Evaluation of Exposure 

to Toluene, Ethanol, 

and Isopropanol 

at an Electronics 

Manufacturer – Ohio 

R. Todd Niemeier, MS, CIH 

Health Hazard Evaluation Report

HETA 2009-0070-3137

August 2011

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health

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

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

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

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

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

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

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2009-0070-3137 Page i

Appendix A

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

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

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

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

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

Results and Discussion .......................................................3

Conclusions.........................................................................7

Recommendations...............................................................7

References ..........................................................................9

Contents

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

Methods.............................................................................11

Occupational Exposure Limits and Health Effects.............13

Acknowledgments

Appendix B
Page ii Health Hazard Evaluation Report 2009-0070-3137

°F Fahrenheit

ACGIH® American Conference of Governmental Industrial Hygienists

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

CFR Code of Federal Regulations

fpm Feet per minute

ft2 Square feet

GA General area

HHE Health hazard evaluation

LEV Local exhaust ventilation

mg Milligram

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

STEL Short-term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

WEELTM Workplace environmental exposure level

Abbreviations
Health Hazard Evaluation Report 2009-0070-3137 Page iii

What NIOSH Did

● We evaluated the facility on February 23, 2009, and again on 

June 18, 2009.

● We looked at work processes, practices, and conditions at 

the facility. We also talked with employees about their work 

practices and processes.

● We took air samples for toluene and ethanol during gluing 

and oven curing operations.

● We took air samples for isopropanol during shell dipping 

operations.

● We evaluated the local exhaust ventilation in the gluing and 

oven curing area.

● We tested for lead on the surface of electrical shells.

What NIOSH Found

● Exposures to toluene, ethanol, and isopropanol were low. 

The levels we found were well below occupational exposure 

limits.

● Local exhaust ventilation was not always effective in 

controlling nuisance odors in the gluing and oven curing 

area.

● Lead was not detected on the electrical shells.

What Managers Can Do

● Improve the local exhaust ventilation in the gluing and oven 

curing area.

● Consider adding local exhaust ventilation in the shell 

dipping area if isopropanol nuisance odors continue to be a 

problem.

● Give employees who voluntarily wear respiratory protection 

a copy of the OSHA Respiratory Protection Standard. This 

document can be found in Appendix D of the standard.

What Employees Can Do

● Keep glue and isopropanol lubricant off of your skin. If you 

can’t do this through careful handling of parts, you should 

wear gloves.

The National Institute for 

Occupational Safety and 

Health (NIOSH) received a 

management request for 

a health hazard evaluation 

(HHE) at an electronics 

manufacturer in Ohio. 

Managers were concerned 

about the potential 

hazards from chemical 

odors in the electrical 

connecter assembly 

operations.

Highlights of the

NIOSH Health

Hazard Evaluation
Page iv Health Hazard Evaluation Report 2009-0070-3137

In January 2009, NIOSH received an HHE request from an 

electronics manufacturer in Ohio. The request concerned the 

potential for exposure to toluene and ethanol when gluing and 

oven curing electrical contacts to electrical shells and exposure to 

isopropanol when placing rubber inserts and electrical contacts 

into electrical shells.

NIOSH investigators made site visits to the electronics 

manufacturer facility on February 23, 2009, and June 18, 2009. 

We walked through the facility and observed work processes, 

practices, and conditions. We spoke with employees about health 

and workplace concerns and collected air samples. We used 

colorimetric detection tubes on February 23, 2009, to estimate 

air concentrations of toluene and ethanol in the gluing and oven 

curing area. On a return site visit on June 18, 2009, we collected 

full-shift and short-term air samples for toluene and ethanol in 

the gluing and oven curing area. We also collected task-based and 

short-term air samples for isopropanol in the shell dipping area. 

We evaluated the LEV in the gluing and oven curing area using a 

thermoanemometer and smoke tubes. Finally, we used colorimetric 

lead swabs to determine if lead was present on the electrical shells.

