NIOSH HEALTH HAZARD EVALUATION REPORT:

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

HETA #2002-0379-2901

Superior Label Systems

Mason, Ohio

May 2003

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/reports

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/reports

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.

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/reports
ii

PREFACE

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 (OSHA) 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 company names or products does not constitute endorsement

by NIOSH.

ACKNOWLEDGMENTS AND AVAILABILITY OF REPORT

This report was prepared by Gregory Burr, Mark Methner, PhD, CIH, and Elena Page, MD of HETAB,

Division of Surveillance, Hazard Evaluations and Field Studies (DSHEFS). Field assistance was provided

by Lynda Ewers and Bradley King of DSHEFS. Analytical support was provided by DataChem Laboratories

and Ardith Grote, a NIOSH research chemist with the Division of Applied Research Technology. Desktop

publishing was performed by Robin Smith. Review and preparation for printing were performed by Penny

Arthur.

Copies of this report have been sent to employee and management representatives at Superior Label Systems,

Inc., and the OSHA Regional Office. This report is not copyrighted and may be freely reproduced. Single

copies of this report will be available for a period of three years from the date of this report. To expedite your

request, include a self-addressed mailing label along with your written request to:

NIOSH Publications Office

4676 Columbia Parkway

Cincinnati, Ohio 45226

800-356-4674

After this time, copies may be purchased from the National Technical Information Service (NTIS) at 5825

Port Royal Road, Springfield, Virginia 22161. Information regarding the NTIS stock number may be

obtained from the NIOSH Publications Office at the Cincinnati address.

For the purpose of informing affected employees, copies of this report shall be

posted by the employer in a prominent place accessible to the employees for a period

of 30 calendar days.
iii

Highlights of the NIOSH Health Hazard Evaluation

A Follow-up Evaluation of Visual Disturbances

Related to Amine Exposure

In 2001, NIOSH performed a health hazard evaluation (HHE) at Superior Label Systems, Inc.,

(SLS) because some employees were having blurry vision at work. NIOSH investigators took air

samples, had workers complete questionnaires, and performed eye examinations. We found that

employees had work-related vision problems which were associated with two chemicals S

dimethylisopropanolamine (DMIPA) and dimethylaminoethanol (DMAE). The company stopped

using DMIPA and employee complaints decreased. A follow-up survey was conducted in August

2002 to determine how DMIPA and DMAE levels in the air had changed and whether employees

no longer had blurry vision. 

What NIOSH Did

# We took air samples of 2 chemicals, DMIPA

and DMAE.

# We sampled the day and night shift employees

in the line and prime divisions over a two day

period.

# We asked these employees if they were having

blurry vision at work.

What NIOSH Found

# None of the 40 employees that we spoke with

in either the line or prime divisions had blurry

vision at work.

# There was little to no DMIPA in the air in

either

the line or prime divisions.

# There was DMAE in the air, but the amounts

were lower than those measured in the first

NIOSH survey.

# As in the first NIOSH survey, DMAE

concentrations were higher in the prime

division than in the line division. 

# Visual complaints stopped after management

began to dilute pH adjuster (which contains

DMIPA) with water.

# The company had improved the ventilation in

the line and prime divisions by keeping the

exhausted air from re-entering the building.

What To Do For More Information:

We encourage you to read the full report. If you

would like a copy, either ask your health and

safety representative to make you a copy or call

1-513-841-4252 and ask for

 HETA Report #2002-0379-2901

Highlights of the HHE Report
iv

Health Hazard Evaluation Report 2002-0379-2901

Superior Label Systems, Mason, Ohio

May 2003 

Gregory A. Burr, CIH

Elena H. Page, M.D., M.P.H.

Mark Methner, PhD, CIH

SUMMARY

In January 2001, the National Institute for Occupational Safety and Health (NIOSH) received a health hazard

evaluation (HHE) request from Superior Label Systems, Inc., (SLS) Mason, Ohio, a large flexographic

printing operation for consumer product labels. Employees in the line division were experiencing intermittent

blurred vision, while those in the adjacent prime division had few vision complaints. Workers and

management had been unable to associate these visual changes with any particular substance in use. NIOSH

investigators conducted medical questionnaires, eye exams, and personal breathing-zone (PBZ) sampling for

two amines used in the label printing process, dimethylisopropanolamine (DMIPA) and

dimethylaminoethanol (DMAE). The mean time-weighted average (TWA) concentration of DMIPA was

significantly higher in the line division than in the prime division (7.8 milligrams per cubic meter [mg/m3

