NIOSH HEALTH HAZARD EVALUATION REPORT 

HETA #2003-0273; 2003-0280; 2003-0287-2974 

Kaiser-Permanente 

Santa Teresa, Redwood City, and 

Santa Clara, California 

June 2005 

DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Institute for Occupational Safety and Health
ii 

PREFACE

The Hazard Evaluation 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 (OSHA) 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 employers 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 Randy L. Tubbs of HETAB, Division of Surveillance, Hazard Evaluations 

and Field Studies (DSHEFS) and Chucri A. Kardous of the Engineering and Physical Hazards Branch, 

Division of Applied Research and Technology (DART). Laboratory support was provided by 

Pamela Graydon of the Hearing Loss Prevention Team, DART. Desktop publishing was performed by 

Shawna Watts. Editorial assistance was provided by Ellen Galloway. 

Copies of this report have been sent to employee and management representatives at Kaiser-Permanente, 

the Cal-OSHA Department of Industrial Relations Office, the OSHA Salt Lake Technical Center, and the 

OSHA Regional Office. This report is not copyrighted and may be freely reproduced. The report may be 

viewed and printed from the following internet address: http://www.cdc.gov/niosh/hhe. 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

Evaluation of a Telephone Dictation System (C-Phone) used by Medical 

Transcriptionists for Excessive Noise Exposures Through Their Headsets

The local union representing medical transcriptionists at Kaiser-Permanente Hospitals’ Health Information 

Management (HIM) department submitted a health hazard evaluation request because of concerns about 

excessive noise exposures. The noise levels delivered through headsets transcriptionists wear while recording 

medical records onto computer files were evaluated through a site visit to the facilities and an extensive 

laboratory study. 

What NIOSH Did

 We measured the background noise in the 

offices where the transcriptionists work. 

 We interviewed employees about the amount 

of time they have been transcriptionists and 

what they felt about the C-phone dictation 

system. We also asked if they had any 

symptoms they felt were the result of their 

work conditions. 

 We tested a C-phone dictation system in the 

NIOSH laboratory to determine the noise 

levels delivered through the headsets. 

What NIOSH Found

 Noise levels can be excessive when the 

volume control on the C-phone is left in the 

maximum position. 

 The C-phone limits the noise levels to 110 dB 

SPL at the workers’ ears. 

 Of the interviewed transcriptionists, 62% had 

problems with the C-phone (for example, 

voice prompts too loud, varying noise levels, 

little control over volume levels), and 28% of 

them reported symptoms they felt were related 

to their work. 

 Work with the manufacturer of the C-phone to 

further reduce the noise levels and improve the 

clarity of the dictation. 

 Train physicians about effective ways to 

improve the quality of the dictated records. 

 Offer yearly hearing tests to the medical 

transcriptionists. 

What Kaiser Permanente Employees 

Can Do 

 Do not set the volume control above the 

middle point on the C-phone whenever 

possible. 

 Continue to participate in the headset 

committee and voice your concerns to the 

HIM department managers. 

What Kaiser Permanente Managers 

Can Do

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 

#2003-0273; 2003-0280; 2003-0287-2974
iv 

Health Hazard Evaluation Report 2003-0273; 

2003-0280; 2003-0287-2974 

Kaiser-Permanente 

Santa Teresa, Redwood City, and 

Santa Clara, California 

June 2005 

Randy L. Tubbs, Ph.D. 

Chucri A. Kardous, P.E. 

SUMMARY

In May and June 2003, the National Institute for Occupational Safety and Health (NIOSH) received three 

separate requests from the Service Employees International Union (SEIU) Local 250 officials to conduct 

health hazard evaluations in the Health Information Management (HIM) offices of Kaiser Permanente 

hospitals in the South Bay region of California. The requests involved medical transcriptionists who use a 

telephone dictation system to transcribe medical records dictated by hospital physicians. The 

transcriptionists were concerned about excessive noise from the telephone headset. Before NIOSH 

received the union’s request, a California Occupational Safety and Health Administration (Cal-OSHA) 

industrial hygienist began an investigation at Kaiser Permanente in April 2003. Shortly thereafter, CalOSHA contacted the Federal OSHA Salt Lake Technical Center about a procedure for measuring headset 

noise they had published in the OSHA Technical Manual. Cal-OSHA also contacted NIOSH to discuss 

the technical difficulties associated with the investigation. These discussions eventually led to the request 

from the union on behalf of the employees. 

