Evaluation of 

Potential Exposures 

during Composite 

Grinding at an Aircraft 

Manufacturing Plant

Srinivas Durgam, MSPH, MSChE, CIH

Marie A. de Perio, MD

Health Hazard Evaluation Report

HETA 2007-0344-3104

Cessna Aircraft Company

Wichita, Kansas

March 2010

Department of Health and Human Services

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

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

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

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

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

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

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

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2007-0344-3104 Page i

Appendix A

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

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

Summary ............................................................................iv

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

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

Results.................................................................................3

Discussion ...........................................................................7

Conclusions.........................................................................9

Recommendations...............................................................9

References ........................................................................11

Contents

Acknowledgments and Availability of Report.....................17

Methods.............................................................................13

Occupational Exposure Limits & Health Effects ................14

Acknowledgments

Appendix B
Page ii Health Hazard Evaluation Report 2007-0344-3104

μm Micrometer 

ACGIH® American Conference of Governmental Industrial Hygienists

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

BADGE Diglycidyl ether of bisphenol-A

CFR Code of Federal Regulations

CO Carbon monoxide

CO2 Carbon dioxide

D039 Department 039

D133 Department 133

GA General area

HHE Health hazard evaluation

MDC Minimum detectable concentration 

mg/m3 Milligrams per cubic meter

MQC Minimum quantifiable concentration 

mm Millimeter

MSDS Material safety data sheet

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PBZ Personal breathing zone

PEL Permissible exposure limit

PPE Personal protective equipment

ppm Parts per million

REL Recommended exposure limit

RH Relative humidity

SMA Sheet metal assembler

STEL Short term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

WEEL Workplace environmental exposure level

Abbreviations
Health Hazard Evaluation Report 2007-0344-3104 Page iii

Highlights of the

NIOSH Health

Hazard Evaluation

The National Institute 

for Occupational Safety 

and Health (NIOSH) 

received a confidential 

employee request for a 

health hazard evaluation 

at Cessna Aircraft 

Company in Wichita, 

Kansas. The requestors 

were concerned about 

exposure to paint 

and sealants, carbon 

monoxide, and dust 

generated during 

grinding of composite 

and metal parts. Reported 

health effects included 

headaches, dizziness, 

fatigue, and abdominal 

pain. 

What NIOSH Did

● We evaluated the facility on January 23–24, 2008.

● We looked at work processes and practices in Departments 

039 and 133.

● We collected air samples for total dust, respirable dust, and 

carbon monoxide. We also analyzed the total dust air samples 

for metals.

● We determined the particle size distribution of the dust 

generated during grinding.

● We talked to employees about health symptoms related to 

work.

● We reviewed air sampling records, maintenance records for a 

downdraft table, material safety data sheets, and injury and 

illness records. 

What NIOSH Found

● Air sampling results for total dust, respirable dust, 

metals, and carbon monoxide were below the applicable 

occupational exposure limits.

● Particles generated during grinding were mainly in the size 

range that can be inhaled deep into the lungs (below 5 

micrometers).

● Exposure to paints and sealants was minimal and not likely 

to be a hazard.

● One employee reported being diagnosed with asthma since 

working at Cessna, and three of four employees with preexisting asthma said their asthma was worse at work. 

● Three employees reported skin problems related to work.

● Two employees reported headaches but none of the 

interviewed employees reported dizziness, fatigue, or 

abdominal pain.

● Some employees had facial hair that interfered with their 

respirator seal.

What Managers Can Do

● Require employees to use downdraft tables when grinding 

composite materials. 

● Provide shrouded grinding and buffing tools to employees 

when tasks prevent the use of downdraft tables.

● Make sure that respirators are used correctly. 

● Encourage employees to report all work-related health 

concerns to the onsite medical department. 

What Employees Can Do

● Use a downdraft table when grinding composite materials. 

This will further reduce dust exposure. 

● Wear respirators properly. Be clean shaven to ensure a good 

seal.

● Report all work-related health concerns to the onsite medical 

clinic.
Page iv Health Hazard Evaluation Report 2007-0344-3104

Summary

NIOSH received a 

request to evaluate 

employee exposures in 

two departments at the 

Cessna Prospect facility. 

We found that employee 

exposures to total dust, 

respirable dust, metals, 

and CO were below the 

OELs. However, some 

employees noted either 

onset of asthma or 

worsening of pre-existing 

asthma at work. Despite 

low levels of total and 

respirable dust and 

metals, it is possible that 

the reported respiratory 

symptoms are work 

related. We recommend 

that employees use 

downdraft tables and 

shrouded grinding 

tools when grinding on 

composite materials to 

further reduce exposures. 

We also encourage 

employees to report 

all work-related health 

concerns to the onsite 

medical clinic.

NIOSH received a confidential request from employees for an 

HHE at the Prospect facility of Cessna Aircraft Company (Cessna) 

in Wichita, Kansas. The requestors were concerned about adverse 

health effects from exposure to paint and sealants, CO, and dust 

generated during grinding of composite and metal parts in D039 

and D133. Health effects noted in the request were headaches, 

dizziness, fatigue, and abdominal pain.

We evaluated the facility on January 23–24, 2008, to learn more 

about the manufacturing process. We observed work practices; 

evaluated employee exposure to total dust, respirable dust, and 

CO; and interviewed employees in D039 and D133 about their 

health. We also interviewed Cessna’s Health Services manager. 