]

vs. 1.9 mg/m3

, p<0.01), as was the mean TWA concentration for total amines (10 mg/m3 vs. 5.1 mg/m3,

p<0.01). Conversely, the mean TWA concentration of DMAE was significantly higher in the prime division

than the line division (3.2 mg/m3

 vs. 2.3 mg/m3, p<0.01). Exposures to these amines were associated with

visual and ocular changes and NIOSH investigators notified SLS management that the pH adjuster, which

contained DMIPA, may be responsible for workers’ visual complaints. The SLS management promptly

began diluting the pH adjuster, which contained DMIPA, and eventually replaced it with a product containing

only DMAE. This appeared to result in a resolution of visual complaints among the workers.

In August 2002, NIOSH investigators returned to SLS for additional air sampling for DMIPA and DMAE

to determine how exposures had changed since eliminating the use of the pH adjuster. We also asked

employees if they were having blurry vision at work. A total of 64 PBZ air samples were collected on 40

day- and evening-shift employees in the line and prime divisions over a two-day period. Trace concentrations

of DMIPA (between 0.06 and 0.2 mg/m3

) were measured on 16 PBZ samples; no DMIPA was detected on

the remaining 48 samples. DMAE concentrations ranged from 0.02 to 4.5 mg/m3

 in the line division and from

0.71 to 5.0 mg/m3

 in the prime division. Overall, DMIPA concentrations in both the prime and line divisions

sharply decreased between the initial and follow-up surveys, while DMAE concentrations remained relatively

unchanged. The continued presence of DMAE was not unexpected since DMAE was still used in both areas.

No blurry vision or other visual problems were reported by any interviewed workers.

A health hazard related to the use of DMIPA and DMAE no longer exists at this facility. The

continued use of DMAE, and the accompanying lower total amine concentrations, do not appear to

be causing any visual problems among the workers. A recommendation was made to continue

covering all open 5-gallon ink pails to reduce chemicals vaporizing into the work environment.

Keywords: SIC Code 2759 (Commercial Printing, Not Elsewhere Classified), blurry vision, halo vision,

cornea, amines, tertiary amines, dimethylaminoethanol, dimethylisopropanolamine, DMIPA, DMAE. 
TABLE OF CONTENTS

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Acknowledgments and Availability of Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Highlights of the HHE Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

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

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

Initial Survey (Feb.- May 2001) ..................................................... 1

Follow-up Survey (Aug. 2002) ...................................................... 1

Background ........................................................................ 1

Facility and Process Description ..................................................... 1

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

Industrial Hygiene Evaluation ....................................................... 2

Initial Survey (Feb.- May 2001) .................................................. 2

Follow-up Survey (Aug. 2002) ................................................... 3

Evaluation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Amines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

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

Industrial Hygiene Evaluation ....................................................... 4

Air Sampling - Initial Survey .................................................... 4

Air Sampling - Follow-up Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Medical Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Initial Survey ................................................................. 4

Follow-up Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Initial Survey ................................................................. 5

Follow-up Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Health Hazard Evaluation Report No. 2002-0379-2901 Page 1

INTRODUCTION

Initial Survey (Feb.- May 2001)

In January 2001 the National Institute for

Occupational Safety and Health (NIOSH) received

a request for a health hazard evaluation (HHE)

from Superior Label Systems, Inc., (SLS) Mason,

Ohio. Employees in the line division were

reporting intermittent blurred vision, described as

looking through a fog or a mist. It was most

noticeable when looking at lights, causing a halo

appearance. These visual changes, which

occurred on an intermittent basis, typically

resolved within a few hours after leaving work.

Workers and management had not been able to

associate these visual changes with any particular

substance in use. The symptoms were reported

only by employees in the line division of the plant,

only on Mondays through Thursdays, and not on

weekends when production was lower. 

Site visits were conducted on April 23-26 and

April 30-May 3, 2001, during which medical

questionnaires, eye exams, and extensive

industrial hygiene monitoring were performed.

Study participants were notified of the results of

their eye examinations at the end of each shift.

NIOSH investigators concluded that exposure to

two tertiary amines, dimethylaminoethanol

(DMAE) and dimethylisopropanolamine

(DMIPA), was associated with blurry, halo, and

blue-grey vision, corneal opacity, and decrements

in visual acuity and contrast sensitivity. The reentry of exhausted air was also identified as a

potential problem, and NIOSH concluded that the

ventilation in the line division was not adequate.

