Health Hazard Evaluation Report 2014-0050-3234 Page 1

Evaluation of an Unpleasant Odor at an 

Aircraft Ejection Seat Manufacturer

HHE Report No. 2014-0050-3234

April 2015

Kendra Broadwater, MPH

Marie A. de Perio, MD

Scott E. Brueck, MS, CIH 

Nancy C. Burton, PhD, CIH

Angela R. Lemons, MS

Brett J. Green, PhD

U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health
Page 2 Health Hazard Evaluation Report 2014-0050-3234

Contents

Highlights...............................................i

Abbreviations ..................................... iii

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

Methods ............................................... 2

Results and Discussion........................ 4

Conclusions........................................ 14

Recommendations............................. 15

Appendix A ........................................ 18

Appendix B......................................... 22

Appendix C ........................................ 25

Appendix D ........................................27 

References......................................... 28

Acknowledgement............................33

The employer is required to post a copy of this report for 30 days at or near the 

workplace(s) of affected employees. The employer must take steps to ensure 

that the posted report is not altered, defaced, or covered by other material.

The cover photo is a close-up image of sorbent tubes, which are used by the HHE 

Program to measure airborne exposures. This photo is an artistic representation that may 

not be related to this Health Hazard Evaluation. Photo by NIOSH.
Health Hazard Evaluation Report 2014-0050-3234 Page i

We investigated an odor 

at an aircraft ejection seat 

manufacturer. We observed 

work processes and collected air 

samples for contaminants. Poor 

ventilation and poor bacterial 

control in metalworking fluid 

reservoirs could be contributing 

to the odor. We found 

2-methoxy-3,5-dimethylpyrazine 

(3,5-MDMP) in the air and 

in the metalworking fluid. It 

is likely that this chemical, 

which can be produced by 

bacteria, is causing the odor. We 

recommend decontaminating 

the metalworking machines, 

improving metalworking fluid 

maintenance, and improving 

ventilation.

Highlights of this Evaluation

The Health Hazard Evaluation Program received a request from the employer at a facility 

where aircraft ejection seats are made. Employees were concerned about a lingering odor 

that was first noticed in April 2013 and continued to be a problem. The odor remained in 

materials and goods after they left the facility.

What We Did

● We visited the facility in May 2014. 

● We interviewed employees about their work 

and health. 

● We examined the ventilation systems and 

measured ventilation airflow and comfort 

parameters in some areas. 

● We took air samples to analyze for 

metalworking fluid, volatile organic 

compounds, bacteria, and endotoxin. 

● We took bulk samples of metalworking fluid 

from machining reservoirs to analyze for 

microbial diversity and endotoxin.

● We looked at work practices and conditions.

What We Found

● It is likely that 2-methoxy-3,5-

dimethylpyrazine (3,5-MDMP, CAS 92508-

08-2) is causing the odor in the facility. This 

chemical may be produced by some of the 

bacteria found in the metalworking fluid.

● The most common work-related symptoms 

reported by employees were fatigue, headache, 

eye irritation, and runny nose or congestion, 

and cough.

● Ventilation systems and water diversion systems were not well-maintained. 

Condensation pans in air handling units had standing water and debris. Gutters were 

rusted through, causing them to be ineffective. 

● Air recirculation rates were high in some departments indicating poor general 

ventilation.

● Levels of metalworking fluid exposures in air reached about half of the NIOSH 

recommended limit.

● Genetic material from unexpected types of bacteria was found in the metalworking 

fluid and in the air. Endotoxin concentrations were high in the metalworking fluid. 
Page ii Health Hazard Evaluation Report 2014-0050-3234

● Employees who wore gloves used latex gloves when working with metalworking fluid. 

● Metalworking fluid was not well contained around the stock metal cutting machine.

What the Employer Can Do

● Repair and maintain building ventilation and water diversion systems. Modify 

ventilation systems that recirculate indoor air to introduce outdoor air. 

● Isolate the computer numerical control department from the rest of the facility with 

barrier walls or relocate it to a separate room. 

● Install a dedicated ventilation system in the computer numerical control department.

● Implement maintenance programs for managing metalworking fluid in the machines 

and recycling system.

● Develop and carry out a plan for metalworking machine decontamination.

● Improve metalworking fluid containment at the stock metal cutting machine.

● Provide non-latex gloves to employees to prevent the development of latex allergy.

What Employees Can Do

● Wear non-latex gloves when handling goods or doing tasks that require contact with 

metalworking fluids.

● Wash your skin with soap and water if you get metalworking fluid on your skin and 

after removing gloves.

● Wear heavy non-latex gloves to protect your hands from cuts when handling metal pieces.
Health Hazard Evaluation Report 2014-0050-3234 Page iii

Abbreviations

μg/mL microgram per milliliter

μL microliter

μm micrometer

BLAST Basic Local Alignment Search Tool

C Celsius

CFR Code of Federal Regulations

CFU/mL Colony forming units per milliliter

CLIA Clinical Laboratory Improvement Amendments

CNC Computer numerical control

CO2 Carbon dioxide 

DNA Deoxyribonucleic acid

EU Endotoxin units

EU/mL Endotoxin units per milliliter

EU/m3 Endotoxin units per cubic meter

F Fahrenheit

FDA Food and Drug Administration

ITS Internal Transcribed Spacer

3,5-MDMP 2-methoxy-3,5-dimethylpyrazine (CAS 92508-08-2)

3,6-MDMP 2-methoxy-3,6-dimethylpyrazine (CAS 19846-22-1)

mg/m3 Milligrams per cubic meter

mL Milliliter

NCBI National Center for Biotechnology Information

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

OTU Operational taxonomic unit

PCR Polymerase chain reaction

PEL Permissible exposure limit

rDNA Ribosomal deoxyribonucleic acid

REL Recommended exposure limit

spp. Species

TWA Time-weighted average

VOC Volatile organic compound
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Health Hazard Evaluation Report 2014-0050-3234 Page 1

Introduction

The Health Hazard Evaluation Program received a request from the employer at a facility 

where aircraft ejection seats are made. Employees were concerned about a lingering odor in 

the facility that they first noticed in April 2013 and health symptoms thought to be related to 

it. The odor reportedly permeated and remained in materials and goods of employees after 

they left the facility. We evaluated indoor environmental quality; sampled air for volatile 

organic compounds (VOCs), metalworking fluid, endotoxin, and microbial contaminants; 

analyzed bulk metalworking fluid for microbial diversity and endotoxin; and interviewed 

employees about their work and health during our site visit in May 2014. 

The single-story, 35,000-square-foot facility was built in the 1970s for use as a roller skating 

rink. It housed an electronics manufacturing company during the 1990s. The ejection seat 

manufacturing company has operated in the building since 2001. The company employed 

15–20 people from 2001 to 2005. The company increased production and the number of 

workers in 2005. It employed 134 workers at the time of our evaluation and operated 

24 hours per day, 5 days per week; employees worked 8-hour shifts. Most employees worked 

between the hours of 7:30 a.m. and 4:00 p.m. The company added 17,000 square feet of 

production space onto the original structure during the summer of 2013. This additional space 

was unoccupied at the time of our site visit. Dropped tile ceilings throughout the building 

varied in height from about 8 feet to 20 feet. Exterior walls consisted of two layers of steel 

with insulating foam between them. In office areas, drywall was attached to the steel walls by 

wooden studs. Most administrative offices were carpeted until early 2014. All carpet in the 

facility had been removed by the time of our site visit. 

The production process began with cutting and machining stock aluminum into smaller 

parts in enclosed metalworking machines. The facility had four fully enclosed computer 

numerical control (CNC) metalworking machines (three vertical machines and one horizontal 

machine) and one stock metal cutting machine. One machine, DHP4000, was equipped with 

a mist collector. The company used semi-synthetic water-miscible cutting oils to lubricate, 

cool, and remove chips during machining and cutting. The aluminum parts were heat treated 

after machining. Rough edges were smoothed in a tumbler with abrasive powders. Fabric 

treated with flame retardant was cut with a laser cutting machine equipped with local exhaust 

ventilation. Sewers used machines to sew fabric for the seats. Aluminum seat parts were 

painted in a down-draft paint booth. Ejection seats and component parts were inspected at 

multiple points during the production process. Seats were hand-assembled in the crashworthy 

department. Employees repaired flawed parts or seats in component repair. Parachutes for the 

ejection seats were packed in the paraloft department.

Odors

Odors are organic or inorganic compounds that trigger the sense of smell and can be 

perceived as pleasant or unpleasant. Some, but not all, compounds that cause odors can be 

health hazards. Some odorless substances are very hazardous to health, for example, carbon 

monoxide. The presence of odors can cause some people to suspect harmful exposures. 

Odors in a building are not always a sign that occupants are overexposed to chemicals, 
Page 2 Health Hazard Evaluation Report 2014-0050-3234

however. Some chemicals or compounds have a very low odor threshold, which means 

people can smell them even at very low levels. 

The odor in this building was initially described as a musty smell by some and a chemical 

smell by others. The odor reportedly absorbed into organic material, paper, cardboard, leather, 

clothing, and hair. It also reportedly lingered for weeks on objects after they left the facility. 

