporulating fungi 8,000 Gram negative rods 48,000

Phoma species 36,000 Gram positive cocci 36,000

Yeast 4,000 Total bacteria 180,000

 Total fungi 84,000

Thermophilic actinomycetes 1,200

Room 31 Aspergillus ochraceus 180,000 Actinomycetes 400

Nonsporulating fungi 4,000 Bacillus 18,000

Yeast 4,000 Gram negative rods 6,000

 Total fungi 190,000 Gram positive cocci 400

Total bacteria 25,000

Thermophilic actinomycetes 400

* Fungi cultured on malt extract agar (MEA) media at 23-26°C; bacteria cultured on tryptic soy agar (TSA) media at 23-26°C, 

except thermophilic actinomycetes bacteria cultured at 55°C.

†cfu/g = colony forming units per gram.
Page 40 Health Hazard Evaluation Report 2011-0096-3176

TTables ables ((con conttinued inued))

Table 3. Microbial agents cultured* from bulk material samples collected from inside ventilation insulation 

board supply ducts by NIOSH investigators on June 22, 2011, accounting office, Florida

Sample 

Description

Fungi Bacteria

Identification cfu/g† Identification cfu/g†

BLK 10

Cutout sample from 

HVAC-1 supply

duct above Room 3

Cladosporium cladosporioides 120,000 Bacillus 1,000

Verticillium lecanii 38,000 Gram negative rods 400

 Total fungi 158,000 Total bacteria 1,400

Thermophilic actinomycetes <100

BLK 11

Cutout sample from 

HVAC-4 supply

duct above hallway 

by Room 12

Acrodontium species 9,200,000 Bacillus 700

Cladosporium cladosporioides 100,000 Total bacteria 700

Total fungi 9,300,000

Thermophilic actinomycetes <100

*Fungi cultured on malt extract agar (MEA) media at 23-26°C; bacteria cultured on tryptic soy agar (TSA) media at 23-26°C, 

except thermophilic actinomycetes bacteria cultured at 55°C. 

†cfu/g = colony forming units per gram.
Health Hazard Evaluation Report 2011-0096-3176 Page 41

Table 4. Microbial agents identified with direct microscopic examination in bulk material samples 

collected from inside ventilation insulation board supply ducts by NIOSH investigators on June 22, 2011, 

accounting office, Florida

Sample Description Mold growth seen with underlying mycelial and/or 

sporulating structures*

Miscellaneous 

spores 

present†

General 

Impression

BLK 10

Cutout sample from 

HVAC-1 supply duct 

above Room 3

2+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth 

2+ Cladosporium species (spores, hyphae, conidiophores)

BLK 12

Tape lift sample from 

AHU-1 supply duct on 

roof

4+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth

4+ Cladosporium species (spores, hyphae, conidiophores)

BLK 11

Cutout sample from 

HVAC-4 supply duct 

above hallway by 

Room 12 

3+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth

1+ Cladosporium species (spores, hyphae, conidiophores)

BLK 14

Tape lift sample from 

HVAC-4 supply duct 

above hallway by 

Room 12

4+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth 1+ Cladosporium species (spores, hyphae, conidiophores)

BLK 16

Tweezed sample from 

HVAC-4 supply duct 

above hallway by 

Room 12

4+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth 3+ Cladosporium species (spores, hyphae, conidiophores)

BLK 13

Tape lift sample from 

AHU-4 supply duct on 

roof

4+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth

1+ Cladosporium species (spores, hyphae, conidiophores)

BLK 15

Tweezed sample from 

AHU-4 supply duct on 

roof 

4+ Sporothrix species (spores, hyphae, conidiophores) None Mold 

growth

3+ Cladosporium species (spores, hyphae, conidiophores)

* Quantities of molds are graded 1+ to 4+, with 4+ denoting the highest numbers. 

†Indicative of normal conditions (i.e., seen on surfaces everywhere), including basidiospores (mushroom spores), myxomycetes, 

plant pathogens such as ascospores, rusts and smuts, and a mix of saprophytic genera with no particular spore type 

predominating and a distribution of spore types usually seen outdoors
Page 42 Health Hazard Evaluation Report 2011-0096-3176 Figures Figure 1. Map with sampling locations.
Health Hazard Evaluation Report 2011-0096-3176 Page 43

Figures (continued)

Figure 2. Exterior of front of office building, June 2011.

Figure 3. Exterior of back of office building, June 2011.
Page 44 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 4. Roof-top air-handling units 1 (foreground) through 5 with condensate pipes 

that extend to roof drains, June 2011.

Figure 5. Roof drainpipe inside ceiling plenum, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 45

Figures (continued)

Figure 6. Roof drainpipe dropped through the exterior wall (exposed during 2006-7 

renovation) into the ground, October 2006 (picture courtesy of building manager).

Figure 7. Hallway inside accounting office, June 2011.
Page 46 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 8. Ceiling plenum, June 2011.

Figure 9. HVAC main trunk line, June 2011. 
Health Hazard Evaluation Report 2011-0096-3176 Page 47

Figures (continued)

Figure 10. HVAC main trunk line with multiple flexible ducts attached, June 2011.

Figure 11. Inside of an HVAC main trunk line, June 2011.
Page 48 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 12. Wall cavity inspection hole after sealing with tape in Hall 11 wall 

shared with Room 10, June 2011. 

Figure 13. Suspect mold in Room 3 at base of wall shared with Hall 5, October 2010 

(picture courtesy of building manager).
Health Hazard Evaluation Report 2011-0096-3176 Page 49

Figures (continued)

Figure 14. Suspect mold-damaged drywall removed in Room 3 at base of wall shared with 

Hall 5, October 2010 (picture courtesy of building manager).