In addition to immediately reducing the amount of

DMIPA used in the line and prime printing

divisions, the company had also begun ventilation

improvements to prevent re-entrainment of

exhaust air. The company and NIOSH

investigators suspected that DMIPA was likely the

primary cause of the vision problems experienced

by the workers since higher concentrations of

DMIPA were measured in the line division

compared to the prime division. Eventually the

company replaced the DMIPA-containing product.

A more complete discussion of these findings is

contained in HETA 2001–144–2867.1

Follow-up Survey (Aug. 2002)

NIOSH investigators received an HHE request

from SLS management in August 2002 to reevaluate the line and prime divisions and

determine if process changes implemented by the

company, such as eliminating the use of DMIPA,

had reduced the amine exposures. A follow-up

survey was conducted on August 21-22, 2002,

during which industrial hygiene monitoring for

DMAE and DMIPA was performed. During this

follow-up survey employees were also asked if

they were currently experiencing blurry vision at

work. Based on the results of employee

interviews from the initial survey, NIOSH

investigators found that reporting of blurry vision

was usually the indicator of other vision problems.

BACKGROUND

Facility and Process

Description

Aside from the elimination of DMIPA from the

printing process, little had changed in the

production areas at SLS in the time between the

two surveys. With about 360 employees in four

facilities located in Ohio, Texas, and Arizona, this

company is one of the largest flexographic

printing operations for consumer product labeling

in the United States. The Ohio label production

plant, which opened in 1995, has approximately

100 production workers and about 78,000 square

feet (ft2

) of floor area. It operates two ten-hour

shifts on Monday through Thursday. There are

three primary jobs in the production areas: press

operators, rewinder operators, and press assistants.

There are skeleton crews working on Friday

through Sunday. 
Page 2 Health Hazard Evaluation Report No. 2002-0379-2901

Labels are printed on paper or plastic materials

using water-based, ultraviolet (UV)-cured, and

flourescent inks. The production area is divided

into two parts, the line division and the prime

division. The line division, with approximately

15,000 ft2

, has eight high-speed printing presses

using primarily water-based inks for printing less

detailed labels such as those used on milk and

orange juice containers. There is occasional use

of fluorescent inks, but no use of UV inks. The

prime division, with approximately 9000 ft2

, has 7

lower speed printing presses using mainly waterbased inks to print more detailed labels such as

those found on cosmetic and automotive products.

UV and fluorescent inks are also used in the prime

division. Presses in each division use 5-gallon

pails for holding inks before they are pumped to

ink troughs. 

The water-based inks contain 1% DMAE and,

depending on the specific ink, varying

concentrations of ammonia, isopropyl alcohol, and

glycol ether. During the initial survey clean print

additive (a compound containing 45% DMAE and

55% water) was used mainly on the prime side to

increase drying time on the inks.a

 A compound

referred to as pH adjuster (containing DMIPA)

was used daily in the line division. At the

conclusion of the initial NIOSH survey the pH

adjuster was suspected to be associated with the

visual complaints among the workers. As a result,

the company immediately began diluting the pH

adjuster with water, and eventually replaced it

with the DMAE-containing clean print additive.

Along with these two tertiary amines, both the line

and the prime divisions use adhesives and UV

varnishes for overprint laminating. In addition,

various cleaning agents, including alcohol,

ammonia, ethyl acetate, 2-butoxyethanol, and mild

soap and water, are routinely used to clean inks,

varnishes, and adhesives on presses and other

equipment. Air sampling conducted during the

initial survey for these chemicals measured very

low concentrations. 

METHODS

Industrial Hygiene Evaluation

Initial Survey (Feb.- May 2001)

Initial characterization sampling by NIOSH

investigators showed the most abundant

compounds were DMIPA, DMAE, ethyl acetate,

ammonia, ethanol, and isopropyl alcohol. DMIPA

concentrations were higher in the line division

than in the prime division, while DMAE was

present in similar concentrations in both areas.

DMIPA and DMAE were selected for further

monitoring for the following reasons: (1) they

were the most abundant airborne compounds

identified; (2) other similar amine compounds

were known to cause visual disturbances

consistent with those reported by SLS workers;

and (3) no other chemicals present in the plant

were known to cause such visual disturbances.

