Lighting, Indoor 

Environmental Quality 

Concerns, and Job 

Stress at a Call Center – 

California

Douglas M. Wiegand, PhD

Jessica G. Ramsey, MS, CPE

Gregory A. Burr, CIH

JungHo Choi, MS, CIH

Health Hazard Evaluation Report

HETA 2012-0081-3169

January 2013

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

Workplace

Safety and Health

 National Institute for Occupational 

Safety and Health
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

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

amended at 45 FR 2653, January 14, 1980].
Health Hazard Evaluation Report 2012-0081-3169 Page i

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

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

Summary .........................................................................................................v

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

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

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

Discussion.................................................................................................... 13

Conclusions................................................................................................. 16

Recommendations.................................................................................... 16

References.................................................................................................... 19

Contents

Acknowledgments Acknowledgments and Availability of Report................................ 27

Appendix A Tables............................................................................................................. 21

Appendix B Figures........................................................................................................... 24
Page ii Health Hazard Evaluation Report 2012-0081-3169

Abbreviations

AFGE American Federation of Government Employees

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

CDC Centers for Disease Control and Prevention

CO2 Carbon dioxide

cfm Cubic feet per minute

GSA General Services Administration

HHE Health hazard evaluation

IEQ Indoor environmental quality

NAICS North American Industry Classification System

NIOSH National Institute for Occupational Safety and Health

OSHA Occupational Safety and Health Administration

ppm Parts per million
Health Hazard Evaluation Report 2012-0081-3169 Page iii

The National Institute for 

Occupational Safety and 

Health (NIOSH) received 

a request for a health 

hazard evaluation from the 

local American Federation 

of Government Employees 

union. The request 

concerned indoor lighting, 

indoor environmental 

quality, and job stress at a 

call center in California.

Highlights of the

NIOSH Health

Hazard Evaluation What NIOSH Did

● We evaluated the call center on April 17–18, 2012.

● We measured the level of light indoors.

● We checked the ventilation systems.

● We measured the amount of air flowing out of the 

ceiling diffusers.

● We asked employees to fill out a survey. The survey asked 

about job stress, health and safety concerns, and other factors 

at work.

What NIOSH Found

● The level of light averaged 50.7 footcandles. This level met 

the requirements listed in the building lease.

● The current lighting design may have produced glare in 

some areas.

● The ventilation systems should be tested and balanced.

● Air was not evenly distributed to all areas of the call center.

● Job stress and employees’ concern for their health at work 

was moderately high. 

What Managers Can Do

● Evaluate the ventilation system and uneven airflow in pods B, 

C, and D. Then conduct a test and balance on the systems.

● Think about human perception and numerical standards 

when choosing lighting levels. 

● Try different lighting designs. Ask employees which one 

they prefer. 

● Start a health and safety committee. Managers, union 

representatives, and employees should all be part of this 

committee. 

● Create a way for employees to report workplace health and 

safety concerns. Make sure that employees are kept informed 

about progress and solutions for issues. 
Page iv Health Hazard Evaluation Report 2012-0081-3169

Highlights of the

NIOSH Health

Hazard Evaluation

 (continued)

 

● Give employees feedback that they can use to improve their 

communications with customers. Do not forget to provide 

positive feedback to employees on what they did well. 

● Ask employees to comment on processes and procedures 

being used in the call center. Listen to their suggestions on 

how things can be improved; this can improve employee 

morale and productivity.

● Encourage employees to debrief with their supervisor or 

a coworker immediately after a call with an unfriendly 

customer. This will help reduce employees’ stress levels and 

improve communication in the center.

● Encourage employees to take sick leave when they are ill or 

when they may be contagious.

● Talk to employees about workplace violence and workplace 

bullying. Train employees on ways to deal with stress.

What Employees Can Do

● Participate in health and safety meetings. If you have health 

or safety concerns you should report those at these meetings.

● Seek counseling if you experience symptoms of anxiety, 

anger, depression, or other mental health issues that affect 

you in occupational, social, or other settings. If these 

symptoms affect your daily life, you should get help. Seek 

care from a licensed clinical psychologist or psychiatrist.

● Report any suspicious behavior or expressions of violence to 

a supervisor immediately. 

● Keep your workstation at the proper settings. Computer 

monitors should be placed so that the top line of the screen 

is at or below eye level. Chairs should provide back support 

and allow feet to rest on the floor. These settings will reduce 

your risk of developing musculoskeletal disorders.
Health Hazard Evaluation Report 2012-0081-3169 Page v

Call center employees 

were concerned about 

indoor lighting, IEQ, and 

job stress. We found that 

the lighting was within 

the limits specified in the 

lease agreement. Lighting 

may need adjustment 

to account for glare and 

employee comfort. The 

ventilation system needs 

maintenance to balance 

the airflow. Employees 

should report their workrelated health concerns 

at joint management 

and employee safety 

committee meetings. 

Managers should follow 

up on all health and 

safety concerns raised 

by employees. To reduce 

stress, employees should 

talk to a supervisor or 

coworker immediately 

after working with an 

angry customer. 

Summary

In February 2012, the AFGE submitted an HHE request to 

NIOSH regarding indoor lighting, IEQ, and job stress at a call 

center in California. We evaluated the call center on April 17–18, 

2012. HHE Program investigators met with managers, local union 

representatives, and employees and observed work processes, 

practices, and workplace conditions throughout the call center. 

We measured illumination; examined the ventilation systems; 

and measured temperature, relative humidity, and carbon dioxide 

throughout the workday. We also administered a voluntary survey 

of employees to assess their health and safety concerns as well as 

their perceptions of the psychosocial work environment. 

We collected 53 light measurements throughout the call center. 