We detected measurable levels of toluene, ethanol, and 

isopropanol; however, all samples were less than 6% of applicable 

OELs. Some skin contact to isopropanol was observed during the 

shell dipping process. Employees did not wear gloves to protect 

against skin exposure to these chemicals. LEV systems in the gluing 

and oven curing area were present but were not working optimally. 

Lead was not detected on the surface of the electrical shells.

Several strategies could be used to minimize exposures and improve 

effectiveness of the LEV systems in the gluing and oven curing 

area. When the LEV on either the gluing station or oven is not in 

use, close the damper to increase the capture efficiency. Redesign 

the hood types and/or place the hoods closer to contaminants 

for better capture efficiency. Similarly, for the shell dipping area, 

an LEV unit could be added to reduce nuisance odors. Gloves 

should be used if dermal exposure to the glue or shell dipping 

solution is anticipated. Employees who choose to wear respiratory 

protection voluntarily during work activities should be provided 

with Appendix D of the OSHA Respiratory Protection Standard 

(29 CFR 1910.134).

NIOSH investigators 

evaluated the potential for 

exposure to chemicals at 

an electrical connector 

manufacturer. We found 

that the air concentrations 

of toluene, ethanol, and 

isopropanol were very 

low, less than 6% of 

OELs. To reduce toluene 

and ethanol nuisance 

odors, we recommend 

changes to the LEV in 

the gluing and oven 

curing area. Additionally, 

installing LEV in the shell 

dipping area may reduce 

isopropanol nuisance 

odors.

Summary

Keywords: NAICS 423690 (Other electronic parts and equipment 

merchant wholesalers), toluene, ethanol, isopropanol, lead, CAS 

64-17-5, CAS 67-63-0, CAS 108-88-3, CAS 7439-92-1, local exhaust 

ventilation, LEV, nuisance odors, skin contact
Health Hazard Evaluation Report 2009-0070-3137 Page 1

Introduction

NIOSH received a management request for an HHE at an Ohio 

electronics manufacturer on January 16, 2009. The request 

concerned the potential for exposure to chemicals during assembly, 

gluing, and oven curing of electrical connectors. In response to the 

HHE request, NIOSH investigators visited the facility on February 

23, 2009, and June 18, 2009, to evaluate employee exposures to 

toluene, ethanol, and isopropanol. We also evaluated engineering 

controls in the gluing and oven curing area.

Process Description 

The electronics manufacturer built electrical connectors for the 

electronics and automobile industries. The facility consisted of two 

buildings. One building served as a warehouse and an office. The 

other building was used for manufacturing operations including 

shell dipping, assembly, gluing, and oven curing of electrical 

connectors. At the time of the evaluation 16 employees were at the 

facility, two of whom worked in the manufacturing building.

In the assembly area, one employee dipped metal electrical shells 

containing rubber inserts into a 50:50 ratio of isopropanol in 

water. This mixture acted as a lubricant so that electrical contacts 

could be placed into these rubber inserts. The employee was not 

wearing gloves, and no ventilation controls were present in this 

area.

In the gluing area, one employee glued electrical contacts onto 

the rubber inserts using a small amount (approximately 1–5 

milliliters) of glue fed through a foot-controlled syringe that was 

mounted to the workstation. Approximately 500–800 contacts 

were glued per hour. After the contacts were glued in place, the 

electrical connectors were placed in a small oven and cured for 

approximately 20 minutes at 320°F. LEV systems were used in this 

area, which included a dampered flex-tube exhaust vent with a 

round inlet approximately 9 inches above the gluing station and a 

dampered canopy exhaust hood over the oven to capture heat and 

chemical vapors from the curing process. After air was collected 

by the LEV systems, it passed through an energy recovery unit and 

was exhausted to the outside on the rooftop of the building. The 

gluing and oven curing processes were performed intermittently; 

approximately 1 gallon of glue was used every 3–4 months. The 

gluing and oven curing employee wore an N95 filtering facepiece 

respirator with a carbon filter to reduce nuisance odors (Moldex® 

2801N95, Culver City, California) during gluing activities.
Page 2 Health Hazard Evaluation Report 2009-0070-3137

Introduction 

(continued)

Assessment

Manufacturer information on hazardous metal content in the 

electrical shells was provided by the electronics manufacturer. 