The sampling method used was a modification of

NIOSH Manual of Analytical Methods (NMAM)

No. 2007.b

 Although the original method called

for a silica gel sorbent tube, a NIOSH laboratory

desorption study found that DMIPA and DMAE

were recovered at the highest rate from XAD-7

tubes. A total of 108 full-shift personal breathingzone (PBZ) air samples were collected to assess

workers’ full-shift exposures in the line and prime

divisions to DMIPA and DMAE. Each sample

was collected on a XAD-7 tube connected to air

sampling pumps pre- and post-calibrated at 100

cubic centimeters of air per minute (cc/min). In

accordance with the modified NMAM No. 2007,

analysis for both DMIPA and DMAE was by gas

chromatography (GC) equipped with a flame

ionization detector (FID). Using this method, the

limit of detection for DMAE and DMIPA was 0.6

and 0.3 microgram per sample (μg/sample),

a Clean print additive is currently used in both the

prime and line divisions. 

b The reliability of NMAM No. 2007 had been in

question because of a history of yielding non-detectable

results even when amine compounds were present.
Health Hazard Evaluation Report No. 2002-0379-2901 Page 3

respectively. The limit of quantification for

DMAE and DMIPA was 20 and 10 μg/sample,

respectively.

Follow-up Survey (Aug. 2002)

As in the initial survey, PBZ air samples were

collected for DMIPA and DMAE in accordance

with the modified NMAM No. 2007. Samples

were collected on XAD-7 sorbent tubes (sampling

flow rate of 100 cc/min) and analyzed by GC-FID.

A total of 64 samples were collected in the line

and prime divisions over two consecutive days

during the first and second shifts. 

EVALUATION CRITERIA

As a guide to the evaluation of the hazards posed

by workplace exposures, NIOSH field staff

employ environmental evaluation criteria for the

assessment of a number of chemical and physical

agents. These criteria are intended to suggest

levels of exposure to which most workers may be

exposed up to 10 hours per day, 40 hours per week

for a working lifetime without experiencing

adverse health effects. It is, however, important to

note that not all workers will be protected from

adverse health effects even though their exposures

are maintained below these levels. A small

percentage may experience adverse health effects

because of individual susceptibility, a pre-existing

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 worker to

produce health effects even if the occupational

exposures are controlled at the level set by the

criterion. These combined effects are often not

considered in the evaluation criteria. Also, some

substances are absorbed by direct contact with the

skin and mucous membranes, and thus potentially

increase the overall exposure. Finally, evaluation

criteria may change over the years as new

information on the toxic effects of an agent

become available.

The primary sources of environmental evaluation

criteria for the workplace are: (1) NIOSH

Recommended Exposure Limits (RELs),2

 (2) the

American Conference of Governmental Industrial

Hygienists’ (ACGIH®) Threshold Limit Values

(TLVs®),3

 and (3) the U.S. Department of Labor,

Occupational Safety and Health Administration

(OSHA) Permissible Exposure Limits (PELs).4

Employers are encouraged to follow the OSHA

limits, the NIOSH RELs, the ACGIH TLVs®, or

whichever is the more protective criterion.

OSHA requires an employer to furnish employees

a place of employment that is free from

recognized hazards that are causing 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,

employers should understand that not all

hazardous chemicals have specific OSHA

exposure limits such as PELs and short-term

exposure limits (STELs). An employer is still

required by OSHA to protect their employees

from hazards, even in the absence of a specific

OSHA PEL.

A time-weighted average (TWA) exposure refers

to the average airborne concentration of a

substance during a normal 8- to 10-hour workday.

Some substances have recommended STEL or

ceiling values which are intended to supplement

the TWA where there are recognized toxic effects

from higher exposures over the short-term.

Amines

Aliphatic amines are ammonia derivatives in

which an alkyl or alkanol group replaces one or

more hydrogen atoms. They are classified as

primary, secondary, or tertiary amines and are

used as solvents, chemical intermediates, catalysts,

preservatives, and in drugs and herbicides.5

 The

tertiary amines can be irritants to both the skin and

mucous membranes. Systemic symptoms related

to inhalational exposure to tertiary amines include

headache, nausea, and faintness. A number of

reports describe blurred vision, halo vision, or

blue-grey vision (glaucopsia) among persons
Page 4 Health Hazard Evaluation Report No. 2002-0379-2901

exposed to a variety of amines. In all published

reports, these effects have been reversible.

Proposed mechanisms for the visual changes

include swelling of the cornea or dilation of the

pupil and paralysis of the ciliary muscle.6

No reports were found of humans experiencing

visual disturbances after exposure to DMAE, the

tertiary amine still present in the inks at SLS.