Metalworking Fluids 

Metalworking fluids are complex mixtures used to cool, lubricate, and remove metal chips 

from tools and parts during machining of metal stock. Metalworking fluids often contain 

other substances, including biocides, corrosion inhibitors, metal fines, tramp oils, and 

biological contaminants [NIOSH 1998; Burton et al. 2012]. Inhalation of metalworking 

fluid aerosols may irritate the throat, nose, and lungs and has been associated with chronic 

bronchitis, asthma, hypersensitivity pneumonitis, and worsening of pre-existing respiratory 

problems [Burton et al. 2012]. The National Institute for Occupational Safety and Health 

(NIOSH) recommends limiting exposures to metalworking fluid aerosols to 0.4 milligrams 

per cubic meter (mg/m3

) for the thoracic particulate mass, as a time-weighted average 

(TWA) concentration, for up to 10 hours per day during a 40-hour workweek [NIOSH 1998]. 

Detailed information on occupational exposure limits (OELs) is presented in Appendix B. 

Skin contact with metalworking fluids may cause allergic contact dermatitis or irritant contact 

dermatitis, depending on the chemical composition, additives and contaminants, 

type of metal being machined, and the exposed individual’s tendency for developing allergies 

[WISHA 2001]. Synthetic, semisynthetic, and soluble oil metalworking fluids are diluted 

with water, so excess bacteria may grow if metalworking fluid is not properly monitored 

and maintained. The Health and Safety Executive in the United Kingdom states that wellmaintained metalworking fluids should have bacterial concentrations below 103

 colony 

forming units per milliliter (CFU/mL) of fluid [HSE 2006]. Concentrations between 

103

 and 106 CFU/mL indicate reasonable control, and concentrations greater than 

106

 CFU/mL indicate poor control [HSE 2006]. The outer cell walls of Gram-negative 

bacteria may release lipopolysaccharide compounds called endotoxins when the bacteria 

die or multiply. Endotoxin is believed to cause adverse respiratory effects such as chronic 

bronchitis and asthma. Endotoxin concentrations are reported in endotoxin units (EU) 

per cubic meter (EU/m3

). In 2010, the Dutch Expert Committee on Occupational Safety 

recommended a health-based OEL for airborne endotoxin of 90 EU/m3

 [DECOS 2010]. No 

OELs for endotoxin have been established in the United States.

Methods

Our primary objectives were to evaluate the indoor environmental quality in the facility 

and identify potential sources of the offending odor. Our work included: (1) evaluation of 

the physical building and ventilation systems, (2) document review, (3) air sampling for 

metalworking fluid, endotoxin, microbial diversity, and VOCs, (4) microbial analysis of the 

bulk metalworking fluid, (5) observations of work practices, and (6) confidential medical 

interviews with employees.
Health Hazard Evaluation Report 2014-0050-3234 Page 3

Building and Ventilation Evaluation

We inspected the air-handling units, exhaust fans, gutters, downspouts on the roof, and the 

plenum above the dropped ceiling tiles. We looked for evidence of past or current water 

damage, water incursion, or fungi inside and outside of the building. We measured supply 

and exhaust airflow rates in the painting preparation and paint booth area with a TSI Model 

8371 AccuBalanceTM Air Capture Hood. We measured carbon dioxide with a TSI Model 

8554 Q-TRAK PlusTM Indoor Air Quality Monitor. 

Document Review

We reviewed metalworking fluid maintenance records, industrial hygiene reports, and 

metalworking fluid safety data sheets. We reviewed environmental sampling results and 

consultants’ reports regarding the odor and mold sampling. The consultants had identified 

mold growth in the conference room and heat treat area, which the company remediated 

before our site visit. The company hired a laboratory to analyze air filters for mycotoxins. 

They also hired a laboratory to analyze biological samples from employees and their family 

members for mycotoxins. We did not evaluate these mycotoxin analytical reports for reasons 

described in Appendix C. We reviewed maintenance and recycling best-practice protocols 

provided by the metalworking fluid manufacturer. We also reviewed company policies 

regarding metalworking fluid use and maintenance.

Air Sampling for Metalworking Fluid, Endotoxin, and 

Volatile Organic Compounds

We collected four full-shift, personal air samples to analyze for thoracic particle mass and 

extracted metalworking fluid mist in the CNC department. Thoracic sized particles have an 

aerodynamic diameter of 10 micrometers or less. These particles reach deeper into the lungs 

than particles larger than 10 micrometers. Thoracic particles sampled in this manner include 

all metal dusts, other particulates, and aerosols in addition to the aerosolized metalworking 

fluid itself. We noted the type of engineering controls and the employees’ locations and shift 

tasks. We collected eight area air samples for endotoxin with use of endotoxin-free sampling 

media. We collected eight area air samples with thermal desorption tubes, a qualitative 

sampling method to detect and identify VOCs. Details of the sampling and analysis methods 

are in Appendix A.

Bulk Metalworking Fluid Sampling for Viable Bacteria 

and Endotoxin

We collected three bulk samples of metalworking fluid, one each from the supply reservoir 

of three CNC machines. A commercial laboratory analyzed the bulk metalworking samples 

for bacteria, mycobacteria, and fungi using viable culture methods. When organisms grew 

in the cultures, the laboratory tested further to determine the species. Details on the culture 

media, incubation temperature, and incubation times used for the cultures are in Appendix 

A. The bulk samples from the machine reservoirs were also analyzed for endotoxin, which 
Page 4 Health Hazard Evaluation Report 2014-0050-3234

is a component of the cell wall of Gram-negative bacteria. Additionally, we analyzed the air 

space in the jars containing bulk metalworking fluid for VOCs.

Microbiological Diversity

We sent the three bulk metalworking fluid samples, each from a different CNC machine, 

and the 12 air samples for microbial diversity analysis. First, we amplified microbiological 

deoxyribonucleic acid (DNA) present in the air samples and in bulk metalworking fluids. 

Then we sequenced the DNA to identify which varieties of bacteria were present in these 

samples. We clustered the sequence data into operational taxonomic units (OTUs), a flexible 

term that refers to taxonomic placement (e.g., order, genus, or species) when analyzing DNA 

sequence data. Using sequences representative of each OTU, we searched for them within a 

database operated by the National Center for Biotechnology Information (NCBI) [Schloss 

et al. 2009]. This process resulted in a list of types of bacteria found in the air and bulk 

metalworking fluid. Details of the sampling and microbiological diversity analysis are in 

Appendix A.

Observations

We observed work practices and procedures in the facility, particularly in the CNC 

department. We noted handling practices and use of personal protective equipment.

Confidential Medical Interviews

We randomly selected 60/134 (45%) employees to participate in individual, semi-structured, 

confidential medical interviews. Employees who were not randomly selected were informed 

by the company via email that they could also be interviewed if they wished. During the 

interviews, we discussed their work, pertinent medical history, symptoms, and health 

concerns they related to the building.

Results and Discussion

Building and Ventilation Evaluation

Ducted supply airflow was provided to the building through 10 rooftop-mounted air-handling 

units. Four units were located on the west half of the roof, and six units were on the east 

half of the roof. We inspected three of the air-handling units. We observed standing water 

under the air intake of one of the units (Figure 1). Although it had rained in the previous 24 

hours, debris in the water, biological growth, and discoloration of the roof under the intake 

suggested that water had been pooled at this location for an extended period of time. We 

also observed standing water and an extensive amount of rust in the condensate drain pan 

of another air-handling unit. The condensate drain pan for a different air-handling unit was 

damp and contained rotted plant debris. The drain line for both of these drain pans appeared 

to be partially or completely plugged. Pooling of water under the air-handling unit intakes 

or in condensate drain pans for prolonged periods may increase the likelihood of fungal or 

bacterial growth in the water. A filter for the air-handling unit serving the main offices on 
Health Hazard Evaluation Report 2014-0050-3234 Page 5

the west side of the building had evidence of water damage, most likely due to condensation 

from the air-conditioning coils that did not drain properly into the drain pan. 

Figure 1. Standing water under intake of an air-handling unit on the roof. Photo by NIOSH.

In October 2013, the company had two large constant-volume exhaust fan units installed 

across the center of the roof. Exhaust air was not ducted to these units but was exhausted 

from the plenum space above the ceiling tiles. Some ceiling tiles had been replaced with 

plastic honeycomb tiles to provide a pathway for entry of air into the plenum space. 

However, ceiling tiles were missing at several locations, thus allowing unplanned pathways 

for air into the plenum space. The exhaust air from the fans was released through the top of 

the units, about 3 feet above the roof surface. Because of the low release point and proximity 

of the air-handling units on the roof, exhaust air could be recaptured by the outdoor air 

intakes, depending on prevailing wind speed and direction. The company did not have 

information on the supply rate of the air-handling units or exhaust rate of the fans.

We observed some sections of roof gutters and downspouts that had completely rusted 

through, making them ineffective for collecting and properly diverting water away from the 

building (Figure 2). The gutters and downspouts on the west side of the building drained 

directly to the ground near the foundation. Because grading of the ground on the west side 

of the building sloped toward the building, water draining from the roof or down the slope 

did not effectively drain away from the building and sometimes pooled near the foundation. 

Employees reported at least one incident of substantial water intrusion into the building 

through the lower part of the west-side walls during the previous winter. Employees also 

reported regular water incursion into the building at other locations. We saw evidence of 

water damage to walls and ceiling tiles at several locations, indicating leaks through the roof. 

We also saw several locations where the roof had been patched to repair leaks.
Page 6 Health Hazard Evaluation Report 2014-0050-3234

Figure 2. Gutter with a large hole rusted through. Photo by NIOSH.

Company personnel had found fungal contamination on some walls of the building. In 

June 2013, the company hired a contractor to have fungal contamination remediated in the 

conference room and in the heat-treat department. In September 2013, the same contractor 

remediated fungal contamination in the building entry area and removed the vestibule from 

the front of the building. According to the employer, the contractor’s remediation involved 

(1) removing visible fungus from the walls and removing drywall when fungi was behind 

it, (2) spraying affected areas with a disinfectant to remove fungal colonies and dispersal 

structures such as spores, and (3) applying a fungal-resistant clear coat after treated areas 

were dry. 