The light level averaged 50.7 footcandles, meeting the U.S. GSA 

illumination recommendations. However, luminance levels 

(commonly called brightness) in the employee’s field of view can 

cause glare. This glare may cause some of the visual discomfort 

reported by employees.

The CO2 concentrations in the call center ranged from 410 to 

635 ppm during this evaluation; outdoor concentrations were 

380 ppm. Indoor CO2 concentrations were similar to outdoor 

concentrations, suggesting that the call center ventilation was 

adequate. Temperature in the call center ranged from 68°F to 

76°F, and relative humidity ranged from 43% to 49%, compared 

to an outdoor temperature of 60°F to 71°F and relative humidity 

ranging from 49% to 54%. These values are within the ASHRAErecommended thermal comfort guidelines.

We measured airflow at 71 of 86 ceiling diffusers. Airflow ranged 

from 0 cfm to 917 cfm, demonstrating that supply air was not 

evenly distributed to all occupied areas of the call center by the 

ventilation systems. We were unable to measure airflow at all 

diffusers because of furniture or file cabinets blocking access.

We received 283 completed employee surveys (85% response 

rate) on job stress, work-related health and safety concerns, and 

psychosocial factors at work. Participants’ reported levels of job 

stress and concerns for their health at work were moderately 

high. Most participants reported very little concern for their own 

personal safety at work. Some employees indicated that they were 

concerned about being physically attacked by a member of the 

public on the building grounds or by another call center employee.
Page vi Health Hazard Evaluation Report 2012-0081-3169

Keywords: NAICS 923130 Administration of Human Resource 

Programs (except Education, Public Health, and Veterans’ Affairs 

Programs), call center, office building, IEQ, lighting, ventilation, job 

stress, psychosocial, cancer

To address job stress, work-related health and safety concerns, and 

psychosocial factors we recommended creating a joint management 

and employee health and safety committee. We also recommended 

that a system be created for employees to document health and 

safety concerns. Management should use this system to keep 

employees informed about how concerns are being addressed. 

Suggestions for ways to reduce job stress were also provided. 

We recommended testing and balancing the ventilation systems 

and modifying the lighting design policy to take employee 

perception and satisfaction into consideration. Management 

should look into different parabolic louver designs that may better 

control light into the work area and reduce glare for employees 

working nearby. A guard rail should be installed on the loading 

dock that is used as an employee break area.

Summary

 (continued)
Health Hazard Evaluation Report 2012-0081-3169 Page 1

Introduction

NIOSH received an HHE request from the local AFGE union 

representing employees at a telephone call center (call center) in 

California. The request concerned indoor lighting, IEQ, and job 

stress. Health effects described in the request included eye strain, 

headaches, colds, flu, and sneezing. NIOSH investigators evaluated 

the call center on April 17–18, 2012.

During the evaluation we met with managers, local union 

representatives, and employees to discuss the HHE request. 

Following an opening meeting, we observed work processes, 

practices, and workplace conditions in the call center. We 

measured illumination; examined the ventilation systems; and 

measured temperature, relative humidity, and CO2 throughout the 

workday. We also administered a voluntary survey to employees 

to assess their job stress, work-related health and safety concerns, 

and various psychosocial factors at work. On April 30, 2012, we 

sent an interim letter containing our preliminary findings and 

recommendations to the managers, local and national union 

representatives, and the building owner. 

Background

At the time of this evaluation 333 employees worked in the 

approximately 70,000 square foot call center. The carpeted call 

center occupied a single story masonry building constructed in the 

1970s in a suburban retail area. The building had a flat roof with 

a decorative tiled parapet. Ten air handling units and solar panels 

were located on the roof. A paved employee parking lot that was 

also accessible to the public was situated on three of the four sides 

of the call center. Employees could access a landscaped, open-air 

atrium in the middle of the call center during breaks. This atrium 

was not accessible to the general public.

Call center employees worked 8.5-hour shifts. The shift start times 

were staggered from 6:45 a.m. to 9:00 a.m. to accommodate calls 

from different time zones. Call center employees averaged about 

7 hours on either the phone or computer each shift answering 

questions from the public.

The building was divided into four sections called pods. Most 

employees worked from cubicles (fabric covered walls, partition 

height about 4 to 5 feet) in pods B, C, and D. Administrative 
Page 2 Health Hazard Evaluation Report 2012-0081-3169

Introduction

 (continued)

Assessment

offices, training rooms, a lunch room, and a health clinic (that 

was unoccupied during our evaluation) were located in pod A. 

We focused our evaluation on pods B, C, and D because that was 

where most of the employees worked.

We learned that until February 2012 employees could bring in 

a doctor’s note asking to have fluorescent bulbs removed from 

ceiling light fixtures above their workstation to reduce the light 

level. In February 2012, call center managers notified union 

officials and employees that all fluorescent bulbs in all ceiling light 

fixtures would be replaced and kept on to maintain the GSArequired minimum level of illumination.

We measured illumination in pods B, C, and D using a Sper 

Scientific light meter, Model 840020 (Sper Scientific Ltd., 

Scottsdale, Arizona). This light meter measures footcandles, a 

unit of illumination commonly used in the United States. A 

footcandle is the illumination on a one square foot surface area 

on which the light of one candela (essentially the light output of a 

candle) is uniformly distributed [Crouch 1978]. We took our light 

meter readings in occupied cubicles on the work surface directly 

in front of the keyboard. These work surfaces were positioned 

by the employees for either a sitting or standing workstation 

configuration; we did not change the configuration. 