During the week of January 27, 2004, NIOSH and OSHA investigators visited the Kaiser Permanente 

hospitals and measured the noise levels through the transcriptionists’ headsets with an acoustic 

mannequin and the ambient noise levels in their offices. Employees in each of the three HIM departments 

were interviewed by a NIOSH investigator to document their concerns about the dictation system and any 

symptoms they felt were the result of their work. In the fall of 2004, a telephone dictation system similar 

to the ones used at Kaiser Permanente was evaluated in the NIOSH Acoustics Laboratory in Cincinnati, 

Ohio, using actual medical dictations. These dictations were chosen by the transcriptionists as 

problematic. The noise levels and quality of the recordings were evaluated at three volume settings to 

determine the risk for excess noise exposure and the clarity of the dictations. 

The NIOSH investigators determined that a potential for excessive noise exposure exists 

with the dictation equipment used by the medical transcriptionists at Kaiser Permanente. 

Excessive noise is delivered through the headsets when the manual volume control on the 

telephone dictation system is left in the maximum position. If the volume control is 

placed in the middle position or lower, the noise exposures through the headsets are at a 

safe level for an 8-hour work shift. Recommendations are offered to the employees and 

management at Kaiser Permanente to maintain the noise levels from the headsets at a safe 

level and to improve the clarity of medical dictations. 

Keywords: NAICS Code 622110 (General medical and surgical hospitals), medical transcriptionists, 

medical records, dictation, hearing loss, noise, telephone headsets, room noise, hearing conservation 

program 
Table of Contents 

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

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

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

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

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

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

Field Survey.............................................................................................................................................2

Area noise analysis..............................................................................................................................2

Employee interviews ...........................................................................................................................2

Laboratory Analysis ...............................................................................................................................3

Equipment description .......................................................................................................................3

Measurement and analysis .................................................................................................................3

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

Noise .........................................................................................................................................................4

Results ..........................................................................................................................................................5

Field Survey.............................................................................................................................................5

Area noise analysis..............................................................................................................................5

Employee interviews ...........................................................................................................................5

Laboratory Analysis ...............................................................................................................................6

Discussion ....................................................................................................................................................6

Conclusions..................................................................................................................................................8

Recommendations.......................................................................................................................................8

References....................................................................................................................................................9
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 1 

INTRODUCTION

In May and June 2003, the National Institute for 

Occupational Safety and Health (NIOSH) 

received requests from the Service Employees 

International Union (SEIU) Local 250 to 

conduct health hazard evaluations (HHEs) at 

three Kaiser Permanente hospitals in the South 

Bay region of California. The request involved 

the medical transcriptionists at hospitals in Santa 

Teresa, Santa Clara, and Redwood City. The 

employees at these three locations had concerns 

about the dictation telephones, referred to as Cphones, they used to transcribe medical records 

dictated by physicians, and the amount of noise 

generated through the system’s headsets. Before 

NIOSH received the union’s request, a 

California Occupational Safety and Health 

Administration (Cal-OSHA) industrial hygienist 

began an investigation at Kaiser Permanente in 

April 2003. Shortly thereafter, Cal-OSHA 

contacted the Federal OSHA Salt Lake 

Technical Center about a procedure for 

measuring headset noise they had published in 

the OSHA Technical Manual. Cal-OSHA also 

contacted NIOSH to discuss the technical 

difficulties associated with the investigation. 

These discussions eventually led to the request 

from the union on behalf of the employees. 

On January 26, 2004, a meeting was held in 

Santa Teresa, California, with representatives 

from the three Kaiser Permanente hospitals, 

SEIU Local 250, Cal-OSHA, the Federal 

Occupational Safety and Health Administration 

(OSHA) Salt Lake Technical Center, and 

NIOSH to discuss the workers’ concerns and the 

steps the hospital had taken to reduce loud noise 

transmission through the headsets. These 

representatives also discussed the protocol the 

OSHA and NIOSH investigators planned to use 

to document noise levels employees received 

during the work day with the transcription 

system and the room conditions where the 

transcriptionists worked. 

On January 27-28, 2004, NIOSH and OSHA 

investigators measured noise levels directly from 

a dictation telephone system through the 

headsets, measured area sound levels of the 

office space where employees worked, and 

interviewed employees about their likes and 

dislikes about the system in the Santa Teresa 

location. On January 29, 2004, the NIOSH and 

OSHA investigators made the same 

measurements and interviewed transcriptionists 

at the Santa Clara location. On January 30, 2004, 

the NIOSH investigator traveled to the Redwood 

City facility to interview the transcriptionists 

and measure the room noise where they worked. 