The company started using carbon-impregnated air filters in the air-handling units in 

April 2013 to help reduce the odor. Maintenance staff reportedly replaced the filters every 

3 months. The company also installed hydrogen peroxide ionizers in the ventilation ducts and 

throughout the facility. Employees reported no reduction in odors after installation of the air 

filters and ionizers.

Outdoor temperatures were 75.2–80.5 degrees Fahrenheit (F), and the average relative 

humidity outdoors was 40% on the days of our evaluation. Indoor temperatures were 

69.3°F–77.5°F, and the indoor relative humidity levels were 36%–56%. Carbon dioxide 

(CO2) concentrations ranged from 1,107–1,820 ppm in the paraloft, component repair, 

document control, and inspection departments. We found that each of these departments was 

ventilated with an independent air-handling unit, which drew make-up air from inside the 

building rather than incorporating outdoor air. Recirculating only indoor air can cause an 

increase in the relative concentration of indoor air contaminants, such as the VOCs used or 

created during the manufacturing process and CO2, which is sometimes used as a marker of 

ventilation effectiveness because it is a natural product of human respiration. 

Measurements of supply and exhaust airflow in the paint-preparation room indicated that the 

air supply was substantially greater than its air exhaust. Because of this supply-to-exhaust 
Health Hazard Evaluation Report 2014-0050-3234 Page 7

imbalance, the paint-preparation room was under positive pressure relative to surrounding 

areas, increasing the likelihood that solvent and paint vapors would move to the surrounding areas.

Air Sampling for VOCs

Qualitative sampling revealed the presence of styrene and methyl ethyl ketone in all 

sampling locations. Although the sampling methods were not quantitative, we found 

that indoor concentrations were relatively higher than outdoor concentrations. These 

findings were not surprising. Methyl ethyl ketone was used to clean and remove excess 

oil from machined parts in multiple departments. Styrene was an ingredient of the 

abrasive product used in the tumbler in the heat-treat area. Other VOCs found on the 

sampling media include benzaldehyde, methyl vinyl ketone, dimethylpyrazine, phenol, 

decamethylcyclopentasiloxane, phenoxyacetone, ethyl hexanol, acetone, and isopropanol. 

A consultant, who reported the findings of air sample testing in April 2014, identified the odor 

as 2-methoxy-3,6-dimethylpyrazine (3,6-MDMP, CAS 19846-22-1). Methoxypyrazines are 

known to have low odor thresholds and can have a variety of odors, including musty, earthy, 

moldy, acrid, and “chemical” [Contis et al. 1998]. In our area air samples and headspace of 

bulk samples of metalworking fluid, we identified 2-methoxy-3,5-dimethylpyrazine (3,5-

MDMP, CAS 92508-08-2) as the primary isomer. We also identified 3,6-MDMP, but at much 

lower levels. No research studies have reported on the toxicity of 3,5-MDMP. However, like 

other methoxypyrazines, this isomer has a very low odor threshold and its odor has been 

characterized as disagreeable and musty. The isomer has also been associated with odiferous 

metalworking fluids [Mottram et al. 1984; Muller and Rappert 2010]. 

On the basis of these findings and odor characteristics, it is likely that 3,5-MDMP is 

causing the unpleasant, persistent odor in the facility. Additionally, NIOSH investigators 

who visited the worksite noted that the odor of the 3,5-MDMP standard used in the NIOSH 

laboratory smelled remarkably similar to the facility odor. A variety of bacteria produce 

dialkyl methoxypyrazines, including 3,5-MDMP. Some bacteria have been demonstrated 

to produce 3,5-MDMP specifically, including Rhizobium excellensis, Serratia odorifera, 

and Chondromyces crocatus [Chatonnet et al. 2010]. These organisms were first identified 

as the source of 3,5-MDMP in tainted wine corks, with Rhizobium excellensis believed 

to be the main source [Chatonnet et al. 2010]. Rhizobium bacterial species generally are 

found in soil. Several bacteria within the phyla Proteobacteria, Bacteroides, Firmicutes, 

and Actinobacteria are known to produce an array of pyrazines, including 3,5-MDMP. For 

additional information, see Appendix D for various bacterial species that produce 3,5-MDMP 

and related methoxypyrazines.

Air Sampling for Metalworking Fluid

Personal thoracic metalworking fluid exposures ranged from 0.08 to 0.20 mg/m3 and did 

not exceed the NIOSH recommended exposure limit (REL) for thoracic metalworking fluid 

mist of 0.4 mg/m3. These concentrations equate to 20%–50% of the NIOSH REL. All of the 

sample concentrations were above the minimum detectable concentration. However, three 

of the four sample concentrations were between the minimum detectable concentration and 
Page 8 Health Hazard Evaluation Report 2014-0050-3234

minimum quantifiable concentration, which means there is more uncertainty associated with 

these values.

Our full-shift, area air samples for metalworking fluid mist showed concentrations ranging 

from 0.27–0.74 mg/m3

 in the CNC area and 0.22 mg/m3 in a room adjacent to the CNC area, 

where the CNC programmer worked. These samples demonstrated that metalworking fluid 

migration is not well-controlled and mist moves from production areas into non-production 

areas.

Microbials in Bulk Metalworking Fluid

The total bacterial count was 1.7 × 107 CFU/mL to 4.1 × 107 CFU/mL in the three bulk samples 

of metalworking fluid. Several bacteria were isolated in the metalworking fluid samples. The 

microbiology laboratory only reported the three bacteria with the highest counts for each 

sample. Across the three samples, the primary bacteria isolated were Cupriavidus metallidurans, 

Corynebacterium species (spp.), Brevundimonas diminuta, and Alcaligenes faecalis. 

Bacteria can flourish within metalworking fluid systems, especially within water-miscible 

metalworking fluids. The sample concentrations we measured were in the Health and Safety 

Executive category of poor control of bacterial contamination [HSE 2006]. According to the 

metalworking fluid manufacturer, this system of metalworking fluid was expected to develop 

a culture of one specific bacterial species, Pseudomonas oleovorans [Kuenzi et al. 2014]. 

However, this bacterium was not one of the top three species found in our evaluation. This 

indicates poor control of the microbiota of the metalworking fluid system.

Mycobacterium species organisms were not detected in any of the samples. Fusarium species 

of fungi, common in soil, were detected in two samples at low concentrations (5 CFU/mL). 

The laboratory found no fungus in the third metalworking fluid sample. 

Microbial Diversity in Air and Bulk Metalworking Fluid

We found relatively low levels of fungal DNA in the air and bulk metalworking fluid 

samples. We selected bacteria for further sequencing analysis on the basis of the preliminary 

results and low yield of fungal DNA from these samples. 

We clustered the DNA sequences into 152 individual OTUs and identified 148 unique 

bacterial OTUs. Within the bacterial OTU dataset, 76% were ≥ 97% identical to reference 

16S bacterial sequences in the NCBI database. Additionally, we placed OTUs in Plantae 

(n = 4). We identified a large number of OTUs in metalworking fluid control samples, 

field blanks, and reagent controls because of bacterial contaminants from the environment, 

supplies, or reagents used throughout the sample collection and extraction processes. This 

is a common limitation associated with these genomic approaches to assessing bacterial 

diversity and indicates why it is important to utilize appropriate controls during extraction. 

All OTUs identified from the controls were removed and not included in the analysis of air 

and metalworking fluid samples. 

Overall, sequencing analysis identified 23 clones in the bulk used metalworking fluid. 
Health Hazard Evaluation Report 2014-0050-3234 Page 9

Samples from DHP4000 (n = 8) and DMV5025 (n = 10) CNC machines had the greatest 

number of clones; in contrast, samples from HP9 (n = 2) and HP11 (n = 3) CNC machines 

had the fewest. The clones were derived from the bacterial phyla Proteobacteria (39%), 

Firmicutes (39%), and Actinobacteria (22%). In the air sample sequence analysis, we 

identified a total of 48 clones, and they were derived from the bacterial phyla Proteobacteria 

(33%), Firmicutes (29%), Actinobacteria (25%), and Bacteroidetes (13%). Samples from the 

outdoors (n = 17), the crashworthy area (n = 5), and the front office (n = 8) had the greatest 

number of clones, compared to those identified in the 9 other air samples (range: 0–4 clones).

The preliminary Sanger sequencing analysis demonstrated that bacteria were present in 

both air and metalworking fluid samples. The diversity of bacteria appeared to be broader 

in air samples, in which greater numbers of clones and bacterial phyla were identified than 

in metalworking fluid samples. Compared with the culturable bacteria datasets reported 

above, Sanger sequencing data identified Brevundimonas diminuta in metalworking 

fluid samples but not Cupriavidus metallidurans; however, in the metalworking fluid 

sequencing analysis, we identified a variety of other betaproteobacteria in the same family 

(Burkholderiaceae). The Sanger sequencing analysis identified other culturable bacteria, 

including Corynebacterium spp. and Alcaligenes faecalis, but these were also present in 

several internal controls included in the analysis so they may not have originated from 

the workplace samples. We did not identify sequences from the primary bacteria species 

expected in the metalworking fluid, Pseudomonas oleovorans. This, along with the results 

from the cultured samples, suggests that the metalworking fluid was not populated with 

Pseudomonas oleovorans, the bacterium expected by the manufacturer. 