We looked for evidence of water damage, water incursion, visible 

mold, and other potential IEQ problems in the call center. We 

took measurements for temperature, relative humidity (employee 

comfort indicators), and CO2 (an indicator of ventilation 

effectiveness) with a Q-TRAKTM Plus Indoor Air Quality Monitor, 

Model 8554 (TSI Incorporated, Shoreview, Minnesota). We 

visually inspected four of the ten rooftop air handling units that 

provided ventilation for the call center. To evaluate how supply 

air was distributed by the air handling units in the call center, we 

measured airflow with a TSI Model 8371 ventilation flow hood 

(TSI Incorporated, Shoreview, Minnesota). 

We distributed a self-administered, anonymous survey, along with 

instructions and information regarding participant confidentiality, 

to all employees’ (N = 333) desks the morning of April 17, 2012. 

The survey included scaled and open-ended items and covered 

participant demographics, job stress, work-related health and safety 
Health Hazard Evaluation Report 2012-0081-3169 Page 3

Assessment

 (continued) concerns, and psychosocial factors at work. Psychosocial factors at 

work were assessed in six domains: the physical work environment, 

job demands, job satisfaction, safety climate, perceived job control, 

and social support. Once complete, participants were asked to seal 

their anonymous survey in an envelope and return it directly to a 

NIOSH project officer.

Results Lighting Levels

We took 53 measurements, with results ranging from 

34 footcandles to 77.2 footcandles. The average measurement, 

50.7 footcandles, meets the GSA illumination recommendation 

of 50 average maintained footcandles at working surface height 

throughout the space. We measured illumination, the amount 

of light falling on a surface. We did not measure luminance 

(also called brightness), which is the amount of light coming 

toward the eye from an object(s). Brightness is a metric used to 

characterize emission or reflection from flat, diffuse surfaces. An 

uncomfortable level of brightness is described as glare. However, 

because glare is not a precisely defined lighting term, and 

measuring glare requires specialized equipment, this report instead 

focuses on providing sufficient illumination, selecting the best 

lighting design, and arranging the workspace to minimize glare. 

Regarding lighting design, most fluorescent ceiling light fixtures 

had louvers with a grid pattern containing 18 parabolic reflective 

cells. Some workstations near the atrium were positioned so 

that employees faced the courtyard atrium, an orientation that 

resulted in bright outdoor light behind the employee’s computer 

screen, producing a potential contrast problem, which might cause 

difficulty in reading characters and lettering on the screen. We 

also noted other potential sources of glare, such as placement of 

mirrors, in some workstations.

We learned that as the “cool white” fluorescent light bulbs in 

the ceiling fixtures burned out, the call center’s facility manager 

replaced them with “warm white” fluorescent bulbs, so we 

observed light fixtures containing bulbs of different colors. A cool 

white fluorescent bulb has a subtle blue color similar to ice. A 

warm white fluorescent light bulb imparts a more orange or red 

light on objects and is often described as a warmer light. 
Page 4 Health Hazard Evaluation Report 2012-0081-3169

Results

 (continued) Ventilation 

A variable air volume system provided heating and cooling to pod 

A. Constant volume air handling systems heated and cooled pods 

B, C, and D. The air handling systems we visually inspected were 

well maintained. According to the call center’s facility manager, 

the ventilation ducts had been cleaned about 2 weeks before our 

evaluation. All of the air handling systems used air filters with 

a minimum efficiency reporting value rating of 8 (similar to a 

minimum efficiency air filter), and these filters were changed 

quarterly. All air filters were last changed on April 6, 2012. 

The CO2 concentrations in the call center ranged from 410 to 

635 ppm during this evaluation; outdoor concentrations were 

380 ppm. We compare indoor and outdoor CO2 concentrations 

to determine if indoor occupied spaces are adequately ventilated 

[ANSI/ASHRAE 2010a]. Indoor CO2 concentrations that are 

similar to outdoor concentrations (as in this instance) suggest that 

the ventilation for the call center was adequate to dilute normal 

indoor contaminants and odors [ANSI/ASHRAE 2010a].

Temperature in the call center ranged from 68°F to 76°F, and 

relative humidity ranged from 43% to 49%, compared to an 

outdoor temperature of 60°F to 71°F and relative humidity ranging 

from 49% to 54%. These temperatures and relative humidity 

values are within the ASHRAE-recommended thermal comfort 

guidelines [ANSI/ASHRAE 2010b].

We measured airflow from 71 of 86 ceiling diffusers located in 

pods B, C, and D. The airflow results are listed in Appendix A, 

and Appendix B displays the ceiling diffuser locations. We were 

unable to measure airflow at 15 ceiling diffusers because they 

were blocked by furniture or file cabinets. Airflow from these 71 

diffusers ranged from 0 cfm at a diffuser in the union office in pod 

C to 917 cfm at a diffuser in the center of pod D. 

Employee Survey on Job Stress, Workrelated Health and Safety Concerns, and 

Psychosocial Factors at Work

We received 283 (85%) of the 333 surveys we handed out. Eightyone percent of respondents were female, and the average age was 
Health Hazard Evaluation Report 2012-0081-3169 Page 5

Results

 (continued) 44 years (range: 24–71 years). Respondents reported an average of 

12 years (range: 1–37) of employment with the call center.

Job Stress 

Participants were asked to rate their level of job stress over the past 

week on a scale from 0 (as low as it can be) to 10 (as high as it can 

be). The average job stress score was 6.3 (N = 279). Figure 1 shows 

the distribution of job stress scores.

Figure 1. Frequency of reported job stress level over the past week (N = 279).