This information indicated that the electrical shells had low 

concentrations of lead and cadmium.

Initial Evaluation 

On February 23, 2009, we held an opening meeting with 

management and employee representatives followed by a 

tour of the facility. We talked with employees, observed work 

procedures, and used colorimetric detection tubes to evaluate air 

concentrations of toluene and ethanol during gluing and oven 

curing processes. We also evaluated the LEV in the gluing and oven 

curing area. This included measuring the rate of air flow across 

the face of the oven canopy exhaust hood and gluing station flextube exhaust vent. We used smoke to visualize how well the LEV 

captured air near the gluing and oven stations. Specifically, smoke 

was generated at the gluing station and oven door to determine if 

the LEV for each of these processes could effectively capture the 

smoke. Air flow measurements were made, and smoke capture was 

observed when the dampers were open on both LEV systems. We 

repeated these measurements at the oven canopy exhaust hood 

after closing the damper on the gluing station flex-tube exhaust 

vent. Similarly, measurements were repeated at the gluing station 

flex-tube exhaust vent after closing the damper on the oven canopy 

exhaust hood.

Return Evaluation 

We made a return visit on June 18, 2009, to collect full-shift and 

short-term PBZ and GA air samples for toluene and ethanol during 

gluing and oven curing processes. PBZ air samples were collected 

on the gluing and oven curing operator over the entire work shift. 

Additional short-term PBZ air samples were collected for toluene 

and ethanol on this same employee during gluing and when 

loading and unloading the oven with electrical connectors. Fullshift GA air samples for toluene and ethanol were also collected 

near the oven.

One task-based (164 minutes) and two short-term PBZ samples 

(15 to 16 minutes each) were collected on another employee 
Health Hazard Evaluation Report 2009-0070-3137 Page 3

Assessment (continued) for isopropanol during the shell dipping operation. After the 

shell dipping process was completed, the operator removed the 

isopropanol from the work area and worked on other job tasks 

(without isopropanol exposure) for the remainder of the work 

shift. A full-shift sample was not collected because no exposure to 

isopropanol was anticipated after the operator finished the shell 

dipping process. The time that it takes to complete this process is 

highly variable and is dependent on work load.

We also tested the surface of the electrical shells for lead using 

colorimetric swabs. Details on the methods for air and surface 

sampling, environmental measurements, and the LEV system 

evaluation are presented in Appendix A. A discussion on OELs 

and potential health effects is presented in Appendix B.

Air Sampling 

Colorimetric detection tube samples were used as a screening 

tool to help determine the sampling strategy used during the site 

visit on June 18, 2009. Our colorimetric detection tube results 

from February 23, 2009, indicated that toluene and ethanol were 

present in the air near the gluing and oven curing operator during 

the gluing process. Instantaneous concentrations ranged from 

5–10 ppm for toluene and 500–1000 ppm for ethanol. Toluene 

and ethanol concentrations were below the limit of detection 

for samples collected near the oven door when it was opened to 

unload cured connectors. The colorimetric tubes have a detection 

limit of 5 ppm for toluene and 25 ppm for ethanol. The toluene 

concentrations that were measured were well below the NIOSH 

STEL and OSHA ceiling and peak limits (Table 1). Ethanol has 

no STELs; however, these results revealed that ethanol was present 

in the gluing process, which confirmed our decision to conduct 

follow-up sampling for ethanol on the second site visit.