Review of the scientific literature suggests that many bacterial orders produce odor-causing 

pyrazines (Appendix D). Pyrazine production by these organisms can vary, depending on 

the culture conditions. The Proteobacteria species known to produce 3,5-MDMP, including 

Rhizobium excellensis (Rhizobiales order), Serratia odorifera (Enterobacteriales order), 

and Chondromyces crocatus (Myxococcales order), were all identified in tainted wine 

corks [Chatonnet et al. 2010]. We did not identify these specific organisms in the Sanger 

sequencing analysis. However, we found sequences derived from the Proteobacteria order, 

Rhizobiales, as well as orders thought to produce other types of pyrazines (Bacteriales, 

Actiniomycetales, and Sphingobacteriales), in both air and metalworking fluid samples. 

Biofilms are aggregates of microorganisms, including bacteria. Frequently, the bacteria 

produce a protective extracellular polymeric substance and adhere to each other or surfaces. 

In this case, biofilms can adhere to components of the metalworking fluid systems including 

the CNC interior, metalworking fluid reservoirs, recycling system containers, and even the 

surfaces of the machinery. Biofilms are very complex and can be difficult to remove once 

they are established [Lucchesi et al. 2012; Trafny 2013]. Bacteria within the biofilm may 

or may not be represented in bulk fluid samples. Biofilms can provide inoculating bacteria, 

which repopulate fresh metalworking fluid after cleaning or maintenance [Trafny 2013].

Endotoxin in Air and Bulk Metalworking Fluid 

We took eight area air samples for endotoxin throughout the facility and outdoors. 
Page 10 Health Hazard Evaluation Report 2014-0050-3234

Endotoxin is an indicator of bacterial contamination of the metalworking fluid. Endotoxin 

concentrations, shown in Table 1, ranged from below the limit of detection to 21 EU/m3. 

Airborne endotoxin was highest in the main office area and in the metal machining (CNC) 

department, at 18 EU/m3 and 21 EU/m3, respectively. No samples exceeded the Dutch Expert 

Committee on Occupational Safety–recommended limit of 90 EU/m3 [DECOS 2010].

Table 1. Area air sample results for endotoxin on May 8, 2014

Location Time

(min)

Volume

(m3)

Endotoxin

concentration

(EU/m3)

Paraloft 411 0.82 1.3

Outdoors 490 0.96 ND

Crashworthy assembly 501 1.00 ND

Heat treat 495 0.98 ND

Office, main, desk 524 1.05 18

CNC department desk 503 1.00 21

Stockroom 500 1.00 ND

Conference room 544 1.09 1.7

ND = not detected; the minimum detectable concentrations 

ranged from 0.50 to 0.52 EU/m3.

We analyzed the bulk metalworking fluid samples from four machine reservoirs for 

endotoxin. Endotoxin concentrations in the bulk metalworking fluid samples were 

77,300–527,000 endotoxin units per milliliter (EU/mL). The concentrations of endotoxin 

were high compared to those reported in the scientific literature. Simpson and associates 

found endotoxin ranging from the limit of detection to 1,870,000 EU/mL in 154 water-based 

metalworking fluid samples [Simpson et al. 2003]. The median endotoxin concentration 

for these samples was 8,039 EU/mL [Simpson et al. 2003]. In a study of three facilities, 

Cyprowski and associates [2007] found that the average concentration of bacterial endotoxins 

in the used metalworking fluids was 773 EU/mL. Endotoxin concentrations ranged from 220 

to 1,700 EU/mL in a manufacturing facility for steel roller bearings [NIOSH 2006].

Document Review

At the time of the evaluation, the facility used a water-miscible, mineral oil-based 

metalworking fluid that contained 45%–65% mineral oil, 30%–50% emulsifiers, 1%–5% 

polar additives, 5%–15% chlorinated paraffin, and 1%–5% stabilizer and inhibitors, per the 

product safety data sheet [Blaser Swisslube Inc. 2010].

According to maintenance documentation, at the time of our evaluation the metalworking 

fluid in each of the four CNC machines had been replaced one time since February 2012. The 

metalworking fluid in two machines (HP9 and HP11) had been replaced in February 2012; 

the other two machines (DHP4000 and DMV5025) underwent metalworking fluid changes in 

April 2013 and August 2013. At the time of our evaluation, the metalworking machines had 

reservoirs that utilized skimmers to remove tramp oils. Metalworking fluid was recycled by a 

gravitational recycling system in the CNC department.

Consultants who evaluated metalworking fluid exposures at the facility in July 2012 noted 
Health Hazard Evaluation Report 2014-0050-3234 Page 11

that airborne metalworking fluid was poorly controlled, especially when the mist collector 

was not used. 

Metalworking fluid was added regularly to the CNC machines, but the additions were not 

documented. The pH of the metalworking fluid was reportedly measured and tracked every 

day. In May 2014, the fluid manufacturer’s laboratory tested the metalworking fluid. The 

results showed that the odor of the metalworking fluid was unpleasant and that magnesium 

levels were higher than company-established tolerance limits. All other measures, including 

pH, sulfide, conductivity, calcium, calcium carbonate, chloride, sulfate, nitrate, nitrite, 

and aerobic bacteria, were within tolerance limits. The test showed aerobic bacteria 

concentrations less than 107

 CFU/mL (the manufacturer’s recommended range is to maintain 

concentrations greater than 105

 CFU/mL). In contrast, the United Kingdom Health and Safety 

Executive recommends a limit of 103

 CFU/mL for metalworking fluids [HSE 2006]. 

Observations

We observed that most employees used powder-free latex gloves when handling metal and 

metalworking fluid. Employees noted that the gloves protected them against cuts from sharp 

edges and prevented dermal exposure to metalworking fluid. We observed one employee 

with bare hands, handling metal coated in metalworking fluid, while using the metal-cutting 

machine. Although it is prudent to use gloves when working with metalworking fluid, latex 

can cause sensitization and result in local and systemic allergic reaction [OSHA 2008], so 

other materials should be selected. 

Oil from the stock metal cutting machine splashed onto the ground, creating a slip hazard 

(Figure 3). Employees put sorbent pads on the ground to absorb excess metalworking fluid 

and prevent slips. Used sorbent pads were put into a trash can to drain off metalworking fluid. 

Once the metalworking fluid was removed, sorbent pads were reused. The trash can was full 

during our evaluation. According to the company, this practice was discontinued after our site 

visit in May 2014. 

Figure 3. Stock metal cutting machine. Photo by NIOSH.
Page 12 Health Hazard Evaluation Report 2014-0050-3234

We observed one employee wearing a Moldex® (model 2740R95) filtering facepiece 

respirator. The employee wore the respirator voluntarily because of concern about exposure 

to an unknown agent causing the odor. The employee did not recall being provided with 

Appendix D from the Occupational Safety and Health Administration (OSHA) respiratory 

protection standard 29 CFR 1910.134 (Information for Employees Using Respirators When 

Not Required Under Standard). However, managers reported that all employees had a signed 

Appendix D form in their personnel files. 

Confidential Medical Interviews and Reported Health 

Symptoms

We interviewed 81 (60%) of 134 employees during the visit. This included 53 (88%) of 

the 60 randomly selected employees and an additional 28 employees who asked to be 

interviewed. The remaining seven randomly selected employees were not working or were 

not available on the interview days. 

The median age of interviewed employees was 50 years (range: 21–75 years). Forty-seven 

(58%) were male; 34 (42%) were female. The median amount of time worked at the facility 

was 6.75 years (range: 6 months to 14 years). The median number of hours worked per 

week at the facility was 40 hours (range: 36–60 hours). Interviewed employees included 

production, administrative, and managerial workers.

During the interviews, we asked employees if they were aware of any current water leaks, 

moisture problems, or mold problems in the facility. Seventy-three (90%) of employees 

reported they were aware of such problems. Reported problems included roof leaks throughout 

the building and mold problems in the cafeteria, conference room, and heat-treat area.

We also asked employees if they had noticed unusual odors in the facility in the 4 weeks 

prior to the interview. All but three employees (96%) reported noticing unusual odors during 

this period. Most employees reported they first noticed the odor in April 2013. Reported odor 

locations included the parking lot and throughout the building. Stronger odors were noted 

in the front vestibule, conference room, accounting office, CNC area, and maintenance area. 

Thirty-eight interviewed employees (49%) reported not knowing what the source of the odor 

was. Hypothesized sources by the other 40 employees included mold, stagnant water, soil/

groundwater, and metalworking fluid from the CNC machines.

Of the 81 interviewed employees, 7 (9%) reported no symptoms in the previous 4 weeks 

that they thought were related to working in the facility. Of the 74 (91%) who did report 

symptoms, the most commonly reported were fatigue (80%), headache (64%), eye irritation 

(64%), and runny nose/congestion (63%). Employees who were randomly selected 

employees for interviews and employees who asked to be interviewed had similar reported 

prevalence of any symptom and also the most commonly reported symptoms above.

Twenty-three interviewed employees (28%) reported skin rash; they represented production, 

administrative, and managerial staff and worked in various primary locations including 

the sewing department, crashworthy department, accounting office, main office, and 

CNC department. Seventeen interviewed employees (21%) reported having experienced 
Health Hazard Evaluation Report 2014-0050-3234 Page 13

psychological and/or emotional distress related to the odor experienced in the building in the past 

4 weeks. Table 2 summarizes the work-related symptoms reported during medical interviews.