We reviewed the OSHA Form 300 Log of Work-related Injuries 

and Illnesses from the years 2005–2007 and company air sampling 

reports for D039 and D133 from 2002–2007. We also looked at 

MSDSs and the maintenance chart for the downdraft table in 

D039. 

Three of four employees in D039 and D133 with pre-existing 

asthma reported worsening of their asthma at work. One employee 

reported being diagnosed with asthma since beginning work at 

Cessna. Three employees reported skin rashes, and two employees 

reported headaches. None of the interviewed employees reported 

dizziness, fatigue, or abdominal pain. Our air sampling results 

indicated that employees’ exposures to total dust, respirable dust, 

and metals were below the NIOSH RELs, OSHA PELs, and 

ACGIH TLVs. Air sampling results for CO indicated that the air 

concentrations were below all applicable OELs. However, dust 

generated from grinding composite materials can contain reactive 

components that can cause health effects at levels far below the 

applicable OELs. Despite low levels of total and respirable dust and 

metals, it is possible that the reported respiratory symptoms are 

work related.

To further reduce exposure to dust, we recommend that employees 

use downdraft tables when grinding on composite materials. 

Engineering controls such as shrouded grinding tools should also 

be provided to employees. Employees should wear respirators 

correctly, including being clean shaven to have a good seal. We also 

encourage employees to report all work-related health concerns to 

the onsite medical clinic.

Keywords: NAICS 336411 (Aircraft Manufacturing), composite 

material, grinding, epoxy, BADGE, asthma, carbon monoxide
Health Hazard Evaluation Report 2007-0344-3104 Page 1

Introduction

In August 2007, NIOSH received a confidential request from 

employees for an HHE at the Prospect facility of Cessna Aircraft 

Company (Cessna) in Wichita, Kansas. The requestors were 

concerned about potential adverse health effects from exposure 

to paint and sealants, CO, and dust generated during grinding 

of composite and metal parts in D039 and D133. Health effects 

noted in the request were headaches, dizziness, fatigue, and 

abdominal pain. We visited the Cessna facility from January 

23–24, 2008, to learn more about the manufacturing process; 

observe work practices; review pertinent records; evaluate employee 

exposure to total dust, respirable dust, metals, and CO; and 

interview employees in D039 and D133 about their health. 

Facility and Process Description 

Cessna manufactures a variety of commercial aircraft and employs 

around 15,000 people at its Wichita, Kansas, site. The site has 

numerous facilities that manufacture parts for different aircraft 

models. Various phases of the aircraft manufacturing operations 

are housed in different buildings on the site. 

The Prospect facility has 348 employees, of whom 16 work in D039 

and D133. These employees work 8-hour shifts. The composite 

parts used in D039 and D133 are manufactured in a different 

building and use a woven fiberglass material pre-impregnated 

with epoxy resins, filler, and other suitable hardening agents. 

The raw woven fiberglass material arrives at Cessna in rolled-up 

bundles that are laid out and cut to specification by an automated 

machine. The cut fiberglass mat is then laid out on premade molds 

for various aircraft parts and heated in large curing ovens. In the 

curing process, the epoxy resin in the woven material hardens 

into the shape of the aircraft part when heat is applied. The cured 

composite part is then removed from the mold, and the excess 

material is trimmed with hand held grinding machines. These 

parts are then painted with a spray gun, air dried, and sent to 

various departments, including D039 and D133, for machining. 

In D039 and D133, painted and cured composite parts are ground 

to the exact dimensions specified for the parts. Metal parts are 

riveted together, and employees use a paint brush to touch up the 

parts with paint and a corrosion inhibiting sealant such as alodine 

before sending them to a different department. Propane powered 

forklift trucks, which can generate CO, are used in the facility to 

move airplane parts. 
Page 2 Health Hazard Evaluation Report 2007-0344-3104

Introduction 

(continued)

Assessment

In D039, employees working with composite materials can 

perform grinding for 6–8 hours during their work shift. D039 

has a downdraft table that employees use when they are grinding 

on larger composite material parts. We observed that employees 

grinding smaller composite parts conducted these tasks at their 

workstations or used a step stool instead of using the downdraft 

table. Exhaust ventilation was not available at employee 

workstations. Employees wore Tyvek® suits, elastomeric half 

mask air purifying respirators with P100 cartridges, safety glasses 

or face shields, ear muffs, and cotton gloves when grinding 

composite parts. Employees were medically cleared and fit tested 

for respirators, but the use of respiratory protection in these 

departments was voluntary. 

Cessna has three onsite medical clinics with a full time physician, 

a nurse practitioner, and six registered nurses. The company 

has a health and safety committee that includes employee and 

management representatives.

During our site visit, which took place from January 23–24, 2008, 

we met with employer and employee representatives to discuss 

the HHE request. We observed work processes, employee work 

practices, and workplace conditions. We privately interviewed 

most of the employees working in D039 and D133. The interviews 

focused on job history, overall health, and work-related symptoms. 

We also interviewed Cessna’s Health Services manager. We 

reviewed the OSHA Logs for years 2005–2007, the company’s air 

sampling reports pertaining to D039 and D133 from 2002–2007, 

MSDSs, and the D039 downdraft table maintenance chart. 