Using an open-ended question, participants were also asked to 

identify one or more major source(s) of job stress, if any. Seventytwo (25%) respondents did not respond to this item. Job stressors 

reported by five or more employees are listed in Table 1.
Page 6 Health Hazard Evaluation Report 2012-0081-3169

Results

 (continued)

Table 1. Frequency of reported job stressors (N = 211)

Job Stressor Number of Participants 

Reporting (%)

Calls being timed and monitored by supervisor(s) 68 (32)

Interacting with hostile public 62 (29)

Issues with supervisors (e.g., feeling micromanaged, 

 lack of support or respect) 

56 (27)

Workload 30 (14)

Timekeeping (e.g., inadequate breaks, leave) 28 (13)

Time pressure during calls 25 (12)

Lighting in building (too bright) 18 (9)

Inconsistency or changes in procedures 12 (6)

Concern over quality of work 10 (5)

Favoritism 10 (5)

Lack of time to learn about technical/procedural changes 9 (4)

Low morale 9 (4)

Low perceived job control 9 (4)

Poor indoor air quality at work 6 (3) 

Technological issues with computer program(s) 6 (3)

Poor communication at work 5 (2)

Job ambiguity/lack of direction 5 (2)

Work-related Health Concerns

Participants were asked to rate their level of concern with workrelated health on a scale from 0 (as low as it can be) to 10 (as high 

as it can be). The average work-related health concern score was 6.8 

(N = 278). Figure 2 shows the distribution of work-related health 

concern scores.

Using an open-ended question, participants were also asked to 

explain their work-related health concern score. Eighty-three (29%) 

respondents did not respond to this item. Work-related health 

concerns reported by five or more employees are listed in Table 2.
Health Hazard Evaluation Report 2012-0081-3169 Page 7

Results

 (continued)

Figure 2. Frequency of reported work-related health concern scores (N = 278).

Table 2. Frequency of reported work-related health concerns (N = 200)

Work-related Health Concern Number of Participants 

Reporting (%)

Stress-related physical health concerns 73 (37) 

Indoor air quality 61 (29)

Germs from coworkers reporting to work while ill 33 (17)

Bright lighting 28 (14)

Mental health (e.g., anxiety, depression) 28 (14)

Cancer 26 (13)

Overly hot or cold indoor temperatures 23 (12)

Sedentary nature of the job 22 (12)

Vision problems with computer monitor 14 (7)

Repetitive motion injuries 14 (7)

Helicobacter pylori (H. pylori) 8 (4)

Secondhand smoke 7 (4)
Page 8 Health Hazard Evaluation Report 2012-0081-3169

Results

 (continued) Work-related Safety Concerns

Participants were asked to rate their level of concern for their 

personal safety at work on a scale from 0 (as low as it can be) to 10 

(as high as it can be). The average concern for personal safety at 

work score was 4.2 (N = 272). Figure 3 shows the distribution of 

concern for personal safety at work scores. 

Figure 3. Frequency of reported concern for personal safety at work scores (N = 272).

Using an open-ended question, participants were also asked 

to explain their concern for personal safety at work score. One 

hundred eighty (64%) respondents did not respond to this item. 

Concerns for personal safety at work reported by five or more 

employees are listed in Table 3.
Health Hazard Evaluation Report 2012-0081-3169 Page 9

Results

 (continued)

Table 3. Frequency of reported work-related safety concerns (N = 103)

Work-related Safety Concern

Number of 

Participants 

Reporting (%)

Being physically attacked in parking lot 52 (50)

Being physically attacked because of association with the U.S. 

government

23 (22)

Building security not paying attention 17 (17)

Being physically attacked by a coworker 10 (10)

Public entering building through open door 6 (6)

Being injured by poor drivers in parking lot 5 (5)

Being physically attacked by management 5 (5)

Safety drills/procedures perceived as inadequate 5 (5)

Poor communication when there is a potentially dangerous 

situation

 5 (5)

Psychosocial factors at work

Participants were asked to rate their level of agreement with 32 

psychosocial factors at work statements on a scale from 1 (strongly 

disagree) to 5 (strongly agree). Descriptive statistics for each of 

the 32 survey items are presented in Table 4. The 32 items can be 

grouped into the following six principal psychosocial factors: the 

physical work environment, job demands, job satisfaction, safety 

climate, perceived job control, and social support. 
Page 10 Health Hazard Evaluation Report 2012-0081-3169

Results

 (continued)

Table 4. Level of agreement (1 = Strongly Disagree; 5 = Strongly Agree) regarding work factors 

(N range: 277–283)

Survey Item Average Mode* Physical Work Environment

The level of noise in the area(s) in which I work is usually high 2.8 3.0

The level of lighting in the area(s) in which I work is usually too dim 1.4 1.0

The level of lighting in the area(s) in which I work is usually too bright 3.8 5.0

There is excessive glare on my computer screen due to lighting 3.4 5.0

The temperature of my work area(s) during the summer is usually 

comfortable 2.8 3.0

The temperature of my work area(s) during the winter is usually 

comfortable 2.7 3.0

The humidity in my work area(s) is usually either too high or too low 2.9 3.0

The level of air circulation in my work area(s) is good 2.3 1.0

The air in my work area(s) is clean and free of pollution 2.2 1.0

The overall quality of the physical environment where I work is poor 2.7 3.0

The work area(s) is/are overly crowded 2.1 1.0

Job

Demands

I am often required to work for long periods with my body in physically 

awkward positions 2.1 1.0

I have constant time pressure due to a heavy work load 3.0 5.0

I have many interruptions and disturbances while performing my job 2.4 1.0

Over time, my job has become more and more demanding 3.2 5.0

Job

Satisfaction

I receive the respect I deserve at work 3.2 5.0

My job promotion prospects are poor 3.0 3.0

I have experienced or I expect to experience an undesirable change in 

my work situation 2.4 1.0

My job security is poor 2.1 1.0

I am exposed to hostility or conflict from my supervisor(s) 2.1 1.0

Considering all my efforts and achievements, my salary/income is 

adequate 3.3 3.0

Safety

Climate

There is sufficient opportunity to discuss and deal with health & safety 

issues in meetings 2.5 1.0

There is open communication about health and safety issues within this 

workplace 2.7 1.0

Employees are regularly consulted about workplace health and safety 

issues 2.8 1.0

My supervisor is concerned about the welfare of those under him/her 3.5 5.0
Health Hazard Evaluation Report 2012-0081-3169 Page 11