In April 2004, NIOSH purchased the same 

dictation telephone system with three headsets 

from the same manufacturer as those used by 

Kaiser Permanente to conduct further testing in 

the NIOSH Cincinnati Acoustics Laboratory. 

Arrangements were made with the medical 

transcription department to have actual 

physician dictations from all three locations 

available beginning in September 2004, to play 

through the NIOSH transcription system for 

detailed analyses of these signals. 

A report of the work conducted by the OSHA 

Salt Lake Technical Center was issued to all 

parties in March 2004. Cal-OSHA issued 

Information Memoranda to Kaiser Permanente 

Santa Teresa and Santa Clara on March 5, 2004. 

These documents are included in this report as 

Appendix A and B. 

BACKGROUND

Kaiser Permanente employs 270 medical 

transcriptionists in Northern California, which 

includes the facilities at Santa Teresa, Santa 

Clara, and Redwood City. Approximately 30 

people are employed at these three locations. 

The transcriptionists work in an open-office 

setting, with a computer workstation and the Cphone at their desk. At Santa Teresa and 

Redwood City, the Health Information 

Management (HIM) departments are in their 

own rooms. At Santa Clara, the transcriptionists 

share office space with other departments 

(Figures 1-3). 

Transcriptionists listen to the medical record 

through their headsets and type the record into a 

computer. The transcriptionist continually 

reverses and forwards the dictation record to 
Page 2 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

insure that the correct information is being 

transcribed into the patient’s record. In May 

2002, a new dictation/transcription system was 

purchased from the Dictaphone Corporation for 

use in the HIM departments at the Santa Teresa, 

Santa Clara, and Redwood City facilities. 

Shortly after the system’s full implementation, 

transcriptionists reported that fluctuations in the 

sound intensity of the dictation records occurred 

without any apparent reason. They reported that 

the voice level of a physician dictating a medical 

record would suddenly drop in intensity, which 

required the transcriptionist to move the volume 

bar to a higher output to understand what was 

being said. After a short period of time, the 

volume would suddenly increase without 

warning, delivering a very loud sound level 

through the headset. They also reported that the 

recorded voice prompts at the beginning and end 

of the report were at a high intensity level on 

which the volume bar had no effect. The system 

additionally played high pitched, beeping sounds 

that were triggered whenever the foot pedal was 

pressed or when the keypad of the C-phone was 

used. The transcriptionists reported that the 

headsets did nothing to block environmental 

noises in their workspace, including people 

talking in the HIM department and in adjacent 

offices; music played by fellow employees; and 

heating, ventilating, and air conditioning 

(HVAC) air noise from the supply vents. After 

the C-phone had been in place for several 

months, some transcriptionists complained of 

tinnitus and subsequently had audiometric 

testing performed. Four employees were 

reported to have some degree of hearing loss, 

ranging from mild to a 40% loss. 

In November 2003, the office of EH&S at 

Kaiser Permanente administered a survey 

questionnaire to employees at the Medical 

Centers in northern California where the 

Dictaphone Corp. equipment was used, which 

included the HIM departments at Santa Teresa, 

Santa Clara, and Redwood City. A total of 21 

surveys were returned by the employees at these 

three locations. All but one of the respondents 

used the C-phone dictation/transcription system. 

Sixteen of the transcriptionists reported 

problems with the C-phone, with loudness and 

volume fluctuations as the most common 

complaints. Kaiser Permanente attempted to 

alter the C-phone by retroactively installing 

electronic resistors in the system to reduce the 

volume of the signals, but employees reported 

that this met with limited success. 

METHODS

Field Survey 

Area noise analysis 

The spectral area noise measurements were 

made with a Larson-Davis Laboratory Model 

2800 Real-Time Analyzer and a Larson-Davis 

Laboratory Model 2559 1⁄2" random incidence 

response microphone. The analyzer allows for 

the analysis of noise into its spectral components 

in a real-time mode. The 1⁄2"-diameter 

microphone has a frequency response range 

(± 2 decibels [dB]) from 4 Hertz (Hz) to 

21 kilohertz (kHz) that allows for the analysis of 

sounds in the region of concern. One-third 

octave bands consisting of center frequencies 

from 25 Hz to 20 kHz were integrated for 30 

seconds and stored in the analyzer for later 

analysis. The analyzer also calculates the overall 

A-weighted value (dBA) and the overall 

unweighted value as a sound pressure level 

(dB SPL). 