The dust generated during grinding of composite materials was 

one of the requestors’ primary concerns; therefore, we evaluated 

exposures of SMAs who worked with composite materials and 

metal parts in D039 and D133. We collected seven PBZ and three 

GA air samples for respirable dust and five PBZ and four GA air 

samples for total dust and metals during the last half of the work 

shift on January 23, 2008, and for the full work shift on January 

24, 2008. Respirable dust and total dust air samples were analyzed 

gravimetrically. After gravimetric analysis, the total dust air samples 

were also analyzed for metals. In addition, we characterized the 

particle size of dust generated by grinding (Figure 1) with an ARTI 

HHPC-6 (ART Instruments, Inc., Grant Pass, Oregon), a handheld 
Health Hazard Evaluation Report 2007-0344-3104 Page 3

Assessment (continued) optical particle counter that was held in the breathing zone of the 

employee during sample collection. 

We noted the use of two propane gas powered forklifts and 

measured CO, a combustion product, in the high forklift traffic 

areas of D133 and outdoors with a direct reading instrument (TSI 

Q-TrakTM, Shoreview, Minnesota). The instrument also provided 

temperature and relative humidity measurements.

Details on the methods used in this evaluation for total dust, 

respirable dust, and metals are explained in Appendix A. The 

OELs and potential health effects for exposure to total and 

respirable dust and CO are discussed in Appendix B.

PBZ and GA air sampling results for total dust along with the 

applicable OELs are presented in Tables 1 and 2. Although air 

samples were only collected for approximately half of the work 

shift on January 23, 2008, the TWA results are considered 

representative of full-shift exposures.

The total dust PBZ air sample concentrations obtained during our 

sampling ranged up to 0.28 mg/m3 (Table 1). All concentrations 

were below the OSHA PEL of 15 mg/m3

 and ACGIH TLV of 

10 mg/m3. The GA total dust concentrations ranged from 

0.11–0.29 mg/m3 (Table 2). The five PBZ total dust air samples 

were also analyzed for individual elements and showed the 

presence of metals such as aluminum, cadmium, chromium, 

copper, and manganese. However, the concentrations of the metals 

were 0.001%–0.1% of their respective OELs. 

Figure 1. Employee using a handheld 

grinder to grind composite material.

Results

Table 1. PBZ air sample results for total dust (January 23–24, 2008)

Date Job Title Department 

Number

Sampling Time Air Concentration

(minutes) (mg/m3

)

1/23/2008

SMA D133 201 0.28

SMA D039 285 0.17

SMA D039 236 (0.17)*

1/24/2008 SMA D133 500 0.26

SMA D039 469 0.25

 OSHA PEL 15

 ACGIH TLV 10†

*Values in parentheses indicate a concentration between the MDC and the MQC.

†Inhalable fraction
Page 4 Health Hazard Evaluation Report 2007-0344-3104

Results (continued)

The ARTI HHPC-6 particle counter counts particles in size ranges 

of 0.3, 0.5, 1, 3, 5, and > 10 μm. The particle count result showed 

that on average, 95% of the particles generated during grinding 

were less than 5 μm in diameter, which is in the respirable range. 

The CO, temperature, and RH measurements in D133 are 

summarized in Table 4. The outdoor CO concentration was 

0 ppm, and the indoor CO measurements ranged from 0–13 ppm 

on January 23, 2008, and from 0–2 ppm on January 24, 2008. 

These concentrations are well below the NIOSH recommended 

ceiling limit of 200 ppm [NIOSH 2005]. Additionally, the mean 

The respirable dust PBZ air sample concentrations ranged up to 

0.29 mg/m3 (Table 3) and were below the OSHA PEL of 5 mg/m3

and the ACGIH TLV of 3 mg/m3. The three GA respirable dust 

sample concentrations were below the MDCs.

Table 2. GA air sample results for total dust (January 23–24, 2008)

Date Sample Location Department 

Number

Sampling Time Air Concentration

(minutes) (mg/m3)

1/23/2008 Post AX08 D133 221 (0.18)*

Downdraft table D039 266 0.29

1/24/2008

Workstation near post 

AQ01

D039 467 0.11

Workstation near post 

BA01

D039 511 0.14

OSHA PEL 15

ACGIH TLV 10†

*Values in parentheses indicate a concentration between the MDC and the MQC. 

†Inhalable fraction

Table 3. PBZ air sample results for respirable dust (January 23–24, 2008)

Date Job Title Department 

Number

Sampling Time Air Concentration

(minutes) (mg/m3)

1/23/2008

SMA D133 200 (0.26)*

SMA D039 246 0.29

SMA D039 282 (0.078)*

1/24/2008

SMA D039 444 (0.10)*

SMA D039 508 (0.042)*

SMA D039 436 (0.075)*

 OSHA PEL 5

 ACGIH TLV 3

*Values in parentheses indicate a concentration between the MDC and the MQC.
Health Hazard Evaluation Report 2007-0344-3104 Page 5

Results (continued) CO concentrations on both days of monitoring were also well 

below the applicable OELs [NIOSH 2005]. Temperature and 

relative humidity measurements were within recommended 

ASHRAE guidelines [ASHRAE 2007].