Table 2. Work-related symptoms in the previous 4 weeks, 

reported by interviewed employees

Work-related symptom No. (%) of employees

(N = 81)

Fatigue 65 (80)

Headache 52 (64)

Eye irritation 52 (64)

Runny nose or congestion 51 (63)

Cough 44 (54)

Sinus problems 43 (53)

Sore throat 40 (49)

Dizziness/lightheadedness 35 (43)

Shortness of breath 35 (43)

Muscle aches 30 (37)

Skin rash 23 (28)

Wheezing 18 (22)

Nosebleed 17 (21)

Chest pain 13 (16)

Loss of appetite 10 (12)

Other* 32 (40)

*The most common other symptoms included a metallic taste 

and dry or itchy skin. 

We asked employees about underlying medical conditions. Thirty-two interviewed 

employees (40%) reported having one or more conditions consistent with atopy, a 

presdisposition to allergic disease (defined as history of asthma, allergic rhinitis/hay fever, 

or eczema). Specifically, 28 (35%) reported a history of hay fever/allergic rhinitis, 7 (9%) 

reported a history of asthma, and 2 (2%) reported a history of eczema. Seventeen employees 

(21%) reported being a current smoker. 

Many of the symptoms reported by these employees, such as fatigue, headache, eye 

irritation, and runny nose/congestion, are common in the general population [Lipscomb et 

al. 1992; Barsky and Borus 1995; Heyworth and McCaul 2001]. Nevertheless, over 90% of 

interviewed employees reported symptoms they experienced in the previous 4 weeks that 

they believed to be work-related. It is likely these symptoms are multifactorial in origin. 

First, the symptoms in some employees may be attributed to allergic rhinitis or hay fever 

from mold, dust, pollen, or other allergens; 35% of the interviewed employees reported 

a history of allergic rhinitis/hay fever. Second, it is also possible that insufficient outdoor 

air introduced through the ventilation system into the building could be contributing to 

or exacerbating symptoms. Too little outdoor air mixing in with indoor air can further 

concentrate existing contaminants, including chemicals used in and created during the 
Page 14 Health Hazard Evaluation Report 2014-0050-3234

manufacturing process. For example, styrene and methyl ethyl ketone are known skin and 

mucous membrane irritants. Third, it is also possible that symptoms in some employees could 

be associated with the 3,5-MDMP odor. 

Odors may produce health symptoms by three mechanisms. First, symptoms can be induced 

by exposure to odorants at levels that also cause irritation. Therefore, irritation, rather 

than the odorant, is the cause of the symptoms. Second, health symptoms from odorants 

at nonirritant concentrations, such as hydrogen sulfide, can be due to innate or learned 

aversions. Third, symptoms may be due to a co-pollutant, such as endotoxin, that is part of 

an odorant mixture [Schiffman and Williams 2005]. It is possible that symptoms reported by 

facility employees could be associated with all three mechanisms but also could be associated 

with non-occupational factors. In persons with existing health problems, such as asthma or 

chronic respiratory problems, odors can also worsen pre-existing symptoms. Odors have been 

found to affect the physiological and psychological responses of individuals with asthma 

[Beach et al. 1997; Jaén and Dalton 2014].

We found that 28% of interviewed employees reported a skin rash in the previous 4 weeks 

they believed was work-related. Skin rash was reported by production, administrative, and 

managerial employees. However, since we did not ask about specific diagnoses or specific 

locations of the rashes on the body in our interviews, it is difficult to hypothesize the cause. 

Employees were concerned that the presence of mycotoxins could be causing their 

symptoms. During our visit, we discussed the limitations and risks of biological testing for 

mycotoxins. Despite our recommendation against proceeding with this type of testing, prior 

to our site visit, the company had arranged mycotoxin testing of employee urine specimens 

through a contract laboratory. Because of the problems with this type of testing, we do not 

believe that the results can be used to say anything about employee symptoms and exposures 

at the facility (Appendix C).

Conclusions

2-Methoxy-3,5-dimethylpyrazine (3,5-MDMP) was the primary isomer found in area air 

and bulk samples of metalworking fluid and is the likely cause of the persistent, unpleasant 

odor. 3,5-MDMP and other methoxypyrazines haves been found to cause bad odors in 

metalworking fluid in the past, and a few species of bacteria are known to produce 

3,5-MDMP. Bacteria belonging to the same order that produce 3,5-MDMP were identified in 

our analysis of air and bulk metalworking fluid samples, and may be contributing to the high 

concentrations of endotoxin found in the metalworking fluid. We found metalworking fluid 

mist in the air including in areas outside of where the fluids are used. Throughout the facility 

we found methyl ethyl ketone, styrene and other VOCs. These chemical and biological 

contaminants and odors may be contributing to health symptoms reported by employees 

although it is likely that the reported symptoms are multifactorial in origin.
Health Hazard Evaluation Report 2014-0050-3234 Page 15

Recommendations

On the basis of our findings, we recommend the actions listed below. We encourage the 

company to use a labor-management health and safety committee or working group to 

discuss our recommendations 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 facility. 

Our recommendations are based on an approach known as the hierarchy of controls 

(Appendix B). 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 

personal protective equipment may be needed.

Engineering Controls

Engineering controls reduce employees’ exposures by removing the hazard from the process or by 

placing a barrier between the hazard and the employee. Engineering controls protect employees 

effectively without placing primary responsibility of implementation on the employee. 

1. Isolate the CNC department to prevent metalworking mist from migrating to adjacent 

areas. Possible methods may include (1) spatial isolation, such as constructing walls or 

moving equipment to a less central location, and (2) providing additional ventilation. 

Do not recirculate air from the CNC department into other areas of the facility. Maintain 

negative pressure relative to adjacent areas once the CNC department is isolated. 

2. Modify the facility ventilation systems to incorporate outdoor air supply to the 

paraloft, component repair, document control, and inspection departments. 

3. Repair the roof, gutters, and downspouts to ensure water is diverted away from the 

building. Excavate and change the grade on the west side of the building to move 

rainwater away from the building foundation and prevent flooding. 

4. Increase the height of the exhaust fan units above the roofline to decrease the 

likelihood of re-entrainment of building exhaust air. 

5. Evaluate the ventilation in the paint room and paint booth. Bring the paint room under 

negative pressure relative to adjacent areas. Do not recirculate air from this department 

to other areas of the facility. 

6. Install containment around the stock metal cutting machine to prevent metalworking 

fluid from dripping onto the ground, creating a slip hazard.
Page 16 Health Hazard Evaluation Report 2014-0050-3234

Administrative Controls

Administrative controls are employer-dictated work practices and policies to reduce or 

prevent hazardous exposures. Their effectiveness depends on employer commitment and 

employee acceptance. Regular monitoring and reinforcement are necessary to ensure that 

policies and procedures are followed consistently.

1. Develop a decontamination plan for the CNC machines (including tramp oil removal 

equipment), metalworking recycling system containers, and all instrumentation that 

contacts metalworking fluid during normal operations. Consult with the metalworking 

fluid manufacturer for guidance. When developing a decontamination plan, consider the 

persistence potential of biofilms that may re-inoculate fresh metalworking fluid. Once 

all components of the metalworking fluid system have been decontaminated, all used 

metalworking fluid should be disposed of and replaced with new metalworking fluid.

2. Institute the metalworking fluid management plan that was distributed in July 2014. 

Consult with the metalworking fluid manufacturer to identify best practices for 

metalworking fluid maintenance and recycling, including change-out and cleaning 

schedules as well as troubleshooting odors. A good metalworking fluid management 

plan includes procedures for maintaining metalworking fluid, guidelines for 

metalworking fluid testing and analysis, procedures for mist collector maintenance, 

and development and maintenance of employee training plans and records. The 

management plan should include the maintenance and monitoring of metalworking 

fluids undergoing the recycling process. If not properly maintained, the recycling 

reservoirs can harbor undesirable and unexpected bacteria. The metalworking fluid 

manufacturer recommends cleaning coolant systems and replacing used metalworking 

fluid annually [Blaser Swisslube Inc. 2013]. 

3. Develop and adhere to an air handler and ventilation system maintenance schedule. 

This should include replacing water-damaged and rusted parts and inspecting air 

filters, belts, and drip pans. 

4. Do not store used, saturated sorbent pads indefinitely. Employ a procedure for 

removing metalworking fluids and returning the pads to use quickly or disposing 

of them. Extended storage of saturated sorbent pads can contribute to uncontrolled 

microbial growth and odors. Consider using a spinner rather than gravitational 

methods to reduce metalworking fluid removal time. Discard metalworking fluid 

removed from sorbent pads. 

5. Implement a medical monitoring program for employees who are exposed to metalworking 

fluid mist at half of the REL. Consider including all employees who are exposed to 

metalworking fluid in the air or on their skin in the medical monitoring program. A 

medical monitoring program helps prevent, identify, and manage skin and respiratory 

disease among included employees. It includes preplacement or initial examination, 

periodic examination, detailed examination for a subset of employees, physician’s reports 

and follow-up evaluations. More information about medical monitoring can be found 

in the NIOSH document “What You Need to Know About Occupational Exposure to 

Metalworking Fluids” at http://www.cdc.gov/niosh/pdfs/98-116.pdf.
Health Hazard Evaluation Report 2014-0050-3234 Page 17

6. Conduct periodic air sampling for metalworking fluids on CNC employees and 

others who work in adjacent areas. Additionally, repeat air sampling when process or 

equipment changes occur. Personal monitoring, rather than area air monitoring, should 

be performed to obtain exposure data that can be compared to OELs.

7. Evaluate the use of methyl ethyl ketone and other solvents in the manufacturing 

process. Develop protocols for using methyl ethyl ketone and keep use records in 

every department where it is being used. Use these records to identify where solvent 

use can be reduced or eliminated or ventilation improvements can be made to reduce 

the ambient concentration of VOCs in the facility. 