Tables 1–3 provide the results for the PBZ and GA integrated air 

sampling for toluene, ethanol, and isopropanol conducted on 

June 18, 2009. Full-shift PBZ and GA samples for toluene and 

ethanol collected during gluing and oven curing operations showed 

detectable levels of these compounds; however, the exposures 

were <1% of applicable OELs (Tables 1 and 2). Similarly, shortterm PBZ samples for toluene and ethanol collected on the gluing 

Results and Discussion
Page 4 Health Hazard Evaluation Report 2009-0070-3137

Results and Discussion (continued) and oven curing operator when gluing were <1% of applicable 

OELs for these chemicals (Tables 1 and 2). The task-based 

isopropanol sample TWA was 9.5 ppm, which is less than 2% of 

existing OELs assuming no exposure for the employee during the 

unsampled time (Table 3). The short-term samples for isopropanol 

had concentrations less than 6% of existing STELs. All of the 

measured exposures for toluene, ethanol, and isopropanol were low 

compared to the most conservative OELs for these chemicals.

Table 1. PBZ and GA air sampling results for toluene during gluing and curing operations

Activity Sample 

Type

Total Time 

(minutes)

Volume 

(liters)

Sample 

Concentration 

(ppm)*

TWA 

Concentration 

(ppm)*

Gluing and Oven Curing 

PBZ

216

180

4.49

3.74

0.21

0.09

0.13

15 2.99 0.98 —

16 3.19 [0.06] —

GA

240

209

4.68

4.11

[0.04]

[0.04] [0.04]

OELs (ppm)

NIOSH REL† OSHA PEL† ACGIH TLV‡

100 TWA; 150 STEL 200 TWA; 300 ceiling; 500 peak 20 TWA

* Concentrations in brackets were between the minimum detectable concentration and the minimum 

quantifiable concentration (brackets are used to point out that there is more uncertainty associated with these 

values than with values above the minimum quantifiable concentration).

† [NIOSH 2005]

‡ [ACGIH 2010a]

Table 2. PBZ and GA air sampling results for ethanol during gluing and curing operations 

Activity Sample 

Type

Total Time 

(minutes)

Volume 

(liters)

Sample 

Concentration 

(ppm)

TWA 

Concentration 

(ppm)

Gluing and Oven Curing 

PBZ

218

180

10.79

8.91

4.0

0.8

2.6

16 0.795 ND* —

GA

245

214

12.59

10.99

0.5

0.6

0.5

OELs (ppm)

NIOSH REL† OSHA PEL† ACGIH TLV‡

1000 TWA 1000 TWA 1000 TWA

* Ethanol was not detected above the minimum detectable concentration of 2.5 ppm.

† [NIOSH 2005]

‡ [ACGIH 2010a]
Health Hazard Evaluation Report 2009-0070-3137 Page 5

Results and Discussion (continued)

The air concentrations measured for toluene and isopropanol on 

June 18, 2009, were above established odor thresholds for these 

chemicals [AIHA 1989], so it is not unexpected that nuisance odors 

were reported by employees in the areas where these chemicals were 

used.

Currently, employees do not wear gloves to protect against dermal 

exposure to the substances noted above. Although skin contact 

with the glue was not observed, some skin contact with the 

isopropanol-containing lubricant was noted. Employees rely on 

careful handling of parts while applying glue and lubricant. This 

practice has resulted in no dermal-related health concerns to date, 

but there is potential for dermal exposure. Even though employees 

work with small parts, commercially available high dexterity 

chemical protective gloves would help protect the employees’ skin 

while performing these tasks.

Wipe Sampling 

We did not detect lead on the surface of the electrical shells using 

colorimetric swab sampling. The colorimetric swabs are sensitive to 

a concentration of 1 microgram on solid surfaces.

Local Exhaust Ventilation 

Table 4 summarizes the smoke tube testing and air velocity 

measurements on the LEV used in the gluing and oven curing 

Table 3. PBZ sampling results for isopropanol during shell dipping operations 

Activity Sample 

Type

Total Time 

(minutes)

Volume 

(liters)

Sample 

Concentration 

(ppm)

TWA 

Concentration 

(ppm)

Shell dipping PBZ

114

50

2.25

0.99

9.4

9.9

9.5 

15 2.99 22 —

16 3.19 7.7 —

OELs (ppm)

NIOSH REL* OSHA PEL* ACGIH TLV†

400 TWA; 500 STEL 400 TWA 200 TWA; 400 STEL

* [NIOSH 2005]