Results

 (continued)

Table 4. Level of agreement (1 = Strongly Disagree; 5 = Strongly Agree) regarding work factors 

(N range: 277–283) (continued)

Survey Item Average Mode* Perceived Job Control

I am given a lot of freedom to decide how to do my own work 2.6 1.0

I am given a lot of freedom to decide the amount of work I do 2.1 1.0

I am given a lot of freedom to decide the pace of my work, that is, how 

fast or slow I work 2.4 1.0

I am allowed adequate breaks during my shift to stretch, rest my eyes, 

etc. 3.1 5.0

I get to do a variety of different tasks on my job 3.1 5.0

Social 

Support

The people I work with (my coworkers) are friendly 4.3 5.0

The people I work with (my coworkers) are helpful in getting the job done 4.0 5.0

* Mode: the most frequent response to the item.

Statistical Analyses

Composite scores were calculated for each of the six principal 

psychosocial factors by averaging the scores of the items within 

each factor. (Note: some survey items were reverse scored when 

necessary). Linear regression analyses were then used to determine 

which of the psychosocial factors at work are independently 

associated with job stress, work-related health concerns, and 

concern for personal safety at work scores.

Negative views of the physical work environment (P = 0.01) and job 

demands (P < 0.01) were associated with higher job stress scores. 

Positive views of job satisfaction (P < 0.05), perceived job control 

(P < 0.05), and social support (P < 0.05) were associated with lower 

job stress scores.

Negative views of the physical work environment (P < 0.01) and job 

demands (P < 0.01) were associated with greater work-related health 

concern scores.

Positive views of job satisfaction (P < 0.01) and safety climate 

(P < 0.05) were associated with lower concern for personal safety at 

work scores.
Page 12 Health Hazard Evaluation Report 2012-0081-3169

Results

 (continued) Other Workplace Observations and 

Employee Concerns 

During our walk-through evaluation we noted that a loading dock 

on the south side of the call center did not have a safety railing to 

prevent falls. Call center employees used the loading dock during 

their break periods.

The safety committee included only managers. According to the 

managers, the union had been invited to previous meetings but 

had not attended, and no employee representatives currently 

served on the committee. 

Survey responses indicated some concern about possible exposure 

to carcinogens at work. Several employees also mentioned that 

a sign posted on the door of a neighboring tenant warned of 

carcinogen exposures. The CDC website on occupational cancer 

clusters is a good resource for information that could be used to 

address these concerns. The address for this informative website 

can be found in the recommendations section of this report.

Regarding the carcinogen warning sign posted by a neighboring 

tenant, a 1986 California voter-approved initiative (Proposition 

65) required the state to publish a list of chemicals known to 

cause cancer, birth defects, or other reproductive harm. Under 

Proposition 65, businesses are required to give a “clear and 

reasonable” warning before knowingly exposing anyone to a listed 

chemical above a specified level [OEHHA 2012]. This warning can 

be included on product labels, published in a newspaper, or posted 

at the workplace or public area affected by the chemical [OEHHA 

2012]. Call center management should discuss the warning with 

the tenant to learn why it was provided so that an informed 

decision can be made about exposure to any of these chemicals.

Several survey participants expressed concern about contacting 

Helicobacter pylori (H. pylori) at work. H. pylori, a common bacterium 

found in the gastrointestinal tract, is associated with ulcers. 

Nearly two thirds of the world’s population is infected with H. 

pylori, though most people do not experience symptoms. It is very 

difficult to determine the cause of H. pylori infection, though the 

bacterium is believed to be transmitted from person to person 

primarily through oral-oral or fecal-oral contact. Because the 

source of H. pylori is not yet known, recommendations for avoiding 
Health Hazard Evaluation Report 2012-0081-3169 Page 13

Results

 (continued) infection have not been made. In general, it is wise to wash hands 

thoroughly, to eat food that has been properly prepared, and to 

drink water from a safe, clean source. A CDC resource for more 

information on H. pylori can be found in the recommendations 

section of this report.

We reviewed the office ergonomics training material that was 

provided to employees upon hire. This information was produced 

around 1999 and is outdated. OSHA has more up-to-date material 

available on its website at http://www.osha.gov/SLTC/etools/

computerworkstations/. The website contains a checklist that 

employees can use to tailor their adjustable workstations to create 

a safe and comfortable environment including monitor, chair, and 

workstation parameters.

Discussion Lighting Levels

The GSA lighting guidelines state that an average of 

50 footcandles should be maintained at working surfaces, 

30 footcandles in areas other than work surfaces, and 1 to 

10 footcandles (or the minimum necessary) to ensure safety 

in non-working areas [ANSI/IESNA 2004]. The American 

National Standard Institute recommends 30–100 footcandles 

for performance of visual tasks depending on contrast and 

text size [ANSI/IESNA 2004]. The OSHA eTools website for 

computer workstations recommends workstation lighting between 

20–73 footcandles depending on type of task and monitor 

used. Although the lighting levels we measured at the call center 

fall within all of these guidelines and meet the current lease 

requirements, we believe that a good lighting design should 

include both human perception and numerical standards. 