Table 4. Environmental air sampling results in D133

Date Sampling Time

Air Concentration (ppm) 

Mean (Min–Max) 

CO

Mean 

Temperature 

( ̊F)

Mean RH 

(%)

01/23/2008 10:58 a.m.–02:11 p.m. 3 (0–13) 77.8 14.1

01/24/2008 08:16 a.m.–02:10 p.m. 0 (0–2) 71.9 10.5

Employee Interviews 

We privately interviewed 16 employees, including eight men and 

eight women. Five employees worked in D133, and 11 employees 

worked in D039. These employees represented almost all of the 

employees working in these two locations. Most of the interviewed 

employees worked as SMAs. Their average length of employment 

at Cessna was 5.3 years, and the average length of employment in 

their current department was 1.7 years. Job duties included drilling 

holes, grinding composites, and riveting. Employees reported 

exposures to methyl propyl ketone, sealants, alcohol, alodine, and 

glue.

Of the interviewed employees, 43% (7/16) reported that they 

had no health symptoms related to their work. While 12% (2/16) 

of interviewed employees reported headaches, none reported 

dizziness, fatigue, or abdominal pain. Twenty-five percent (4/16) 

reported that they had pre-existing asthma, and three of the four 

reported that their asthma was worse at work. All four employees 

with asthma worked as SMAs, but only one reported grinding 

composites. One employee reported a new diagnosis of asthma but 

declined our request for a personal medical record review. Eighteen 

percent (3/16) of interviewed employees reported skin symptoms 

including hives, itchiness, and other rash, and two of them 

reported grinding composites. 

Document Review 

We reviewed three reports of air sampling conducted by Cessna’s 

staff in D039 and/or D133. In September 2003, three full-shift 
Page 6 Health Hazard Evaluation Report 2007-0344-3104

Results (continued) PBZ air samples were collected with 3M organic vapor passive 

badges from D133 employees for total volatile organic compounds. 

The air samples were analyzed for methyl propyl ketone, n-hexane, 

toluene, and xylene. All the reported TWA air concentrations were 

below the applicable OELs. In September 2006, Cessna conducted 

air sampling in response to an employee complaint to OSHA about 

CO2 exposures in D133. Spot measurements were taken with a 

direct reading instrument at three different locations in D133; 

the CO2 concentrations ranged from 289–333 ppm. The outdoor 

CO2 air concentration was not reported. In September 2007, 

one PBZ air sample for respirable dust was collected on an SMA, 

and one GA air sample for total dust was collected in D039. CO 

concentrations were also monitored in D039 with a direct reading 

instrument. The PBZ respirable dust concentration was 0.16 

mg/m3, and the GA total dust concentration was 0.23 mg/m3. 

These results were similar to our air sampling results and were 

below the applicable OELs. The TWA CO concentration was 

0.86 ppm and was below applicable OELs.

Review of the D039 downdraft table maintenance chart showed 

that filters were changed when the pressure drop across the filters 

reached 3.5–4 inches of water on the magnahelic® gauge, which is 

in accordance with the manufacturer’s recommendation. During 

our site visit we were informed that the composite materials were 

made using isocyanates. However, our subsequent review of the 

MSDSs indicated that the composite materials used in these 

departments were made using epoxy novolac resin, BADGE (a 

building block for epoxy resin), and cyanoguanidine (an amine).

The Health Services manager provided us with a letter containing 

the details of incident reports from 2007, when four employees 

presented with work-related complaints. All four employees 

reported respiratory symptoms including chest pain, cough, and 

difficulty breathing; three also reported skin irritation, and two 

reported dizziness. The Health Services department concluded 

that the symptoms of two employees were not work related. One 

employee was thought to have symptoms consistent with personal 

tobacco use, and the other employee was found to have a preexisting medical condition. The other two employees reporting 

symptoms reported skin irritation and breathing difficulty but had 

no objective findings on clinical exam. These two employees had 

no further complaints after the original visit to Health Services 

[Gilbert 2007]. The work locations of these four individuals within 

the facility were not included in this letter.
Health Hazard Evaluation Report 2007-0344-3104 Page 7

Results (continued) Most cases recorded in the OSHA Logs were musculoskeletal. 

The 2005 OSHA Log contained an entry concerning a rash on 

the hands of an SMA and two entries concerning lung irritation 

in an administrator and in an assembler/sealer. The 2006 OSHA 

Log contained one entry concerning a rash in a paint preparation 

worker, and the 2007 OSHA Log contained an entry concerning 

a rash in an SMA. No entries concerning lung irritation were 

recorded in 2006 and 2007. It is not known in which departments 

the OSHA-recordable injured or ill employees were working.

Other Observations 

In D039 and D133, Cessna employees use very small quantities of 

paint and sealants for touching up parts. We observed that paint 

was mostly stored in small cans, which had lids, and employees 

used a brush to touch up metal parts. Review of the MSDSs 

for paints and sealants used in these departments indicated 

the presence of solvents such as methyl propyl ketone, toluene, 

and xylene. The inhalation exposure potential to employees 

during the touch-up task is limited as the task duration is short, 

and employees close the cans after use. Also, excess paint and 

other sealants are stored separately, and some are stored in a 

locked refrigerator. Review of Cessna’s air sampling report also 

indicated that employee exposures to these solvents were below the 

applicable OELs. Based on this information, we did not evaluate 

these potential exposures further.