However, animal experiments did document

corneal opacification, corneal edema, and

ulcerative keratitis at exposures greater than 861

milligrams per cubic meter (mg/m3

).7 Exposure to

71.8 mg/m3

 of DMAE resulted in corneal opacity

in animals that regressed during non-exposure

periods.7

 DMIPA, the primary component of the

pH adjuster that is no longer used at SLS, had not

been reported to cause visual disturbances in

humans. There are no occupational exposure

limits for either DMIPA or DMAE.

RESULTS

Industrial Hygiene Evaluation

Air Sampling - Initial Survey

As shown in Table 1, the mean TWA

concentrations of DMIPA were significantly

higher in the line division than in the prime

division (7.8 mg/m3

 vs. 1.9 mg/m3, p<0.01), as

was the mean TWA concentration for total amines

(10 mg/m3

 vs. 5.1 mg/m3, p<0.01). Conversely,

the mean TWA concentration of DMAE was

significantly higher in the prime division than the

line division (3.2 mg/m3

 vs. 2.3 mg/m3, p<0.01). 

Air Sampling - Follow-up Survey

As shown in Table 1, only trace concentrations of

DMIPA (between 0.12 to 0.40 mg/m3

) were

measured in either division. In contrast, DMAE

was still present in both the line and prime

divisions, with the mean TWA concentrations of

DMAE higher in the prime division than in the

line (3.1 mg/m3

 vs. 0.76). This was not surprising

considering that clean print additive, which

contains DMAE, was still used in both areas.

Appendix A contains all of the individual sample

data collected during both the follow-up surveys.

Medical Evaluation 

Initial Survey

Of the 36 line workers who completed

questionnaires, 32 (89%) reported having

experienced blurry vision while at work in the past

12 months, compared to 3 of 24 (12.5%) of the

prime workers (p<0.01). Findings were similar

for halo and blue-grey vision. Symptoms

developed an average of 4.3 hours after the start of

the shift. NIOSH investigators also found

episodes of corneal opacity, decreased bilateral

visual acuity, decreased bilateral contrast

sensitivity (at 2.5% and 1.25% contrast), and

increased corneal thickness. In all instances of

corneal opacity, there was complete clearing by

the beginning of the worker’s next shift.

There was a positive association between reported

visual symptoms, corneal opacity, and corneal

thickness and increasing concentrations of total

amines (calculated by summing the DMIPA and

DMAE concentrations). Findings were similar

when looking at each amine individually. Since

concentrations of the two chemicals were highly

correlated to one another, it was not possible to

determine by statistical analysis if exposure to

only DMIPA or DMEA was responsible for the

visual problems experienced by the workers.

Follow-up Survey

All 40 employees in the line and prime divisions

who agreed to PBZ air sampling were asked if

they were having blurry vision which they felt

may be work related. No visual problems were

reported by any of the interviewed workers.

DISCUSSION
Health Hazard Evaluation Report No. 2002-0379-2901 Page 5

There have been case reports of blurry, halo,

and/or blue grey vision, increased corneal

thickness, corneal edema, and decrements in

visual acuity and contrast sensitivity among

workers exposed to a variety of amines.8,9,10 In the

initial survey, NIOSH investigators documented

an association between these symptoms and TWA

exposure to two tertiary amines, DMAE and

DMIPA. Neither of these amines, however, had

previously been reported to cause visual

disturbances in humans.

A follow-up survey was conducted since DMAE

and DMIPA concentrations measured in the first

study were highly correlated, making it difficult

to separate their effects. However, DMIPA was

believed to be causing the visual changes in this

group of workers for the following reasons:

1) Visual symptoms were more common in

the line division, where concentrations of

DMAE were significantly lower than in

the prime division.

2) Airborne DMIPA concentrations in the

line division were significantly higher that

in the prime division.

3) DMIPA, with a vapor pressure of 14.7

torr, is a more volatile chemical than

DMAE, which has a vapor pressure of

4.0 torr.11

4) Shortly after the initial NIOSH survey,

SLS began diluting the pH adjuster

(which contained DMIPA) with water.

This resulted in no visual complaints by

the workers.

Results from the follow-up survey supported the

hypothesis that DMIPA was the primary cause of

the vision problems. As shown in Figure 1,

DMIPA concentrations in both the prime and line

divisions decreased between the initial and followup surveys, while DMAE concentrations remained

relatively unchanged. This was not unexpected

since DMAE-containing compounds such as inks

and clean print additive are still used in both

divisions. Alternately, it is possible that the

concentration of total amines in the air was

responsible for the visual effects, and that since

DMIPA was present in higher concentrations, its

elimination significantly lowered the overall level.