Therefore, the OSHA eTools and ANSI recommendations may 

provide a useful roadmap to designing a lighting policy for the 

call center that provides flexibility in the lighting levels at the 

workstations. For example, some employees may prefer light levels 

that may be at the lower end of the suggested lighting range, 

while others may prefer more lighting. Ultimately, the selection 

of lighting in a workspace should support the work, but the 

overall office lighting solution should consider user satisfaction to 

facilitate work performance [ANSI/IESNA 2004].
Page 14 Health Hazard Evaluation Report 2012-0081-3169

Discussion

 (continued) Although the lighting levels were within GSA recommendations, 

the design and location of the ceiling lighting fixtures could still 

produce high luminance levels in the employees’ field of view, 

potentially causing some of the employees glare discomfort. 

Selecting the most appropriate parabolic lighting louver for the 

call center ceiling light fixtures should help control the light into 

a designated area and also provide a low brightness appearance, 

thereby reducing glare. The ability to control the direction of 

light and its apparent brightness results from the size and shape 

of the vertical cell walls in a parabolic louver. At the time of our 

evaluation we observed that most of the ceiling light fixtures 

used parabolic louvers with 18 cells (each cell approximately 7.5′′

square). Switching to a parabolic louver with smaller cells (for 

example, 0.5′′ square cells) may be preferable in office situations 

such as the call center where computer usage dictates maximum 

glare control. Parabolic louvers with smaller cells are better able 

to direct all light into a task area and minimize or eliminate 

objectionable sources of brightness or glare [Lumco 2012]. 

Another work practice at the call center that may have resulted 

in visual discomfort was computer use. During our walk-through 

survey we observed that call center employees used different 

computer programs and databases in responding to a customer’s 

question or problem. As a result, employees switched back and 

forth between white and dark background displays, depending 

on the software used. Because the luminance level of a white 

background display on a computer is more similar to the work 

environment than a dark background display, it is usually more 

comfortable. Dark background displays also require lower light 

levels in offices to achieve the correct luminance ratio [CVC 2012]. 

Ventilation

Our ventilation measurements demonstrated that supply air was 

not evenly distributed to all areas of the call center. However, 

the CO2

 concentrations during our evaluation were comparable 

to outdoor concentrations, suggesting that an adequate amount 

of outdoor air was being provided to dilute nuisance odors and 

maintain effective ventilation [ANSI/ASHRAE 2010a]. Although 

temperature and relative humidity measurements were within the 

ASHRAE-recommended thermal comfort guidelines during our 

evaluation, imbalanced air handling systems may not provide the 
Health Hazard Evaluation Report 2012-0081-3169 Page 15

Discussion

 (continued) maximum occupant comfort at the lowest energy cost [ANSI/

ASHRAE 2010b]. We asked for, but were not provided with, a test 

and balance report from the building owner, so we are unable to 

compare our airflow measurements to the design airflow rates. 

Employee Survey

The level of self-reported job stress was moderately high at this 

workplace, with 61% of participants rating their job stress level as 

6 or greater on a scale from 0 to 10, with 10 representing extreme 

stress (average = 6.3). The results of our survey suggest that job 

stress is associated with various factors, including the nature of the 

job (e.g., high call volume, time pressure, having calls monitored, 

interacting with a hostile public), psychosocial factors (e.g., 

negative perceptions of management/supervision, perceived lack 

of communication), and concerns regarding the physical working 

environment (e.g., lighting, poor air quality and circulation). 

NIOSH has completed several HHEs at call centers in the past, 

and found that many employees experience a high workload, face 

hostility or abuse from customers, and report being physically 

and mentally exhausted at the end of their workday [NIOSH 

1994, 2007a,b]. These job stressors have consistently been found 

to recur in the call centers we have evaluated. What makes the 

present HHE unique is that the request involved concerns over 

the physical work environment and its impact on job stress and 

health. The survey results showed that concerns about the physical 

work environment were positively associated with job stress and 

work-related health concerns. Specifically, participants were most 

concerned about lighting being too bright, excessive glare on their 

computer monitors, and indoor environmental quality problems, 

such as proper air circulation and general air quality. Addressing 

these issues in the working environment may reduce employees’ 

job stress and work-related health concerns. 

Research has shown that job resources such as social support from 

management and coworkers, feedback, and employee involvement 

in decision making and providing input to management is 

associated with greater job satisfaction, positive perceptions of 

work, and lower turnover [Kain and Jex 2010]. A relative strength 

highlighted by the survey results is that many of the participants 

find their coworkers to be friendly and helpful. Favorable (higher) 

scores in this factor of social support were associated with lower 

job stress scores.
Page 16 Health Hazard Evaluation Report 2012-0081-3169

Discussion

 (continued) While most participants reported a positive relationship with 

their supervisor(s), 25% (N = 70) of participants either disagreed 

or strongly disagreed that their supervisor was concerned 

about the welfare of those under him/her. This may be linked 

to responses to the safety climate factor of the survey, which 

indicates that participants were not satisfied with communication 

between managers and employees regarding health and safety 

issues at the workplace. Forming a joint management, union, and 

employee safety committee, as well as developing a formal process 

for employees to report safety and health concerns and receive 

feedback may strengthen perceptions of support and concern 

from management.

Conclusions

Recommendations

Our lighting measurements show that lease requirements were 

being met, but employee perception and satisfaction were not 

being considered with the current lighting design. Our ventilation 

measurements showed that supply air was not evenly distributed 

to all areas of the call center. Addressing specific job stressors 

identified in the employee survey may reduce the moderately high 

levels of job stress and work-related health concerns.

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

below to create a more healthful workplace. We encourage the call 

center 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 call center. 

1. Reinstate the policy that employees may have less lighting 

in their workspace (if supported by a doctor’s note) by 

deactivating or removing fluorescent bulbs.