† [ACGIH 2010a]
Page 6 Health Hazard Evaluation Report 2009-0070-3137

Results and Discussion (continued) area. Smoke tube testing demonstrated effective capture of 

smoke at the gluing station by the flex-tube exhaust vent when 

the damper on the canopy exhaust hood above the oven was 

closed. Similarly, effective capture of smoke at the oven door, by 

the canopy exhaust hood above the oven, was noted when the 

damper on the gluing station LEV was closed. When both dampers 

were open, both LEV systems showed some air turbulence and 

ineffective capture of smoke. The mean air velocities were higher 

for both LEV systems when the damper on the opposite LEV 

was closed. ASHRAE recommends that capture velocity, which is 

the air velocity at the point of contamination, should be 50–100 

fpm when contaminants are “released with essentially no velocity 

into still air” [ASHRAE 2007]. The capture velocity was 26 fpm 

at the gluing station with both dampers open, which is less than 

is recommended by the ASHRAE guidelines [ASHRAE 2007]. 

However, meeting this ASHRAE guideline may not necessarily 

reduce nuisance odors from the gluing process. Capture velocities 

were not collected at the oven, so a comparison to the ASHRAE 

guidelines cannot be made using our data.

Table 4. Evaluation of the LEV used in the gluing and oven curing area

Face velocity (fpm)

Type of LEV Area of face (ft2) Range Mean Effective 

capture of 

smoke?

Oven canopy exhaust hood 

Damper on gluing station LEV closed 4.0 5–80 45 Yes

Damper on gluing station LEV open 4.0 2–40 23 No

Gluing station flex-tube exhaust vent

Damper on oven LEV closed 2.6 335–400 377 Yes

Damper on oven LEV open 2.6 200–240 226 No

Nuisance odors were evident in the shell dipping and gluing and 

oven curing areas. Moving the flex-tube exhaust vent inlet closer to 

the gluing station would result in more efficient capture of odors. 

Alternatively, the use of a slot ventilation system or a downdraft 

table would also provide better capture efficiency of contaminants 

in both areas. Additional information on these LEV hood designs 

can be found in the ACGIH publication “Industrial Ventilation: A 

Manual of Recommended Practice for Design” [ACGIH 2010b].
Health Hazard Evaluation Report 2009-0070-3137 Page 7

Air sampling did not identify exposures over OELs to chemicals 

used in the gluing and oven curing or shell dipping areas. An 

evaluation of the LEV systems showed ineffective capture of 

contaminants when both LEV system dampers were open. Also, 

the potential for dermal exposure to glue components and 

lubricant was observed.

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

below to create a more healthful workplace. We encourage the 

electronics manufacturer to use a labor-management health and 

safety committee or working group to discuss the recommendations 

in this report and develop an action plan. Those involved in 

the work can best set priorities and assess the feasibility of our 

recommendations for the specific situation at the electronics 

manufacturer. 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 

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 the recommendations below to improve the existing 

LEV systems in the gluing and oven curing area even though 

measured exposures to toluene and ethanol were low. 

Although these engineering controls may help to reduce 

nuisance odors in the gluing and curing and the shell 

dipping areas, it may be difficult to reduce concentrations 

of these chemicals to below odor thresholds. For all of these 

chemicals, our measurements were above odor thresholds 

but well below OELs, and are unlikely to cause health effects 

at the measured concentrations.

Conclusions

Recommendations
Page 8 Health Hazard Evaluation Report 2009-0070-3137

Recommendations

(continued) a. Move the adjustable dampers on the flex-tube exhaust 

vent at the gluing station and the canopy exhaust hood 

over the oven to the closed position when either of the 

LEV systems is not in use. This increases the capture 

efficiency of the LEV that is in use.

b. Move the flex-tube exhaust vent inlet closer to the 

gluing station for better capture efficiency. Alternatively, 

consider a redesign of the flex-tube exhaust vent that will 

provide better capture efficiency of contaminants such 

as a slot ventilation system or downdraft table. With any 

LEV design or modification, we recommend consulting 

with a licensed engineer familiar with industrial 

ventilation design.

c. Consider adding LEV in the shell dipping area if 

nuisance odors continue to be a problem. Possible 

designs could include a slot ventilation system or 

downdraft table.