CONCLUSIONS

In the first survey, exposure to amines at SLS had

been associated with blurry, halo, and blue-grey

vision, corneal opacity, and decrements in visual

acuity and contrast sensitivity. This follow-up

survey confirms that this hazard no longer exists

at SLS.

RECOMMENDATIONS

Initial Survey

Recommendations were made to cover open ink

containers in the line and prime divisions, reduce

the re-entrainment of exhaust air by the local

exhaust ventilation systems, and use gloves made

of butyl rubber that are impermeable to the amine

compounds as well as isopropyl alcohol,

ammonia, and 2-butoxyethanol used by workers.12

NIOSH investigators also recommended

additional industrial hygiene monitoring following

process changes or when new chemical products

(i.e., inks and additives) were introduced. This

last recommendation was part of the impetus for

conducting this follow-up evaluation. 
Page 6 Health Hazard Evaluation Report No. 2002-0379-2901

1. Page EH, Cook CK, Mueller, CA, Mortimer

V. Hazard evaluation and technical assistance

report: Superior Label Systems, Mason, Ohio.

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

Human Services, Public Health Service, Centers

for Disease Control and Prevention, National

Institute for Occupational Safety and Health,

NIOSH HETA No. 2001-0144-2867.

2. NIOSH [1992]. Recommendations for

occupational safety and health: compendium of

policy documents and statements. Cincinnati, OH:

U.S. Department of Health and Human Services,

Public Health Service, Centers for Disease Control

and Prevention, National Institute for

Occupational Safety and Health, DHHS (NIOSH)

Publication No. 92-100.

3. ACGIH [2001]. 2001 TLVs® and BEIs®:

threshold limit values for chemical substances and

physical agents. Cincinnati, OH: American

Conference of Governmental Industrial

Hygienists.

4. CFR [1997]. 29 CFR 1910.1000. Code of

Federal Regulations. Washington, DC: U.S.

Government Printing Office, Office of the Federal

Register.

5. Rosenberg, J, Cone JE, Katz EA [1997].

Solvents. Chapter 29. In: LaDou J, ed.

Occupational and environmental medicine. 2nd

rev. ed. Stamford, CT: Appleton and Lange, pp.

483-513. 

6. Albrecht WN, Stephenson RL [1988]. Health

hazards of tertiary amine catalysts. Scand J Work

Environ Health. 14:209-219. 

7. Klonne DR, Dodd DE, Pritts IM, Nachreiner

DJ, Fowler EH, Troup CM.et. al. [1987]. 

Dimethylethanolamine: acute, 2-week, and 13-

week inhalation toxicity studies in rats. Fundam

Appl Toxicol. 9:512-521. 

8. Ákesson B, Florén I, Skerfving S [1985].

Visual disturbances after experimental human

exposure to triethylamine. Br J. Ind Med.

42:848-50.

9. Jarvinen P, Engstrom K, Riihmaki V,

Ruusuvaara P, Setala K [1999]. Effects of

experimental exposure to triethylamine on vision

and the eye. Occup Environ Med. 56(1):1-5.

10. Stählbom B, Lundh T, Florén I, Åkesson B

[1991]. Visual disturbances in man as a result of

experimental and occupational exposure to

dimethylamine. Br J Ind Med. 48:26-29.

11. Ballantyne B, Leung H [1996]. Acute

toxicity and primary irritancy of

alkylalkanolamines. Vet Human Toxicol.

38(6):422-426.

12. Forsberg K, Mansdorf SZ [1997]. Quick

selction guide to chemical protective clothing,

3rd. rev. edition. New York, NY: John Wiley

and Sons, Inc.

Follow-up Survey

The company had implemented all of the

recommendations contained in the initial report.

NIOSH investigators did observe some uncovered

ink containers in the press areas, although the

number of open containers had declined from the

initial survey. Covering containers of inks and

other solvents will further reduce airborne

concentrations.

REFERENCES
Health Hazard Evaluation Report No. 2002-0379-2901 Page 7
Page 8 Health Hazard Evaluation Report No. 2002-0379-2901

Table 1

Comparison of Tertiary Amine Concentrations from Full-shift 

Personal Breathing-zone Samples Collected in in the Prime and Line Divisions, by Survey

Superior Label Systems, Inc.