2. Consider a trial process for different lighting configurations 

in different pods. This could include removal of bulbs or 

changing lighting louvers to better control illumination to 

designated areas. Solicit employee feedback during the process.

3. Consider accelerating the replacement of the fluorescent 

bulbs to avoid having both “cool white” and “warm white” 

bulbs in the same light fixture.
Health Hazard Evaluation Report 2012-0081-3169 Page 17

Recommendations

 (continued) 4. Minimize reflective surfaces at employees’ workstations to reduce 

glare. Employees could also slightly tilt their monitor downward, 

being mindful to maintain proper workstation settings.

5. Remind all employees of proper workstation settings, 

particularly computer monitor height. The top of the 

computer monitor should be flush with the operator’s brow 

to prevent neck strain.

6. Have a ventilation engineer evaluate the ventilation systems 

and areas of uneven airflow in pods B, C and D, then 

conduct a test and balance on these air handling systems. 

7. Clean the exterior of the supply and return air vents in the 

workplace regularly.

8. Start a joint management, union, and employee health and 

safety committee.

9. Create a formal procedure for employees to report and 

receive feedback regarding health and safety concerns, 

perhaps through the health and safety committee. This 

would involve documenting the concerns, explaining what 

will be done to address the concerns, or explaining why no 

action is necessary. The documentation of this process can 

then be shared with all employees as part of the committee 

meeting minutes or by e-mail.

10. Give employees feedback that they can use to improve their 

communications with customers. Do not forget to provide 

positive feedback to employees on what they did well.

11. Ask employees to comment on processes and procedures 

being used in the call center. Listen to their suggestions on 

how things can be improved. This can improve employee 

morale and productivity.

12. Encourage employees who interact with a hostile customer 

on the phone to immediately debrief with their supervisor or 

another coworker following the call. This practice may boost 

social support and have a buffering effect on job stress. 

13.Evaluate employee workload and obtain employee input 

regarding the volume of calls they receive daily and how it 

affects job stress, job satisfaction, and job control. Engage 

employees in discussion about whether workload could be 

better managed and how.
Page 18 Health Hazard Evaluation Report 2012-0081-3169

Recommendations 

(continued) 14. Employees experiencing symptoms of anxiety, depression, 

anger, or any other mental health problems should 

seek counseling from a licensed clinical psychologist or 

psychiatrist if such symptoms are interfering with social, 

occupational, or other important areas of functioning.

15.Provide all employees with training in workplace violence, 

workplace bullying, and stress reduction. 

16. Encourage employees to immediately report any concerns 

regarding suspicious behavior or threatening language/

statements made by coworkers or immediate supervisors. If 

one’s immediate supervisor is the individual in question, 

the report should be made to his/her supervisor.

17. All employees and supervisors should be familiar with the 

building’s evacuation plan and know how to quickly and 

safely exit the building in the case of an emergency. 

18.If practical, consider arranging for security to escort call 

center employees who do not feel safe walking to/from their 

vehicle in the parking lot.

19.Verify if a sign warning of carcinogen exposure is located 

on the door of the neighboring tenant. If so, obtain 

information as to why this is so, and share this information 

with employees.

20.Inform employees concerned about occupational cancer that 

they can find information on cancer clusters from CDC at 

http://www.cdc.gov/niosh/topics/cancer/clusters.html.

21. Inform employees concerned about H. pylori that they can 

find additional information from CDC at http://www.cdc.

gov/ulcer/files/hpfacts.PDF. Individuals who are concerned 

that they are experiencing symptoms of the infection should 

speak to their primary care physician.

22.Discourage employees from reporting to work when they are 

ill if they are likely contagious. 

23.Install a protective railing on the loading dock to prevent falls.
Health Hazard Evaluation Report 2012-0081-3169 Page 19

References

ANSI/ASHRAE [2010a]. Ventilation for acceptable indoor 

air quality. American National Standards Institute/ASHRAE 

standard 62.1-2010. Atlanta, GA: American Society of Heating, 

Refrigerating, and Air-Conditioning Engineers, Inc.

ANSI/ASHRAE [2010b]. Thermal environmental conditions 

for human occupancy. American National Standards Institute/

ASHRAE standard 55-2010. Atlanta, GA: American Society for 

Heating, Refrigerating, and Air-Conditioning Engineers, Inc.

ANSI/IESNA [2004]. IESNA Office Lighting Committee. 

American national standard practice for office lighting. RP-1-04.

CVC [2012]. Suggestions for improving comfort at a computer 

workstation. Online article from Corporate Vision Consulting. 

[http://www.cvconsulting.com/articles4.shtml]. Date accessed: 

December 2012. 

Crouch CL [1978]. Lighting for seeing. In: Clayton GD, Clayton 

FE, eds. Patty’s industrial hygiene and toxicology, 3rd rev. ed. Vol. 

1. New York: Wiley-Interscience Publishers, pp. 513–515. 

Kain J, Jex S [2010]. Karasek’s (1979) job demands-control 

model: a summary of current issues and recommendations for 

future research. In: Perrewe PL, Ganster DC, eds. Research in 

occupational stress and well-being. Vol. 8: New developments in 

theoretical and conceptual approaches to job stress. Bingley, UK: 

Emerald Books, pp. 237–268. 

Lumco [2012]. Optics – optiques guide. Online article from 

StandardTM. [http://www.lumco.ca/eclairage/doc/opt_guide.pdf]. 

Date accessed: December 2012.

NIOSH [1994]. Hazard evaluation and technical assistance report: 

Social Security Administration teleservice centers – Boston, 

Massachusetts, Fort Lauderdale, Florida. 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 Report No. 92-0382-2450.