Personal Protective Equipment

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. Prevent skin contact with toluene, ethanol, and isopropanol. 

When working with glue containing toluene and ethanol, 

glove materials such as Viton®, Barrier® (PE/PA/PE), 

Silver shield/4H® (PE/EVAL/PE) and Tychem® CPF3 

should provide greater than 8 hours of dermal protection 

[Forsberg and Mansdorf 2007]. For isopropanol, all of 

the gloves types listed above can be used as well as some 

others including, butyl rubber, neoprene rubber, nitrile 

rubber, Viton®/butyl rubber, Tychem® F, and Tychem® 

Responder®. These glove materials should provide greater 
Health Hazard Evaluation Report 2009-0070-3137 Page 9

Recommendations

(continued) than 8 hours of dermal protection [Forsberg and Mansdorf 

2007]. The recommendation for use of neoprene and nitrile 

rubber gloves is not valid for gloves that are 3 millimeters or 

less in thickness.

2. Ensure that employees who voluntarily wear filtering 

facepiece respirators are provided with a copy of Appendix 

D of the OSHA Respiratory Protection Standard [29 

CFR 1910.134] titled “Information for Employees Using 

Respirators When Not Required Under the Standard.” 

Additionally, the OSHA Small Entity Compliance Guide 

provides guidance on voluntary respirator usage and 

additional information on respiratory protection at http://

www.osha.gov/Publications/secgrev-current.pdf.

ACGIH [2010a]. 2010 TLVs® and BEIs®: threshold limit values 

for chemical substances and physical agents and biological 

exposure indices. Cincinnati, OH: American Conference of 

Governmental Industrial Hygienists.

ACGIH [2010b]. Industrial ventilation: a manual of recommended 

practice for design. 27th ed. Cincinnati, OH: American 

Conference of Governmental Industrial Hygienists, pp. 6-1–6-40.

AIHA [1989]. Odor thresholds for chemicals with established 

occupational health standards. Fairfax, VA: American Industrial 

Hygiene Association, Table 5.3.

ASHRAE [2007]. Industrial local exhaust systems. In: 2007 

ASHRAE Handbook - HVAC Applications. I-P Edition. Atlanta, 

GA: American Society for Heating, Refrigerating, and AirConditioning Engineers, Inc., p. 30.2, Table 1.

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

Government Printing Office, Office of the Federal Register.

Forsberg K, Mansdorf SZ [2007]. Quick selection guide to chemical 

protective clothing. 5th ed. Hoboken, NJ: John Wiley & Sons, Inc., 

pp. 132, 135, 137.

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

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

References
Page 10 Health Hazard Evaluation Report 2009-0070-3137

References (continued) 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: June 

2011.
Health Hazard Evaluation Report 2009-0070-3137 Page 11

Air Sampling for Toluene, Ethanol, and Isopropanol

During the first site visit on February 23, 2009, sampling for toluene and ethanol was conducted using

Drägertube® colorimetric detection tubes attached to a handheld accuro® pump (Dräger, Lübeck, 

Germany). Toluene samples were collected on Toluene 5/b tubes (standard measuring range is 5–300 

ppm); ethanol samples were collected on Alcohol 25/a tubes (standard measuring range is 25–2000 ppm).

During the second visit on June 18, 2009, SKC Pocket Pumps® (SKC Incorporated, Eighty Four, 

Pennsylvania) were used for drawing airflows of 20, 50, and 200 cubic centimeters per minute through 

the sampling media, depending on the type of sample collected. All pumps were precalibrated and 

postcalibrated with the sampling media connected. Toluene samples were collected on SKC charcoal 

tubes (100 mg/50 mg) (SKC 226-01, lot 2000) and analyzed using NIOSH Method 1501 modified for 

gas chromatography/mass spectrometry [NIOSH 2010]. Ethanol samples were collected on SKC Anasorb 

747 tubes, parts A and B (SKC 226-82, Lot 5414) and analyzed using OSHA Method 100 [OSHA 2010]. 