Historically, dust generated from grinding cured composite 

materials has been considered to be inert [Boatman et al. 1987; 

Hathaway and Proctor 2004]. However, studies have shown that 

employees working with epoxy-containing composite materials 

are at risk of developing asthma. Case studies have shown that 

employees working with composite material ingredients such 

as bisphenol-A and BADGE can develop occupational asthma 

[Kanerva et al. 2000; Hannu et al. 2008]. Employees can also 

develop asthma when inhaling vapors generated during curing or 

when grinding cured epoxy resins [Asthma induced by epoxy resin 

systems 1977; Ward and Davies 1982; Hathaway and Proctor 2004]. 

Epoxies are sensitizing agents and can cause health effects at very 

low levels, far below the applicable OELs.

Discussion
Page 8 Health Hazard Evaluation Report 2007-0344-3104

Three employees with pre-existing asthma reported worsening 

of their asthma at work. Only one of these employees worked 

grinding composite materials, but the other two worked in the 

vicinity of other employees grinding composites. Another reported 

new onset asthma since working at Cessna. While 9 (56%) out of 

16 employees interviewed during our site visit reported various 

work-related health symptoms, these symptoms did not appear to 

be reported in the Health Services incident reports or the OSHA 

Logs. 

Our air sampling results indicated that employees’ exposures to 

total and respirable dust are below the OSHA PELs and ACGIH 

TLVs. It is possible, however, that the reported respiratory 

symptoms are work related. NIOSH does not have an REL for total 

and respirable dust but concluded in 1988 that the documentation 

cited by OSHA for a reduced PEL (8-hour TWA) of 10 mg/m3

for total dust was inadequate and may not protect employee 

health [NIOSH 2005]. Similarly, ACGIH TLVs for inhalable and 

respirable dust are applicable only when dust particles are insoluble 

or poorly soluble in water and have low toxicity [ACGIH 2009]. 

Dust generated from grinding of composite materials can contain 

reactive components; therefore, caution must be exercised when 

interpreting air sampling concentrations for total and respirable 

dust samples in this setting.

Current sampling methods for dusts containing composite material 

require sampling for total dust. Although NIOSH has a draft air 

sampling method for BADGE, one possible component in the 

dust, no OELs for specific components of composite dust have 

been established. In addition, there are no OELs for composite 

dust as a whole, unlike welding or metalworking fluids [NIOSH 

2005]. Composite materials manufactured with different chemicals 

and additives can have other reactive components that can 

exacerbate respiratory symptoms in predisposed employees. In 

addition, dust generated during grinding of composites is mostly in 

the respirable size range, which allows these particles to deposit in 

the bronchial and alveolar regions of the lung. 

Our air sampling results for CO indicated that the air 

concentrations were below all the applicable OELs. Cessna’s 

air sampling reports showed that CO, total dust, and respirable 

dust concentrations were similar to our air sampling results. 

Temperature and relative humidity measurements collected during 

our visit were within the recommended ASHRAE guidelines 

[ASHRAE 2007]. 
Health Hazard Evaluation Report 2007-0344-3104 Page 9

Discussion (continued) The capture efficiency of the D039 downdraft table can be affected 

by even moderate room air currents. Use of baffles on three sides 

of the table (i.e., back and side shields) will help increase the 

capture efficiency of the downdraft table by reducing interfering 

room air currents [ACGIH 2007]. If employees continue to grind at 

their work stations, use of local exhaust ventilated (shrouded) tools 

can help reduce employee exposure to composite dust [ACGIH 

2007; 29 CFR 1910.94 (b)]. 

We observed that some employees wearing elastomeric respirators 

had facial hair in the sealing area. This prevents the respirator from 

creating a good seal around the face and substantially reduces the 

protection afforded by respirators. 

Employee exposures to total and respirable dust in D039 and D133 

were below the applicable OELs. However, dust generated from 

grinding of composite materials can contain reactive components 

that can cause health effects at levels far below the applicable 

OELs. Three employees reported worsening of their asthma at 

work, and one reported new onset asthma since working at Cessna. 

Despite low levels of total and respirable dust and metals, it is 

possible that these reported respiratory symptoms are work related. 

CO levels in both departments were below the applicable OELs 

and did not present a health hazard. 

Based on our findings, we recommend the actions listed below 

to create a more healthful workplace. These recommendations 

apply not only to D039 and D133 but also to similar operations 

throughout the facility. We encourage Cessna to use its labormanagement health and safety committee or working group to 

discuss the recommendations in this report and develop an action 

plan. Those involved in the work can best set priorities and assess 

the feasibility of our recommendations for the specific situation 

at Cessna. Our recommendations are based on the hierarchy of 

controls approach (Appendix B: Occupational Exposure Limits 

and Health Effects). 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 

Conclusions

Recommendations
Page 10 Health Hazard Evaluation Report 2007-0344-3104

Recommendations

(continued) not effective or feasible, administrative measures and/or personal 

protective equipment may be needed. 

Engineering Controls

Engineering controls reduce exposures to employees by removing 

the hazard from the process or placing a barrier between the 

hazard and the employee. Engineering controls are very effective 

at protecting employees without placing primary responsibility of 

implementation on the employee. 