8. Encourage employees with work-related health concerns to seek medical care from 

qualified medical professionals. Certification by medical specialty boards can be found 

by checking the American Board of Medical Specialties website at http://www.abms.org. 

9. 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.

10.Encourage employees to evaluate the quality of the health information that they find. It 

is important to ensure that health information is reliable, up-to-date, and unbiased. The 

National Library of Medicine and the National Institutes of Health offer guidelines for 

evaluating the quality of health information on the Internet (http://www.nlm.nih.gov/

medlineplus/evaluatinghealthinformation.html). 

Personal Protective Equipment

Personal protective equipment is the least effective means for controlling hazardous 

exposures. Proper use of personal protective equipment requires a comprehensive program 

and a high level of employee involvement and commitment. The right personal protective 

equipment must be chosen for each hazard. Supporting programs such as training, changeout schedules, and medical assessment may be needed. Personal protective equipment should 

not be the sole method for controlling hazardous exposures. Rather, personal protective 

equipment should be used until effective engineering and administrative controls are in place.

1. Provide non-latex gloves and require all employees to use them when handling 

materials that are covered with metalworking fluid and when using methyl ethyl 

ketone to clean parts.

2. Offer heavy-duty non-latex protective gloves to CNC operators for hand protection 

from cuts and metalworking fluid. Thick nitrile gloves are a suitable alternative. 

3. Ensure employees who voluntarily wear respirators understand the requirements 

of voluntary respirator use per Appendix D (Information for Employees Using 

Respirators When Not Required Under Standard) from the OSHA respiratory 

protection standard [29 CFR 1910.134]. 
Page 18 Health Hazard Evaluation Report 2014-0050-3234

Appendix A: Methods

Metalworking Fluid Sampling and Analysis

Air samples for metalworking fluid analyses were collected by using 37-mm closedfaced three-piece cassettes containing a pre-weighed 2-micrometer-pore-size 

polytetrafluoroethylene filter and support pad. The sampling train consisted of a BGI thoracic 

cyclone, 37-millimeter cassette, and Tygon® tubing connecting the sampling assembly to 

SKC Air Check® 2000 air-sampling pumps. A sampling rate of 1.6 liters per minute was 

used to collect the thoracic fraction of the aerosol. Each pump was calibrated before and after 

use. The sampling medium was attached to the employee’s lapel within the breathing zone 

(defined as an area in front of the shoulders with a radius of 6 to 9 inches). The samples were 

analyzed by gravimetric analysis for the thoracic fraction of metalworking fluid particulates 

per NIOSH Method 5524 [NIOSH 2015]. After the filter was gravimetrically weighed, a 

ternary solvent blend was used to extract the metalworking fluid fraction from each sample.

Endotoxin Sampling and Analysis

Air samples were collected by using an endotoxin-free three-piece 37-millimeter closedface cassette, preloaded with 0.45-micrometer-pore-size polycarbonate filters. Samples were 

collected with AirCheck2000® personal air-sampling pumps calibrated at 2 liters per minute. 

Each pump was calibrated before and after use. Samples were analyzed for endotoxin content 

with the kinetic-chromogenic procedure using the limulus amebocyte lysate assay [Cambrex 

2005]. For these analyses, one EU was equivalent to 0.053 nanograms of endotoxin. The 

limit of detection was 0.50 EU per sample.

Viable Microbe Sampling and Analysis

We collected bulk metalworking fluid samples using a sterile pipette to fill 4-ounce sterile 

bottles, leaving at least 1 inch of headspace. These samples were kept on ice and shipped 

within 1 day to the laboratory for analysis. Each sample was concentrated by a 30-minute 

centrifuge, and excess fluid was poured off. The concentrate was vortexed for 1 minute and 

then plated to the appropriate media.

For aerobic bacteria, the media consisted of tryptic soy agar with polysorbate 80 and lecithin 

and buffered charcoal yeast extract. Plates were incubated at 23 ± 2 degrees Celsius (C) 

for 5 to 7 days and read daily. The media for fungi were yeast malt extract, inhibitory mold 

agar with gentamicin and chloramphenicol, and buffered charcoal yeast extract. Plates were 

incubated at 23°C ± 2°C for 10 days as needed. Each plate was read on day 3 to see if it 

was overgrown and then read again on day 5 or 7 and day 10. The media for mycobacteria 

consisted of buffered charcoal yeast extract, Middlebrook 7H10, and Mitchison 7H11S. 

Plates and broth were incubated at 32°C ± 2°C in 7%–10% CO2 for 4 weeks. Cultures were 

read at 3–5 days and 7 days. If specimens were overgrown, additional dilutions were made. 

Broths were Ziehl-Neelsen-stained at 2–3 weeks and 4 weeks [MSI 2011].
Health Hazard Evaluation Report 2014-0050-3234 Page 19

Volatile Organic Compound Sampling and Analysis

Area air was sampled for VOCs with thermal desorption tubes attached to SKC Inc. Pocket 

Pumps® calibrated at 100 cubic centimeters per minute. The thermal desorption tubes 

contained three beds of sorbent material: (1) 90 milligrams of CarbopackTM Y, (2) 115 

milligrams of Carbopack B, and (3) 150 milligrams CarboxenTM. After sampling, the thermal 

desorption tubes were stored in a cooler and then qualitatively analyzed for VOCs according 

to NIOSH Method 2549 [NIOSH 2015].

Microbial Diversity in Air and Metalworking Fluids 

Sampling and Analysis

Media Sampling for Microbial Diversity Analysis

We collected aerosols using a two-stage sampler with two cyclones depositing into 

microcentrifuge tubes and onto a mixed cellulose ester filter. We used AirCheck2000® 

personal air sampling pumps calibrated at 2 liters per minute. Each pump was calibrated 

before and after use. The bioaerosol samplers allowed for the collection of particles 

across three size fractions: ≥ 4.1 micrometers, 1.0–4.1 micrometers, and < 1.0 micrometer 

aerodynamic diameter. The three size cut samples taken with each bioaerosol sampler were 

aggregated for genomic DNA analysis. 

We collected bulk metalworking fluid samples using a sterile pipette to fill a 4-ounce sterile 

bottle. These samples were kept on ice and shipped within 1 day to the laboratory for analysis.

Genomic DNA Extraction from Sample Media for Analysis

Air and metalworking fluid samples were processed separately for fungal and bacterial DNA

extraction with use of the Roche High Pure polymerase chain reaction (PCR) template kit, 

as previously described [Rittenour et al. 2012; Rittenour et al. 2014]. Metalworking fluid 

samples, including internal controls, were centrifuged at 5,000 revolutions per minute for 

10 minutes at 4°C. The supernatant fluid was then decanted, and the pellet was resuspended 

in 1 milliliter (mL) filter-sterilized (0.45 micrometer [μm]) phosphate buffered saline (pH 

7.4), transferred to a 1.5-mL polypropylene microcentrifuge tube, and centrifuged at 14,000 

revolutions per minute for 5 minutes. The supernatant fluid was then decanted and the pellet 

was resuspended in 1 mL phosphate buffered saline and centrifuged for a further 

5 minutes, at 14,000 revolutions per minute. The supernatant fluid was decanted and 

the pellet resuspended in 500 microliter (μL) phosphate buffered saline; 20 μL of each 

metalworking fluid sample was added to a 2-mL bead-beater tube containing 300 mg glass 

beads (212–300 μm). The High Pure PCR kit lysis buffer was then added to each tube 

(330 μL) and placed in a BioSpec Products bead beater for 30 seconds at high speed. The 

tubes were centrifuged for 1 minute at 20,000 x g, and the supernatant was transferred to a 

1.5-mL microcentrifuge tube and incubated with 25 μL Cell Lytic B lysis reagent for 

15 minutes at 37°C. The kit’s binding buffer (200 μL) and proteinase K (40 μL) were then 

added, and the solution was incubated at 70°C for 10 minutes. The sample was washed and 

eluted in 100 μL according to the manufacturer’s instructions. 
Page 20 Health Hazard Evaluation Report 2014-0050-3234

For air samples, including field blank and internal controls, each stage from the NIOSH 

BC251 air sampler was combined prior to DNA extraction. The after filter was sectioned 

into six pieces with a scalpel using aseptic methods. These pieces were placed into a 2 mL 

bead-beater tube containing 300 mg glass beads as described above. The tubes were placed 

in liquid nitrogen for 30 seconds and processed in a bead beater for 30 seconds. This process 

was repeated three times. The High Pure PCR Template kit lysis buffer (650 μL) was then 

sequentially added to the first and second stage tubes and vortexed in order to collect the 

fungal and bacterial particles from the samples. The lysis buffer was added to the 2 mL beadbeater tube containing the macerated filter material. These tubes were processed with a bead 

beater for 30 seconds and then centrifuged for 1 minute at 20,000 x g. The supernatant was 

collected and incubated with 40 μL Sigma Aldrich Cell Lytic B lysis reagent for 15 minutes 

at 37°C. The sample was mixed with the kit’s binding buffer (400 μL) and proteinase K 

(40 μL) and incubated at 70°C for 10 minutes. The sample was then washed and eluted in 

100 μL as recommended by the manufacturer.