Isopropanol samples were collected on SKC charcoal tubes (100 mg/50 mg) (SKC 226-01, lot 2000) and 

analyzed using NIOSH Method 1400 [NIOSH 2010].

Colorimetric Surface Sampling 

LeadCheck® colorimetric swabs (Hybrivet Systems, Incorporated, Natick, Massachusetts) were used to 

determine the presence of lead on the surface of the electrical shells. The swab is activated by crushing 

two ampoules within the swab, which moistens a wick on the end of the swab. The moistened wick is 

brushed onto a surface and turns red upon the presence of lead in surface concentrations greater than 1 

microgram. Swabs were brushed over the interior and exterior surfaces of the electrical shells. Swabs were 

also brushed onto a confirmation card that was provided with the swabs. This confirmation card contains 

a small amount of lead, and confirms that the colorimetric swabs are working correctly.

Ventilation Measurements 

A TSI VelociCalc® Plus air velocity meter, model 8386A (TSI, Inc, Shoreview, Minnesota) was used to 

measure air velocity at the face of the LEV. Air velocity measurements were collected at approximately 

3-inch intervals across the face of the gluing station flex-tube exhaust vent, and at approximately 8-inch 

intervals across the oven canopy exhaust hood. The capture efficiency of these LEV systems was also 

evaluated using irritant smoke tubes (Gastec Corporation, Kanagawa, Japan). To visualize the capture 

efficiency, smoke was generated in the work area where contaminants were to be generated. 

Appendix A: Methods
Page 12 Health Hazard Evaluation Report 2009-0070-3137

Appendix A: Methods (continued)

References 

NIOSH [2010]. 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 96135, 2nd Supplement Publication 98-119; 3rd Supplement 

2003-154. [http://www.cdc.gov/niosh/nmam/] Date accessed: June 2011.

OSHA [2010]. OSHA sampling and analytical methods. Hendricks W, ed. Salt Lake City, UT: U.S. 

Department of Labor, Occupational Safety and Health Administration. [http://www.osha.gov/dts/sltc/

methods/index.html] Date accessed: June 2011.
Health Hazard Evaluation Report 2009-0070-3137 Page 13

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 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 

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 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 adverse 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 at which adverse 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. The short-term exposures 

represent conditions to which workers can be exposed continuously for a short period of time without 

suffering acute effects such as (1) irritation; (2) chronic or irreversible effects; (3) dose-rate dependent 

toxic effects; or (4) narcotic effects that may cause accidental injury, impaired self rescue, or reduced work 

efficiency [ACGIH 2010].

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 of 1970. 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 2010]. 

Appendix B: Occupational Exposure Limits and Health Effects
Page 14 Health Hazard Evaluation Report 2009-0070-3137

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

WEELs have been established for some chemicals “when no other legal or authoritative limits exist” 

[AIHA 2010].

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

include both 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/

en/gestis/limit_values/index.jsp, contains international limits for over 1,500 hazardous substances and is 

updated periodically.

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 assessments 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.

Health Effects of Organic Solvents 

Organic solvents are a large class of chemicals that contain carbon and have a sufficiently high vapor 

pressure to allow some of the compound to exist in the gaseous state at room temperature. These chemical 

compounds are commonly used for tasks such as cleaning, painting, printing, degreasing, thinning, 

and extraction. OELs exist for some individual organic solvents, but do not exist for organic solvents as 

a group. Some of the organic solvents used in this facility include toluene, ethanol, and isopropanol. 

Toluene and ethanol are ingredients in the glue used to secure contacts to the electrical shells. Isopropanol 

is used to clean the rubber inserts before placing them into the electrical shells.
Health Hazard Evaluation Report 2009-0070-3137 Page 15

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

Inhalation and dermal exposure are important routes of exposure to organic solvents in the workplace. 