1. Use downdraft tables when grinding on composite 

materials. Downdraft tables should have baffles on three 

sides to reduce interference from room air currents and 

increase the capture efficiency of the table. ACGIH 

recommends that a downdraft table or a hand grinding 

bench have a flow rate range of 150–250 cubic feet per 

minute per square foot of bench area and a minimum duct 

velocity of 3500 feet per minute. Please refer to the ACGIH 

publication Industrial Ventilation: A Manual of Recommended 

Practice for Design for further guidance on selecting local 

exhaust hoods appropriate to your processes [ACGIH 2007]. 

2. Provide shrouded grinding and buffing tools to employees 

when the task prevents the use of the downdraft tables. 

Please refer to the above mentioned ACGIH publication 

and OSHA ventilation standard (29 CFR 1910.94) for 

guidance on minimum exhaust flow rates required for 

shrouded tools [http://www.osha.gov/pls/oshaweb/

owadisp.show_document?p_table=STANDARDS&p_

id=9734].

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 are necessary to ensure that control policies and 

procedures are not circumvented in the name of convenience or 

production.
Health Hazard Evaluation Report 2007-0344-3104 Page 11

Recommendations

(continued) 1. Encourage employees to report all work-related health 

concerns to Cessna’s onsite medical clinic. These problems 

should be investigated on an individual basis by the 

company and contracted healthcare providers. 

2. Reassign employees determined to have health effects 

resulting from work related exposures to areas with 

minimum or nonexistent exposures. Employees reassigned 

for work-related medical reasons should not lose seniority, 

wages, or other benefits to which they would be entitled had 

they not been reassigned. 

PPE is the least effective means for controlling employee exposures. 

Proper use of PPE requires a comprehensive program, and calls 

for a high level of employee involvement and commitment to be 

effective. The use of PPE requires the choice of the appropriate 

equipment to reduce the hazard and the development of 

supporting programs such as training, change-out schedules, and 

medical assessment if needed. PPE should not be relied upon as 

the sole method for limiting employee exposures. Rather, PPE 

should be used until engineering and administrative controls can 

be demonstrated to be effective in limiting exposures to acceptable 

levels. 

1. Provide a copy of Appendix D of 29 CFR 1910.134 to 

employees who continue to wear respirators voluntarily.

2. Encourage employees who voluntarily wear respirators to 

follow all aspects of proper respirator use including being 

clean shaven when using the respirator to ensure a good 

seal. 

ACGIH [2007]. Specific operations. In: Industrial ventilation: A 

manual of recommended practice for design. 26th ed. Cincinnati, 

OH: American Conference of Governmental Industrial Hygienists, 

pp.13-1–13-192.

ACGIH [2009]. 2009 TLVs® and BEIs®: threshold limit values for 

chemical substances and physical agents and biological exposure 

indices. Cincinnati, OH: American Conference of Governmental 

Industrial Hygienists.

References
Page 12 Health Hazard Evaluation Report 2007-0344-3104

References (continued) ASHRAE [2007]. Industrial air conditioning. In: 2007 ASHRAE 

Handbook–HVAC Applications. I-P Edition. Atlanta, GA: 

American Society of Heating, Refrigerating and Air-Conditioning 

Engineers, Inc., p. 12.4.

Asthma induced by epoxy resin systems [1977]. Brit Med J 

2(6088):655.

Boatman ES, Covert D, Kalman D, Luchtel D, and Osmenn 

GS [1988]. Physical, morphological, and chemical studies of 

dust derived from machining of composite-epoxy materials. Env 

Research 45(2):242–255.

CFR. Code of Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the Federal Register.

Gilbert PM [2007]. Letter of October 10, 2007, from P.M. Gilbert, 

Manager, Health Services, Cessna, to Srinivas Durgam, Division 

of Surveillance, Hazard Evaluations, and Field Studies, National 

Institute for Occupational Safety and Health, Centers for Disease 

Control, U.S. Department of Health and Human Services.

Hannu T, Frilander H, Kauppi P, Kuuilala O, Alanko K [2008]. 

IgE-mediated occupational asthma from epoxy resin. Int Arch 

Allerg Immunol 148(1):41–44.

Hathaway GJ, Proctor NH, eds. [2004]. Chemical hazards of the 

workplace, 5th ed. New Jersey: John Wiley and Sons, Incorporated, 

pp. 298–301.

Kanerva L, Estlander T, Keskien H, Jolank R [2000]. Occupational 

allergic airbone contact dermatitis and delayed bronchial asthma 

from epoxy resin revealed by bronchial provocation test. Eur J 

Dermatol 10(6):475–477.

NIOSH [2005]. NIOSH pocket guide to chemical hazards. 

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

Centers for Disease Control and Prevention, National Institute 

for Occupational Safety and Health, DHHS (NIOSH) Publication 

No. 2005-149. [http://www.cdc.gov/niosh/npg/]. Date accessed: 

February 2010.

Ward MJ, Davies D [1982]. Asthma due to grinding epoxy resin 

cured with pthallic anhydride. Clin Allerg 13(2):165–168.
Health Hazard Evaluation Report 2007-0344-3104 Page 13

Total Dust and Metals

Air samples were collected on tared 37-mm diameter, 5-μm pore size polyvinyl chloride filters using SKC 

Air Check® 2000 air sampling pumps calibrated at a flow rate of 2 liters per minute. The inlet port of 

the sampling pump was connected to the sampling media with Tygon® tubing. All air sampling pumps 

were calibrated before and after use. For PBZ samples, the sampling media was attached to the employee’s 

lapel within the breathing zone, roughly defined as an area in front of the shoulders with a radius of 6 to 9 

inches. All samples were first analyzed gravimetrically according to NIOSH Method 0500 [NIOSH 2009]. 