Fungal ITS and Bacterial 16S rDNA Amplification, Cloning, and Sanger 

Sequencing

Fungal ribosomal deoxyribonucleic acid (rDNA) was targeted for PCR amplification as 

previously described [Rittenour et al. 2012; Rittenour et al. 2014]. Briefly, fungal rDNA 

sequences were amplified with the primer pair Fun18Sf (TTGCTCTTCAACGAGGAAT) 

and ITS4 (TCCTCCGCTTATTGATATGC). Fungal internal transcribed spacer-1 (ITS1) and 

ITS2 regions were then amplified with Platinum Taq DNA polymerase (Invitrogen) according 

to the methods previously described [Rittenour et al. 2012; Rittenour et al. 2014]. For fungal 

amplification, 5 replicate PCR reactions (50 μL) were run for each sample by using 5 μL of 

DNA template. These replicates were then combined, and the rDNA amplicons were purified 

with a Qiagen PCR purification kit, according to the manufacturer’s instructions. Purified 

product (8 μL) was then run on a 1% agarose gel containing 1 microgram per milliliter 

(μg/mL) ethidium bromide and examined for amplicons with ultraviolet light.

Bacterial 16S rDNA sequences were amplified with use of the highly conserved primer 

pair p8FPL (AGTTTGATCCTGGCTCAG) and p806R (GGACTACCAGGGTATCTAAT) 

[McCabe et al. 1999]. Bacterial 16S rRNA genes were amplified with Invitrogen Platinum 

Taq DNA polymerase by a modified method of McCabe et al. [1999]. The PCR conditions 

included initial denaturation at 95°C for 4 minutes, followed by 33 cycles of denaturation 

at 94°C for 1 minute, annealing at 55°C for 1 minute, extension at 72°C for 2 minutes, 

and completion with a final extension at 72°C for 10 minutes. Three 50-μL replicate PCR 

reactions were run for each sample, with use of 5 μL of DNA template. These replicates 

were then combined and the rDNA amplicons were purified with a Qiagen PCR purification 

kit according to the manufacturer’s instructions. Purified product (8 μL) was then run on 

a 1% agarose gel containing 1 μg/mL ethidium bromide and examined for amplicons with 

ultraviolet light.

On the basis of the low yield of fungal DNA captured during extraction, bacteria were 

selected for further cloning and sequencing. Bacterial amplicons were separately cloned 

into the pDRIVE vector using a Qiagen PCR cloning kit. Clone libraries were generated by 
Health Hazard Evaluation Report 2014-0050-3234 Page 21

transforming cloned plasmids into chemically competent Escherichia coli cells as previously 

described [Rittenour et al. 2012; Rittenour et al. 2014]. Positive colonies (as determined 

colorimetrically by the inactivation of the lacZ gene) were selected and cultured for 

16 hours at 37°C in liquid Luria-Bertani medium containing 100 μg/mL ampicillin. Resultant 

cells were centrifuged at 1,800 x g and the pellet was resuspended in 200 μL of 15% glycerol 

and sent to Genewiz Inc. for Sanger sequencing of the bacterial 16S insert. Inserts were 

sequenced in both directions, allowing for sequence analysis of the 16S region. 

Sequencing results were downloaded as “.ab1” chromatogram files from Genewiz Inc. Vector 

sequence data were trimmed and forward and reverse sequences were assembled using 

Biomatters Geneious R7 Software. Then we sequenced the DNA to identify which varieties 

of bacteria were present in the air. Sequence data were then clustered into OTUs with 

MOTHUR software version 1.32.1 using a 97% similarity cutoff as described in previous 

publications [Rittenour et al. 2012; Rittenour et al. 2014]. Sequences representative of each 

OTU were then used in a Basic Local Alignment Search Tool (BLAST) search against the 

NCBI database [Schloss et al. 2009].
Page 22 Health Hazard Evaluation Report 2014-0050-3234

Appendix B: Occupational Exposure Limits and 

Health Effects

NIOSH investigators refer to mandatory (legally enforceable) and recommended OELs for 

chemical, physical, and biological agents when evaluating workplace hazards. OELs have 

been developed by federal agencies and safety and health organizations to prevent adverse 

health effects from workplace exposures. Generally, OELs suggest levels of exposure that 

most employees may be exposed to for up to 10 hours per day, 40 hours per week, for a 

working lifetime, without experiencing adverse health effects. However, not all employees 

will be protected if their exposures are maintained below these levels. Some may have 

adverse health effects because of individual susceptibility, a pre-existing medical condition, 

or a hypersensitivity (allergy). In addition, some hazardous substances act in combination 

with other exposures, with the general environment, or with medications or personal habits of 

the employee to produce adverse health effects. Most OELs address airborne exposures, but 

some substances can be absorbed directly through the skin and mucous membranes.

Most OELs are expressed as a TWA exposure. A TWA refers to the average exposure during 

a normal 8- to 10-hour workday. Some chemical substances and physical agents have 

recommended short-term exposure limit or ceiling values. Unless otherwise noted, the shortterm exposure limit is a 15-minute TWA exposure. It should not be exceeded at any time 

during a workday. A ceiling limit should not be exceeded at any time.

In the United States, OELs have been established by federal agencies, professional 

organizations, state and local governments, and other entities. Some OELs are legally 

enforceable limits; others are recommendations. 

● The U.S. Department of Labor OSHA permissible exposure limits (29 CFR 1910 

[general industry]; 29 CFR 1926 [construction industry]; and 29 CFR 1917 [maritime 

industry]) are legal limits. These limits are enforceable in workplaces covered under the 

Occupational Safety and Health Act of 1970. 

● NIOSH RELs are recommendations based on a critical review of the scientific and technical 

information and the adequacy of methods to identify and control the hazard. NIOSH 

RELs are published in the NIOSH Pocket Guide to Chemical Hazards [NIOSH 2010]. 

NIOSH also recommends risk management practices (e.g., engineering controls, safe work 

practices, employee education/training, personal protective equipment, and exposure and 

medical monitoring) to minimize the risk of exposure and adverse health effects.

● Other OELs commonly used and cited in the United States include the threshold 

limit values, which are recommended by the American Conference of Governmental 

Industrial Hygienists, a professional organization, and the workplace environmental 

exposure levels, which are recommended by the American Industrial Hygiene 

Association, another professional organization. The threshold limit values and 

workplace environmental exposure levels are developed by committee members of 

these associations from a review of the published, peer-reviewed literature. These OELs 

are not consensus standards. Threshold limit values are considered voluntary exposure 
Health Hazard Evaluation Report 2014-0050-3234 Page 23

guidelines for use by industrial hygienists and others trained in this discipline “to assist 

in the control of health hazards” [ACGIH 2015]. Workplace environmental exposure 

levels have been established for some chemicals “when no other legal or authoritative 

limits exist” [AIHA 2014].

Outside the United States, OELs have been established by various agencies and organizations 

and include legal and recommended limits. The Institut für Arbeitsschutz der Deutschen 

Gesetzlichen Unfallversicherung (Institute for Occupational Safety and Health of the German 

Social Accident Insurance) maintains a database of international OELs from European 

Union member states, Canada (Québec), Japan, Switzerland, and the United States. The 

database, available at http://www.dguv.de/ifa/Gefahrstoffdatenbanken/GESTIS-InternationaleGrenzwerte-für-chemische-Substanzen-limit-values-for-chemical-agents/index-2.jsp, contains 

international limits for more than 1,500 hazardous substances and is updated periodically. 

OSHA requires an employer to furnish employees a place of employment free from 

recognized hazards that cause or are likely to cause death or serious physical harm 

[Occupational Safety and Health Act of 1970 (Public Law 91–596, sec. 5(a)(1))]. This is 

true in the absence of a specific OEL. It also is important to keep in mind that OELs may not 

reflect current health-based information.

When multiple OELs exist for a substance or agent, NIOSH investigators generally 

encourage employers to use the lowest OEL when making risk assessment and risk 

management decisions. NIOSH investigators also encourage use of the hierarchy of controls 

approach to eliminate or minimize workplace hazards. This includes, in order of preference, 

the use of (1) substitution or elimination of the hazardous agent, (2) engineering controls 

(e.g., local exhaust ventilation, process enclosure, dilution ventilation), (3) administrative 

controls (e.g., limiting time of exposure, employee training, work practice changes, medical 

surveillance), and (4) personal protective equipment (e.g., respiratory protection, gloves, 

eye protection, hearing protection). Control banding, a qualitative risk assessment and risk 

management tool, is a complementary approach to protecting employee health. Control 

banding focuses on how broad categories of risk should be managed. Information on control 

banding is available at http://www.cdc.gov/niosh/topics/ctrlbanding/. This approach can be 

applied in situations where OELs have not been established or can be used to supplement 

existing OELs.

Below we provide the OELs and surface contamination limits for the compounds we measured, 

as well as a discussion of the potential health effects from exposure to these compounds.

Metalworking Fluids

NIOSH recommends that exposures to metalworking fluid aerosols be limited to 

0.4 mg/m3 for the thoracic particulate mass, as a TWA concentration for up to 10 hours per 

day during a 40-hour workweek [NIOSH 1998]. The NIOSH REL is intended to prevent or 

greatly reduce respiratory disorders associated with metalworking fluid exposure. In addition, 

limiting dermal (skin) exposure is critical to preventing allergic and irritant disorders 

related to metalworking fluid exposure. NIOSH recommends that all employees exposed 
Page 24 Health Hazard Evaluation Report 2014-0050-3234

to metalworking fluids at over half the REL receive medical monitoring, and all employees 

with exposure to metalworking fluid may benefit from medical monitoring [NIOSH 1998]. 