Compound

Prime Division (mg/m3) P Line Division (mg/m3) P

Initial Survey

n=15

Follow-up Survey

n=18

Initial Survey

n=95

Follow-up Survey

n=46

Mean Range Mean Range Mean Range Mean Range

DMAE 3.2 1.7-4.2 3.1 0.71-5.0 2.3 0.18-4.5 0.72 0.02-4.5

DMIPA 1.9 0.86-2.9 0.16 0.05-0.37 7.8 0.66-17 0.06 0.04–0.29

Total 5.1 2.7-6.7 3.2 0.76-5.3 10 0.84-20 0.78 0.08-4.8

n = number of personal breathing-zone samples collected

# = concentration, expressed in milligrams per cubic meter

DMAE = dimethylaminoethanol

DMIPA = dimethylisopropanolamine

Total = sum of DMAE and DMIPA concentrations
Health Hazard Evaluation Report No. 2002-0379-2901 Page 9

Appendix A

Air Sampling Results for Amines - Follow-up Survey

Superior Labels System, Inc.

Sampling Date: August 21, 2002

Job Sampling Time

(minutes)

Sample

Volume (liters)

Concentration, mg/m3

DMAE DMIPA Total Amines

Line Division (Day Shift)

Packer 481 48.1 0.85 ND 0.91

Press Feeder 571 57.1 0.60 ND 0.66

Press Operator 569 56.9 1.1 Trace 1.2

Rewinder 483 48.3 0.85 ND 0.91

Packer 486 48.6 0.86 ND 0.92

Press Feeder 486 48.6 0.91 ND 0.97

Packer 461 46.1 0.65 ND 0.71

Shipping 457 45.7 0.39 ND 0.45

Utility Person 525 52.5 0.67 ND 0.73

Lead Man 273 27.3 0.29 ND 0.35

Press Operator 352 35.2 0.57 ND 0.63

Fan Folder 291 29.1 0.76 ND 0.82

Prime Division (Day Shift)

Press Operator 424 42.4 2.8 Trace 2.9

Press Operator 526 52.6 1.9 Trace 2.0

Press Operator 416 51.6 2.2 ND 2.3

Press Operator 518 51.8 2.1 Trace 2.2

Press Operator 350 35 1.9 ND 2.0

Minimum Detectable Concentration (MDC) 50 0.12 0.06 N/A

Minimum Quantifiable Concentration (MQC) 50 0.40 0.20 N/A

DMAE = dimethylaminoethanol DMIPA = dimethylisopropanolamine

ND = not detectable (below the MDC) Trace = between the MDC and MQC

Total = sum of DMEA and DMIPA N/A = not applicable

Note: For DMEA and DMIPA concentrations which fell between the MDC and MQC for this sample set, imputed

values were used based on either the MDC (for the not detected values) or the reported laboratory value (for

the Trace concentrations). For DMIPA, 0.06 mg/m3

 was used for ND values. For DMEA, 0.12 mg/m3 was

used for ND values. All concentrations have been rounded to two significant digits.
Page 10 Health Hazard Evaluation Report No. 2002-0379-2901

Appendix A (continued)

Air Sampling Results for Amines - Follow-up Survey

Superior Labels System, Inc.

Sampling Date: August 21, 2002

Job Sampling Time

(minutes)

Sample

Volume (liters)

Concentration, mg/m3

DMAE DMIPA Total Amines

Line Division (Night Shift)

Packer 611 61.1 0.46 ND 0.52

Packer 56 56 0.96 ND 1.0

Press Operator 562 56.2 1.4 ND 1.5

Press Operator 558 55.8 4.5 Trace 4.7

Press Operator 521 52.1 1.2 ND 1.3

Rewinder 516 51.6 0.91 ND 0.97

Press Operator 413 41.3 0.73 ND 0.79

Press Operator 488 48.8 1.3 ND 1.4

Press Operator 550 55 0.60 ND 0.66

Press Operator 537 53.7 1.1 ND 1.2

Press Operator 400 40 0.70 ND 0.76

Maintenance 569 56.9 1.0 ND 1.1

Press Operator 439 43.9 0.68 ND 0.74

Prime Division (Night Shift)

Press Operator 611 61.1 4.9 Trace 5.1

Packer 553 55.3 4.1 Trace 4.3

Press Operator 291 29.1 4.1 Trace 4.3

Press Operator 269 26.9 4.5 Trace 4.7

Minimum Detectable Concentration (MDC) 50 0.12 0.06 N/A

Minimum Quantifiable Concentration (MQC) 50 0.40 0.20 N/A

DMAE = dimethylaminoethanol DMIPA = dimethylisopropanolamine

ND = not detectable (below the MDC) Trace = between the MDC and MQC

Total = sum of DMEA and DMIPA N/A = not applicable

Note: For DMEA and DMIPA concentrations which fell between the MDC and MQC for this sample set, imputed

values were used based on either the MDC (for the not detected values) or the reported laboratory value (for

the Trace concentrations). For DMIPA, 0.06 mg/m3

 was used for ND values. For DMEA, 0.12 mg/m3 was

used for ND values. All concentrations have been rounded to two significant digits.
Health Hazard Evaluation Report No. 2002-0379-2901 Page 11

Appendix A (continued)

Air Sampling Results for Amines - Follow-up Survey

Superior Labels System, Inc.