These air samples were subsequently analyzed for metals by inductively coupled argon plasma-atomic 

emission spectroscopy according to NIOSH Method 7303 [NIOSH 2009].

For total dust samples, the limit of detection was 0.030 mg/sample, and the limit of quantitation was 

0.093 mg/sample. The MDC and MQC were obtained by dividing the analytical limit of detection and 

the limit of quantitation, respectively, by the sample volume. Therefore, for a sample volume of 0.96 m3, 

the MDC was 0.031 mg/m3, and the MQC was 0.097 mg/m3.

Respirable Dust 

Air samples were collected on tared 37-mm diameter, 5-μm pore size polyvinyl chloride filters with SKC 

Air Check® 2000 air sampling pumps calibrated at a flow rate of 1.7 liters per minute. Nylon cyclones 

were used as preselectors for the respirable dust samples because they match the 4-μm, 50% cut, respirable 

curve. All samples were analyzed gravimetrically according to NIOSH Method 0600 [NIOSH 2009]. 

For respirable dust samples the limit of detection was 0.030 mg/sample, and the limit of quantitation 

was 0.093 mg/sample. Therefore, for a sampling volume of 0.96 m3, the MDC was 0.031 mg/m3, and the 

MQC was 0.097 mg/m3.

Reference 

NIOSH [2009]. NIOSH manual of analytical methods (NMAM®), 4th ed. Schlecht PC, O’Connor PF, 

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

and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 

94–113 (August, 1994); 1st Supplement Publication 96–135, 2nd Supplement Publication 98–119; 3rd 

Supplement 2003–154. [http://www.cdc.gov/niosh/docs/2003-154/].

Appendix A: Methods
Page 14 Health Hazard Evaluation Report 2007-0344-3104

In evaluating the hazards posed by workplace exposures, NIOSH investigators use both mandatory (legally 

enforceable) and recommended OELs for chemical, physical, and biological agents as a guide for making 

recommendations. OELs have been developed by Federal agencies and safety and health organizations to 

prevent the occurrence of adverse health effects from workplace exposures. Generally, OELs suggest levels 

of exposure that most employees may be exposed 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 from 

adverse health effects even if their exposures are maintained below these levels. A small percentage may 

experience adverse health effects because of individual susceptibility, a preexisting medical condition, and/

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

workplace exposures, the general environment, or with medications or personal habits of the employee 

to produce health effects even if the occupational exposures are controlled at the level set by the exposure 

limit. Also, some substances can be absorbed by direct contact with the skin and mucous membranes in 

addition to being inhaled, which contributes to the individual’s overall exposure. 

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 STEL or ceiling 

values where health effects are caused by exposures over a short period. Unless otherwise noted, the STEL 

is a 15-minute TWA exposure that should not be exceeded at any time during a workday, and the ceiling 

limit is an exposure that 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, while others are 

recommendations. The U.S. Department of Labor OSHA PELs (29 CFR 1910 [general industry]; 29 

CFR 1926 [construction industry]; and 29 CFR 1917 [maritime industry]) are legal limits enforceable in 

workplaces covered under the Occupational Safety and Health Act. NIOSH RELs are recommendations 

based on a critical review of the scientific and technical information available on a given hazard and the 

adequacy of methods to identify and control the hazard. NIOSH RELs can be found in the NIOSH Pocket 

Guide to Chemical Hazards [NIOSH 2005]. NIOSH also recommends different types of 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 from these hazards. Other OELs that are commonly used and cited in the United States include 

the TLVs recommended by ACGIH, a professional organization, and the WEELs recommended by the 

American Industrial Hygiene Association, another professional organization. The TLVs and WEELs are 

developed by committee members of these associations from a review of the published, peer-reviewed 

literature. They are not consensus standards. ACGIH TLVs are considered voluntary exposure guidelines 

for use by industrial hygienists and others trained in this discipline “to assist in the control of health 

hazards” [ACGIH 2009]. WEELs have been established for some chemicals “when no other legal or 

authoritative limits exist” [AIHA 2009].

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

both legal and recommended limits. Since 2006, the Berufsgenossenschaftliches Institut für Arbeitsschutz 

(German Institute for Occupational Safety and Health) has maintained a database of international 

Appendix B: Occupational Exposure Limits & Health Effects
Health Hazard Evaluation Report 2007-0344-3104 Page 15

Appendix B: Occupational Exposure Limits & Health Effects (continued)

OELs from European Union member states, Canada (Québec), Japan, Switzerland, and the United 

States available at http://www.dguv.de/bgia/en/gestis/limit_values /index.jsp. The database contains 

international limits for over 1250 hazardous substances and is updated annually. 

Employers should understand that not all hazardous chemicals have specific OSHA PELs, and for some 

agents the legally enforceable and recommended limits may not reflect current health-based information. 

However, an employer is still required by OSHA to protect its employees from hazards even in the absence 

of a specific OSHA PEL. 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))]. Thus, NIOSH investigators encourage 

employers to make use of other OELs when making risk assessment and risk management decisions to 

best protect the health of their employees. NIOSH investigators also encourage the use of the traditional 

hierarchy of controls approach to eliminate or minimize identified 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 that focuses resources on exposure controls by describing how a risk 

needs to 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 the OELs, when available.