Figure 15. Wall cavity inspection inside Hall 5 wall shared with Room 3, November 2010 

(picture courtesy of building manager).
Page 50 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 16. Wall cavity inspection, November 2010 (picture courtesy of building manager).

Figure 17. Wall cavity inspection inside Hall 5 wall shared with Room 3, November 2010 

(picture courtesy of building manager).
Health Hazard Evaluation Report 2011-0096-3176 Page 51

Figures (continued)

Figure 18. Wall cavity inspection inside Hall 5 wall shared with Room 3, November 2010 

(picture courtesy of building manager).

Figure 19. Ceiling stain in Room 23, June 2011.
Page 52 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 20. Top of stained ceiling tile in Room 23, June 2011.

Figure 21. Ceiling stain in Room 37 (kitchen), June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 53

Figures (continued)

Figure 22. Roof drain above ceiling stain in Room 37 (kitchen), June 2011.

Figure 23. Raised area of cloth wall paper in Room 3, June 2011.
Page 54 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 24. Water stains on window sill in Room 19, June 2011.

Figure 25. Blistered paint on window sill in Room 19, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 55

Figures (continued)

Figure 26. Vertical water marks on wall under window in Hall 11, June 2011.

Figure 27. Roof lap joints inside ceiling plenum, June 2011.
Page 56 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 28. Roof lap joints inside ceiling plenum, June 2011.

Figure 29. Rusty stain at a roof lap joint in ceiling plenum, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 57

Figures (continued)

Figure 30. Rusty stain at a roof lap joint in ceiling plenum, June 2011. 

Figure 31. Ill-fitting weather stripping on Hall 5 exterior door frame, June 2011.
Page 58 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 32. Ill-fitting weather stripping on door frame in Hall 5, June 2011.

Figure 33. Awning over Hall 5 exterior door

a) June 2011. b) September 2011 (courtesy of building manager). 

Figure 33. Awning over Hall 5 exterior door 

a) June 2011 b) September 2011 (Courtesy of building manager) 
Health Hazard Evaluation Report 2011-0096-3176 Page 59

Figures (continued)

Figure 34. Awning over Hall 11 exterior door, June 2011.

Figure 35. Oversized filter in AHU-2, June 2011.
Page 60 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

 

Figure 36. Water dripping into AHU-4 filter housing base and outside/return air mixing 

plenum, June 2011.

Figure 37. Inside supply duct immediately after fan in AHU-1, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 61

Figures (continued)

Figure 38. Inside supply duct after fan in AHU-4, June 2011.

Figure 39. Inside supply duct immediately after fan, June 2011.

a) AHU- 4. b) AHU-2 (light spots are sealant foam). 

Figure 39. Inside supply duct immediately after fan, June 2011. 

a) AHU- 4 b) AHU-2 (light spots are sealant foam) 
Page 62 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 40. Cooling coil in AHU-3, June 2011.

Figure 41. Cooling coil in AHU-4, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 63

Figures (continued)

Figure 42. Inside of AHU-1, June 2011.

Figure 43. Inside of AHU-2, June 2011.
Page 64 Health Hazard Evaluation Report 2011-0096-3176

Figures (continued)

Figure 44. Inside of AHU-3, June 2011.
Health Hazard Evaluation Report 2011-0096-3176 Page 65

Acknowledgements and

Availability of Report

The Respiratory Disease Hazard Evaluation and Technical 

Assistance Program (RDHETAP) of 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 (OSH) Act of 1970, 29 

U.S.C. 669(a)(6), or Section 501(a)(11) of the Federal Mine Safety 

and Health Act of 1977, 30 U.S.C. 951(a)(11), which authorizes 

the Secretary of Health and Human Services, following a written 

request from any employers 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.

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do no 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.

RDHETAP 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. 

This report was prepared by Rachel Bailey, Chris Piacitelli, 

Stephen Martin, Jr., Jean Cox-Ganser of RDHETAP. Site visit was 

conducted by Rachel Bailey and Chris Piacitelli. Industrial hygiene 

field assistance was provided by an environmental specialist from 

the local county health department. Desktop publishing was 

performed by Tia McClelland of RDHETAP. The authors thank 

Kathleen Kreiss and Nicole Edwards for their thoughtful review of 

this report.

Copies of this report have been sent to employee and management 

representatives at the accounting firm, the local and state health 

departments, and the OSHA Regional Office. This report is not 

copyrighted and may be freely reproduced. The report may be 

viewed and printed at www.cdc.gov/niosh/hhe/. Copies may be 

purchased from the National Technical Information Service (NTIS) 

at 5825 Port Royal Road, Springfield, Virginia 22161.
Below is a recommended citation for this report:

NIOSH [2013]. Health Hazard Evaluation Report: Evaluation of indoor environment 

quality at an accounting office, Florida. Morgantown, WV: U.S. Department of 

Health and Human Services, Public Health Service, Centers for Disease Control 

and Prevention, National Institutute for Occupational Safety and Health, NIOSH 

HETA No. 2011-0096-3176.

To receive NIOSH documents or information about 

occupational safety and health topics contact NIOSH at:

1-800-35-NIOSH (1-800-356-4674)

Fax: 1-513-533-8573

E-mail: pubstaft@cdc.gov

or visit the NIOSH web site at:

http://www.cdc.gov/niosh/hhe

Delivering on the Nation’s promise:

Safety and health at work for all people

through research and prevention.

 National Institute for Occupational 

Safety and Health