Supervision of the medical monitoring program should be done by a physician or other health 

professional with expertise in the identification and management of metalworking fluid-related 

respiratory conditions and skin diseases. Contaminated water in metalworking fluids may also 

contain fungi. Some fungi may infect susceptible hosts, such as immune compromised persons, 

and exposure to some fungi may result in adverse health effects such as hypersensitivity 

pneumonitis, allergic sensitization, and asthma. At this time, health data are insufficient to 

recommend a specific limit for fungal contamination in metalworking fluids.
Health Hazard Evaluation Report 2014-0050-3234 Page 25

Appendix C: Mycotoxins

Fungi can be found both indoors and outdoors. Fungi can cause adverse health effects in 

humans through three processes: (1) allergy, (2) infection, and (3) toxicity. About 40% of 

the population are atopic and express high levels of allergic antibodies to inhaled allergens. 

Of these, 25%, or 10% of the population, have allergic antibodies to common inhaled fungi 

[Horner et al. 1995]. While indoor fungi are well-recognized allergens, outdoor molds are 

generally more important [ACOEM 2011].

Most fungi are generally not pathogenic to healthy humans. Exposure to fungi indoors 

is generally not a specific risk factor for fungal infections. Exceptions include fungi that 

can cause superficial infections on the skin or mucosal surfaces of healthy people. These 

fungi include Trichophyton, Epidermophyton, and Microsporum species, which can cause 

infections of the epidermis and dermis. Other exceptions include dimorphic fungal pathogens 

such as Blastomyces, Coccidioides, and Histoplasma, which have areas of endemnicity and 

are not normally found growing in residential or work environments such as this facility 

[ACOEM 2011]. 

Some species of fungi are capable of producing toxins, known as mycotoxins. Some 

mycotoxins such as penicillin and cyclosporine have a valuable clinical use. Mycotoxins 

are produced by a number of fungal genera, including Alternaria, Aspergillus, Claviceps, 

Fusarium, Stachybotrys, and Penicillium [Marin et al. 2013]. Most described human 

poisonings by mycotoxins have involved the eating of moldy foods and inhalation exposures 

of agricultural workers to spoiled grain products containing high concentrations of fungi and 

bacteria [Ciegler and Bennett 1980; Pohland 1993; Wu et al. 2014].

Critical reviews of the scientific literature have determined that there is currently no 

conclusive evidence of an association between mycotoxin exposure in the indoor 

environment and human illness [Menzies et al. 1997; Fung et al. 1998; Robbins et al. 2000; 

Sudakin 2000; Page and Trout 2001; Terr 2001]. No causal relationship has been established 

between health complaints and indoor exposures to specific molds such as Stachybotrys 

chartarum [ACOEM 2011].

Although commercially available and offered at many different sites, mycotoxin tests are 

considered to be “nonstandard tests.” Uncertainty exists as to how to interpret the results of 

these biologic tests for mycotoxins. These toxins can be found at different levels in the blood 

and urine of healthy people who do not report adverse health symptoms. The meaning of a 

“high level” versus a “low level” is unknown. These tests, when repeated, cannot be depended 

upon to give consistent results. Therefore, these tests are not considered to be valid or reliable.

Biologic tests for mycotoxins are not approved by the Food and Drug Administration 

(FDA). Although testing may be done at a laboratory certified under the Clinical Laboratory 

Improvement Amendments (CLIA), the tests themselves are not CLIA certified. Therefore, 

testing in a CLIA-certified laboratory is not necessarily approved by the FDA, and clinicians 

do not necessarily use the test results appropriately for diagnosis. CLIA certification of a 

laboratory indicates that the laboratory meets a set of basic quality standards. It is important 
Page 26 Health Hazard Evaluation Report 2014-0050-3234

to note, however, that the CLIA program does not address the clinical validity of a specific 

test (i.e., the accuracy with which the test identifies, measures, or predicts the presence or 

absence of a clinical condition in a patient). FDA clearance/approval of a test, on the other 

hand, provides assurance that the test itself has adequate analytical and clinical validation and 

is safe and effective [Nelson et al. 2014].
Health Hazard Evaluation Report 2014-0050-3234 Page 27

Appendix D. Bacterial Species that Produce Pyrazines Table D1. Bacterial species that produce pyrazines Organism Family Order Class Phylum Pyrazine(s) Chondromyces crocatus Polyangiaceae Myxococcales Deltaproteobacteria Proteobacteria Hydroxyalkylmethoxypyrazines, 3,5-MDMP, 3,6-MDMP [Chatonnet et al. 2010] Serratia odorifera Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria 3,5-MDMP [Chatonnet et al. 2010] Rhizobium excellensis Rhizobiaceae Rhizobiales Alphaproteobacteria Proteobacteria 3,5-MDMP[Chatonnet et al. 2010] Pseudomonas perolens Pseudomonadaceae Pseudomonadales Gammaproteobacteria Proteobacteria 2-methoxy-3-isopropylpyrazine, 2-sec-butyl-3- methoxypyrazine [Chatonnet et al. 2010] Serratia spp. Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria 2-methoxy-3-isopropylpyrazine, 2-sec-butyl-3- methoxypyrazine [Chatonnet et al. 2010] Cedecea spp. Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria 2-methoxy-3-isopropylpyrazine, 2-methoxy-3-(1-methylpropyl)-pyrazine [Chatonnet et al. 2010] Novosphingobium subarcticum Sphingomonadaceae Sphingomonadales Alphaproteobacteria Proteobacteria Detected in 3,5-MDMP tainted corks [Prat et al. 2009] Sphingobacterium spp. Sphingobacteriaceae Sphingobacteriales Sphingobacteria Bacteroidetes Acinetobacter lwoffi Moraxellaceae Pseudomonadales Gammaproteobacteria Proteobacteria Pseudomonas spp. Pseudomonadaceae Pseudomonadales Gammaproteobacteria Proteobacteria Several methylpyrazines [Bañeras et al. 2013] Pseudomonas taetrolens Pseudomonadaceae Pseudomonadales Gammaproteobacteria Proteobacteria 2-methoxy-3-isopropylpyrazine [Chatonnet et al. 2010] Bacillus cereus Bacillaceae Bacillales Bacilli Firmicutes Tetramethylpyrazine [Seitz 1994] Bacillus subtilis Bacillaceae Bacillales Bacilli Firmicutes 2,5-Dimethylpyrazine, Trimethylpyrazine, Tetramethylpyrazine, 2-ethyl-5-methylpyrazine, 2-methylpyrazine, 2-ethylpyrazine, 2,3-dimethylpyrazine [Larroche et al. 1999] Corynebacterium glutamicum Corynebacteriaceae Actinomycetales Actinobacteria Actinobacteria Tetramethylpyrazine [Seitz 1994] Halomonas venusta Halomonadaceae Oceanospirillales Gammaproteobacteria Proteobacteria 2-methoxy-3-(1-methylpropyl)-pyrazine [Bungert et al. 2001] Paenibacillus polymyxa Paenibacillaceae Bacillales Bacilli Firmicutes Several isopropylpyrazines [Beck et al. 2003] Serratia ficara Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria Several methylpyrazines [Gallois and Grimont 1985] Serratia rubidae Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria Cedecea davisae Enterobacteriaceae Enterobacteriales Gammaproteobacteria Proteobacteria
Page 28 Health Hazard Evaluation Report 2014-0050-3234

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Page 32 Health Hazard Evaluation Report 2014-0050-3234

Keywords: North American Industry Classification System 336413 (Other Aircraft 

Parts and Auxiliary Equipment Manufacturing), Pennsylvania, odor, VOCs, chemical, 

methoxypyrazine, metalworking fluid, MWF, mycotoxin, indoor environmental quality, IEQ, 

pyrazines, bacteria
Health Hazard Evaluation Report 2014-0050-3234 Page 33

The Health Hazard Evaluation Program investigates possible health hazards in the workplace 

under the authority of the Occupational Safety and Health Act of 1970 (29 U.S.C. § 669(a)

(6)). The Health Hazard Evaluation Program also provides, upon request, technical assistance 

to federal, state, and local agencies to investigate occupational health hazards and to prevent 

occupational disease or injury. Regulations guiding the Program can be found in Title 42, Code 

of Federal Regulations, Part 85; Requests for Health Hazard Evaluations (42 CFR Part 85).

Disclaimer

The recommendations in this report are made on the basis of the findings at the workplace 

evaluated and may not be applicable to other workplaces.

Mention of any company or product in this report does not constitute endorsement by NIOSH.

Citations to Web sites external to NIOSH do not constitute NIOSH endorsement of the 

sponsoring organizations or their programs or products. NIOSH is not responsible for the 

content of these Web sites. All Web addresses referenced in this document were accessible as of 

the publication date.

Acknowledgments

Analytical Support: Jennifer Roberts, Fariba Nourian, Robert Streicher, MSI Laboratories, 

Bureau Veritas North America

Desktop Publisher: Shawna Watts 

Editor: Ellen Galloway 

Logistics: Donnie Booher, Kevin Moore

Medical Field Assistance: Judith Eisenberg

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local health department and the Occupational Safety and Health Administration Regional Office 

have also received a copy. This report is not copyrighted and may be freely reproduced. 

This report is available at http://www.cdc.gov/niosh/hhe/reports/pdfs/2014-0050-3234.pdf.

Recommended citation for this report:

NIOSH [2015]. Health hazard evaluation report: evaluation of an unpleasant odor at 

an aircraft ejection seat manufacturer. By Broadwater K, de Perio MA, Brueck SE, 

Burton NC, Lemons AR, Green BJ. Cincinnati, OH: U.S. Department of Health and 

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

Occupational Safety and Health, NIOSH HHE Report No. 2014-0050-3234.
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