Total and Respirable Dust 

Respirable particulates are those particles that when inhaled can be deposited in the gas exchange region 

[ACGIH 2009]. Total dust refers to particulates that may be deposited anywhere in the respiratory 

tract. Total dust includes respirable particulates. OSHA has 8-hour PEL-TWAs for respirable and total 

particulates (particulates not otherwise regulated) of 5 and 15 mg/m3 respectively. The ACGIH position 

is that all particles, even if they are biologically inert or not soluble, may have adverse health effects. 

Therefore, ACGIH therefore recommends that exposure to respirable particles not exceed 3 mg/m3 and 

exposure to inhalable particles not exceed 10 mg/m3. These recommendations are for particles that do 

not have a specific TLV, are of low toxicity, and are referred to by ACGIH as particles (insoluble or poorly 

soluble) not otherwise specified [ACGIH 2009]. 

Carbon Monoxide 

Carbon monoxide is a colorless, odorless, tasteless gas that can be a product of the incomplete combustion 

of organic compounds. It is classified as a chemical asphyxiant because it combines with hemoglobin 

and interferes with the oxygen carrying capacity of blood. Symptoms of overexposure include headache, 
Page 16 Health Hazard Evaluation Report 2007-0344-3104

Appendix B: Occupational Exposure Limits & Health Effects (continued)

drowsiness, dizziness, nausea, and vomiting. Collapse, myocardial ischemia, and death can also result 

[LaDou 2004]. The NIOSH REL for CO is 35 ppm for an 8-hour TWA. NIOSH also recommends a 

ceiling limit of 200 ppm, which should not be exceeded at any time during the workday [NIOSH 2005]. 

The OSHA PEL for CO is 50 ppm for an 8-hour TWA. The ACGIH TLV for CO is 25 ppm as an 8-hour 

TWA. This value is intended to maintain blood carboxyhemoglobin levels below 3.5%, to minimize the 

potential for adverse neurological behavioral changes, and to maintain cardiovascular work and exercise 

capacities. The time to reach a carboxyhemoglobin level of 3.5% at a given CO concentration decreases 

as the workload increases [ACGIH 2001]. Carboxyhemoglobin levels are elevated in active smokers 

but usually do not exceed 10% (values range between 4%–7% for a two-pack-per-day cigarette smoker). 

Carboxyhemoglobin levels above 50% can be lethal [LaDou 2004].

References 

ACGIH [2001]. Documentation of the threshold limit values and biological exposure indices. 7th ed. 

Cincinnati, OH: American Conference of Governmental Industrial Hygienists; 2002–2008 Suppl.

ACGIH [2009]. 2009 TLVs® and BEIs®: threshold limit values for chemical substances and physical 

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

Industrial Hygienists.

AIHA [2009]. AIHA 2009 Emergency response planning guidelines (ERPG) & workplace environmental 

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

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

Federal Register.

LaDou J, ed. [2004]. Current occupational and environmental medicine. 3rd ed. USA: McGraw-Hill 

Companies, Inc., pp. 541–543.

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

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

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

accessed: February 2010.
Health Hazard Evaluation Report 2007-0344-3104 Page 17

Acknowledgments and

Availability of Report

The Hazard Evaluations and Technical Assistance Branch 

(HETAB) of the National Institute for Occupational Safety and 

Health (NIOSH) conducts field investigations of possible health 

hazards in the workplace. These investigations are conducted 

under the authority of Section 20(a)(6) of the Occupational Safety 

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

the Secretary of Health and Human Services, following a written 

request from any employer or authorized representative of 

employees, to determine whether any substance normally found 

in the place of employment has potentially toxic effects in such 

concentrations as used or found. HETAB also provides, upon 

request, technical and consultative assistance to federal, state, and 

local agencies; labor; industry; and other groups or individuals to 

control occupational health hazards and to prevent related trauma 

and disease.

The findings and conclusions in this report are those of the 

authors and do not necessarily represent the views of NIOSH. 

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do 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.

This report was prepared by Srinivas Durgam and Marie A. de 

Perio of HETAB, Division of Surveillance, Hazard Evaluations and 

Field Studies. Medical field assistance was provided by Ayodele 

Adebayo. Analytical support was provided by Bureau Veritas 

North America. Health communication assistance was provided 

by Stefanie Evans. Editorial assistance was provided by Ellen 

Galloway. Desktop publishing was performed by Robin Smith.

Copies of this report have been sent to employee and 

management representatives at Cessna Aircraft Company, the 

state health department, and the Occupational Safety and Health 

Administration Regional Office. This report is not copyrighted and 

may be freely reproduced. The report may be viewed and printed at 

http://www.cdc.gov/niosh/hhe/. Copies may be purchased from the 

National Technical Information Service at 5825 Port Royal Road, 

Springfield, Virginia 22161.
Below is a recommended citation for this report:

NIOSH [2009]. Health hazard evaluation report: evaluation of potential exposures 

during composite grinding at an aircraft manufacturing plant, Wichita, KS. By 

Durgam S, de Perio MA. Cincinnati, OH: U.S. Department of Health and Human 

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

Occupational Safety and Health, NIOSH HETA No. 2007-0344-3104.

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