Absorption through the skin depends upon the degree of lipid and water solubility of the solvent 

[Rosenberg et al. 1997]. Almost all organic solvents cause irritation of the skin because they remove fat 

from the skin. Solvents are also among the leading causes of occupational skin disease [Cone 1986]. 

Organic solvents may cause minimal to mild irritation of the respiratory system [Blanc et al. 1991]. This 

irritation is usually restricted to the upper airways, mucous membranes and eyes, and it generally resolves 

quickly without long-term effects [Rosenberg et al. 1997].

Almost all volatile organic solvents can acutely cause nonspecific central nervous system depression. The 

symptoms of significant acute solvent exposure are similar to those from drinking too many alcoholic 

beverages, including headache, nausea and vomiting, dizziness, slurred speech, impaired balance, poor 

concentration, disorientation, and confusion. These symptoms go away quickly upon cessation of exposure 

[Gerr and Letz 1998]. Peripheral neuropathies and chronic central nervous system disorders (organic 

affective syndrome and mild chronic toxic encephalopathy) have been reported among workers chronically 

exposed to solvents [NIOSH 1987]. Organic affective syndrome is characterized by fatigue, memory 

impairment, irritability, difficulty in concentration, and mild mood disturbance.

References 

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

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

Industrial Hygienists.

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

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

Blanc PD, Galbo M, Hiatt P, Olson KR [1991]. Morbidity following acute irritant inhalation in a 

population-based study. JAMA 266(5):664–669.

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

Federal Register. 

Cone JE [1986]. Health hazards of solvents. Occup Med: State of the Art Reviews 1(1):69–87.

Gerr F, Letz R [1998]. Organic Solvents. Chapter 78. In: Rom WN, ed. Environmental and occupational 

medicine, 3rd rev. ed. Philadelphia, PA: Lippincott-Raven Publishers, pp.1091–1108.

NIOSH [1987]. Current intelligence bulletin 48: organic solvent neurotoxicity. Cincinnati, OH: 

U.S. Department of Health and Human Services, Centers for Disease Control, National Institute 

for Occupational Safety and Health, DHHS (NIOSH) Publication no. 87-104. [http://www.cdc.gov/

niosh/87104_48.html]. Date accessed: June 2011.
Page 16 Health Hazard Evaluation Report 2009-0070-3137

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

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: June 2011.

Rosenberg J, Cone JE, Katz EA [1997]. Solvents. In: LaDou J, ed. Occupational and environmental 

medicine, 2nd rev. ed. Stamford, CT: Appleton and Lange, pp. 483–513.
Health Hazard Evaluation Report 2009-0070-3137 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.

Mention of any company or product does not constitute 

endorsement by NIOSH. In addition, citations to websites 

external to NIOSH do not constitute NIOSH endorsement of 

the sponsoring organizations or their programs or products. 

Furthermore, NIOSH is not responsible for the content of these 

websites. All Web addresses referenced in this document were 

accessible as of the publication date.

This report was prepared by R. Todd Niemeier of HETAB, 

Division of Surveillance, Hazard Evaluations and Field Studies. 

Industrial hygiene field assistance was provided by Robert 

McCleery. 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 the electronics manufacturer, the state 

health department, and the Occupational Safety and Health 

Administration Regional Office. This report is not copyrighted and 

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

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

National Technical Information Service at 5825 Port Royal Road, 

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

NIOSH [2011]. Health hazard evaluation report: evaluation of exposure to toluene, 

ethanol, and isopropanol at an electronics manufacturer – Ohio. By Niemeier 

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

Disease Control and Prevention, National Institute for Occupational Safety and 

Health, NIOSH HETA No. 2009-0070-3137.

To receive NIOSH documents or information about 

occupational safety and health topics, contact NIOSH at:

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

TTY: 1-888-232-6348

E-mail: cdcinfo@cdc.gov

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

For a monthly update on news at NIOSH, subscribe to 

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

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