NIOSH [2007a]. Hazard evaluation and technical assistance report: 

Cincinnati police department police communication section – 

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

and Human Services, Centers for Disease Control and Prevention, 
Page 20 Health Hazard Evaluation Report 2012-0081-3169

References

(continued) National Institute for Occupational Safety and Health, NIOSH 

HETA Report No. 1999-0199-3053.

NIOSH [2007b]. Hazard evaluation and technical assistance 

report: New York City police department, police communications 

section – New York, New York. 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 Report No. 97-0137-3026.

OEHHA [2012]. Proposition 65 fact sheet for tenants. California 

Office of Environmental Health Hazard Assessment. [http://www.

oehha.ca.gov/prop65/background/P65ten.html]. Date accessed: 

December 2012.
Health Hazard Evaluation Report 2012-0081-3169 Page 21

Appendix A: Tables

Table A1. Airflow measurements in call center pod B

Diffuser Location

(Figure B1)

Airflow (cfm)

Measurement Comments

Average 1 2 3

B1* — — — — Blocked by furniture

B2 — — — — Blocked by furniture

B3 — — — — Blocked by furniture

B4 — — — — Blocked by furniture

B5 450 420 410 427

B6 475 480 490 482

B7 250 250 255 252

B8 340 320 345 335

B9 350 340 345 345

B10 385 385 380 383

B11 355 370 360 362

B12 340 330 340 337

B13 290 285 300 292

B14 580 580 600 587

B15 — — — — Blocked by furniture

B16 240 230 235 235

B17 310 290 285 295

B18 225 220 230 225

B19 — — — — Blocked by furniture

B20 — — — — Blocked by furniture

B21 — — — — Blocked by furniture

B22 440 450 445 445

B23 620 610 610 613

B24 450 460 465 458

B25 512 539 522 524

B26 249 257 266 257

B27 276 295 279 283

B28 364 340 328 344

B29 — — — — Blocked by furniture

B30 553 546 551 550

B31 199 173 187 186

B32 288 292 288 289

B33 541 527 539 536

B34 185 203 168 185 Individual office

* All ceiling diffusers were 2′ x 2′, unless otherwise noted.
Page 22 Health Hazard Evaluation Report 2012-0081-3169

Appendix A: Tables

 (continued)

Table A2. Airflow measurements in call center pod C

Diffuser Location

(Figure B2)

Airflow (cfm)

Measurement Comments

Average 1 2 3

C1* 172 176 173 174

C2 553 611 540 568 Noise from air blowing from diffuser

C3 392 421 353 389

C4 414 415 421 417

C5 472 461 450 461

C6 520 583 531 545

C7 387 374 367 376

C8 146 148 148 147

C9 136 128 99 121

C10 0 0 0 0 No air movement from diffuser

C11 100 106 101 102 1′ X 1′ diffuser

C12 36 111 36 61 1′ X 1′ diffuser

C13 557 523 540 540

C14 387 396 392 392

C15 353 356 358 356

C16 257 242 252 250

C17 236 239 232 236

C18 649 674 666 663 Noise from air blowing from diffuser

C19 265 248 287 267

C20 492 503 457 484

C21 282 296 283 287

C22 208 231 221 220

C23 — — — — Blocked by furniture

C24 — — — — Blocked by furniture

C25 269 295 284 283

C26 264 309 300 291

C27 448 459 459 455

* All ceiling diffusers were 2′ x 2′, unless otherwise noted.
Health Hazard Evaluation Report 2012-0081-3169 Page 23

Appendix A: Tables

 (continued)

Table A3. Airflow measurements in call center pod D

Diffuser Location

(Figure B3)

Airflow (cfm)

Measurement Comments

Average 1 2 3

D1 428 416 407 417

D2 274 245 261 260

D3 81 77 83 80

D4 496 489 527 504

D5 333 330 310 324

D6 85 79 87 84

D7 388 414 412 405

D8 585 574 635 598

D9 409 378 474 420

D10 407 350 420 392

D11 947 852 951 917 Noise from air blowing from diffuser

D12 248 227 263 246

D13 504 509 517 510

D14 — — — — Blocked by furniture

D15 272 256 264 264

D16 328 345 315 329

D17 — — — — Blocked by furniture

D18 401 396 380 392

D19 167 176 153 165 Individual office

D20 323 352 333 336 Noisy; different diffuser design

D21 — — — — Blocked by furniture

D22 — — — — Blocked by furniture

D23 537 504 481 507

D24 499 491 454 481

D25 386 375 386 382 Diffuser partially blocked by window shade

* All ceiling diffusers were 2′ x 2′, unless otherwise noted.
Page 24 Health Hazard Evaluation Report 2012-0081-3169

Appendix B: Figures 
Health Hazard Evaluation Report 2012-0081-3169 Page 25

Appendix B: Figures

 (Continued) 
Page 26 Health Hazard Evaluation Report 2012-0081-3169

Appendix B: Figures

 (Continued) 
Health Hazard Evaluation Report 2012-0081-3169 Page 27

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 Douglas Wiegand, Jessica Ramsey, 

Gregory Burr, and JungHo Choi of HETAB, Division of 

Surveillance, Hazard Evaluations and Field Studies. Industrial 

hygiene equipment and logistical support was provided by Donald 

Booher and Karl Feldmann. Statistical consultation was provided 

by Charles Mueller. Health communication assistance was provided 

by Stefanie Brown. Editorial assistance was provided by Ellen 

Galloway. Desktop publishing was performed by Mary Winfree.

Copies of this report have been sent to employee and management 

representatives at the call center, 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 [2013]. Health hazard evaluation report: lighting, indoor environmental 

quality concerns, and job stress at a call center – California. By Wiegand D, 

Ramsey J, Burr G, Choi J. 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. 2012-0081-3169.

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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