Sampling Date: August 22, 2002

Job Sampling Time

(minutes)

Sample

Volume (liters)

Concentration, mg/m3

DMAE DMIPA Total Amines

Line Division (Day Shift)

Packer 657 65.7 Trace ND 0.46

Packer 795 79.5 Trace ND 0.46

Press Operator 389 38.9 1.1 ND 1.2

Packer 50 5.0 Trace ND 0.46

Fan Folder 335 33.5 Trace ND 0.46

Rewinder 513 51.3 Trace ND 0.46

Shipping 752 75.2 Trace ND 0.46

Lead Man 266 26.6 Trace ND 0.46

Press Operator 302 30.2 Trace ND 0.46

Press Operator 533 53.3 0.81 ND 0.87

Press Feeder 580 58 Trace ND 0.46

Press Feeder 541 54.1 Trace ND 0.46

Prime Division (Day Shift)

Press Operator 302 30.2 4.3 Trace 4.5

Press Operator 575 57.5 2.5 Trace 2.7

Press Operator 573 57.3 3.3 Trace 3.5

Press Operator 571 57.1 3.4 Trace 3.6

Press Operator 564 56.4 4.6 Trace 4.8

Minimum Detectable Concentration (MDC) 50 0.12 0.06 N/A

Minimum Quantifiable Concentration (MQC) 50 0.40 0.20 N/A

DMAE = dimethylaminoethanol DMIPA = dimethylisopropanolamine

ND = not detectable (below the MDC) Trace = between the MDC and MQC

Total = sum of DMEA and DMIPA N/A = not applicable

Note: For DMEA and DMIPA concentrations which fell between the MDC and MQC for this sample set, imputed

values were used based on either the MDC (for the not detected values) or the reported laboratory value (for

the Trace concentrations). For DMIPA, 0.06 mg/m3

 was used for ND values. For DMEA, 0.12 mg/m3 was

used for ND values. All concentrations have been rounded to two significant digits.
Page 12 Health Hazard Evaluation Report No. 2002-0379-2901

Appendix A (continued)

Air Sampling Results for Amines

Superior Labels System, Inc.

Sampling Date: August 22, 2002

Job Sampling Time

(minutes)

Sample

Volume (liters)

Concentration, mg/m3

DMAE DMIPA Total Amines

Line Division (Night Shift)

Press Operator 513 51.3 Trace ND 0.46

Packer 507 50.7 Trace ND 0.46

Press Operator 500 50 Trace ND 0.46

Rewinder 500 50 Trace ND 0.46

Press Operator 250 25 Trace ND 0.46

Packer 210 21 Trace ND 0.46

Press Operator 497 49.7 Trace ND 0.46

Press Operator 756 45.6 0.59 ND 0.46

Rewinder 501 50.1 Trace ND 0.46

Prime Division (Night Shift)

Press Operator 490 49 1.5 ND 1.6

Press Operator 490 49 3.2 ND 3.3

Press Operator 497 49.7 3.1 Trace 3.3

Packer 486 48.6 2.1 Trace 2.3

Minimum Detectable Concentration (MDC) 50 0.12 0.06 N/A

Minimum Quantifiable Concentration (MQC) 50 0.40 0.20 N/A

DMAE = dimethylaminoethanol DMIPA = dimethylisopropanolamine

ND = not detectable (below the MDC) Trace = between the MDC and MQC

Total = sum of DMEA and DMIPA N/A = not applicable

Note: For DMEA and DMIPA concentrations which fell between the MDC and MQC for this sample set, imputed

values were used based on either the MDC (for the not detected values) or the reported laboratory value (for

the Trace concentrations). For DMIPA, 0.06 mg/m3

 was used for ND values. For DMEA, 0.12 mg/m3 was

used for ND values. All concentrations have been rounded to two significant digits.
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Page 14 Health Hazard Evaluation Report No. 2002-0379-2901