The sound levels in the room where the 

transcriptionists worked were captured at each 

workstation in the three hospital locations, 

regardless of whether the workstation was 

occupied at the time of the survey. The analyzer 

was located near the position where the 

employee would be seated and the microphone 

placed where the transcriptionist’s ears would be 

located. 

Employee interviews 

All transcriptionists at work on the days of the 

survey along with the HIM department 

managers were interviewed in private by the 

NIOSH investigator. Each employee was asked 

about the number of years worked in medical 

transcription at Kaiser Permanente and in the 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 3 

profession. They were also queried about their 

opinions on the C-phone system currently in use; 

the physical characteristics of their work space, 

e.g., temperature, background noise, office 

ergonomics; whether they had been given a 

hearing test through work and any changes in 

their hearing ability; and any other concerns or 

complaints about health and safety issues at their 

workplace. 

Laboratory Analysis 

The assessment consisted of (1) evaluating noise 

exposures from transcribed recordings identified 

to be problematic by Kaiser Permanente 

employees, (2) evaluating the quality and 

performance of the Dictaphone C-Phone system, 

and (3) evaluating the three headsets commonly 

used by Kaiser Permanente transcriptionists. 

Equipment description 

NIOSH purchased a Dictaphone C-phone and 

associated equipment and accessories for testing 

at the Cincinnati NIOSH Acoustics Laboratory. 

NIOSH was provided access to three sets of 

dictation recordings identified by employees as 

problematic from the Santa Clara, Santa Teresa, 

and Redwood City HIM departments (a total of 

20 dictations). Recordings were handled as 

confidential medical information while in 

NIOSH possession. The recordings were 

temporarily downloaded and stored onto a 

TASCAM DA-P1 digital audio tape (DAT) 

recorder sampling at 48,000 samples per second 

(48 kHz). A test signal, the phone line dial-tone, 

the dictation message header, and the noise 

emitted by activation of the foot-pedal were also 

recorded. The recordings were played back into 

the Knowles Electronic Mannequin for Acoustic 

Research (KEMAR) with standard adult-size 

artificial external ears and half-inch 

Bruel&Kjaer (B&K) microphones Type 4165. 

The microphones were powered by a B&K 2807 

power supply and the outputs analyzed with a 

Stanford Research Systems Model SR785 signal 

analyzer. KEMAR’s microphones were 

calibrated using B&K 4230 acoustic calibrator 

that produces a 94 dB SPL tone at 1000 Hz. The 

calibration tone was used to evaluate and 

compare the various sound levels of the 

recordings. The recordings were transferred to a 

personal computer for later analysis using an 

Audiophile M-Audio sound card and GoldWave 

v5.08 audio editor. The test setup is shown in 

Figures 4 and 5. 

Measurement and analysis 

The recordings were analyzed using the NIOSH 

noise measurement software (NNMS) that 

measured average and peak levels of each 

recording as well as analyzing the frequency 

spectrum and octave and one-third octave band 

spectra. In addition to evaluating the quality and 

sound levels produced by the recordings, the 

overall performance of the three headsets used 

with the C-phone, namely, the Deluxe headset, 

the Light headset, and the Sound Band headset 

were also tested using the sound source feature 

on the SR785 signal analyzer to produce a swept 

sine signal from 100 Hz to 20 KHz with 

increasing levels of outputs from 10 millivolt 

(mV) to 5 volt (V). 

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 
Page 4 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

criteria. Also, some substances are absorbed by 

direct contact with the skin and mucous 

membranes, and thus potentially increases 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),1

 (2) the American Conference of 

Governmental Industrial Hygienists’ (ACGIH®) 

Threshold Limit Values (TLVs®),2

 and (3) the 

U.S. Department of Labor, Occupational Safety 

and Health Administration (OSHA) Permissible 

Exposure Limits (PELs).3

 Employers are 

encouraged to follow the OSHA limits, the 

NIOSH RELs, the ACGIH TLVs, or whichever 

are the more protective criteria. 

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. 

Noise 

Noise-induced loss of hearing is an irreversible, 

sensorineural condition that progresses with 

exposure. Although hearing ability declines with 

age (presbycusis) in all populations, exposure to 

noise produces hearing loss greater than that 

resulting from the natural aging process. This 

noise-induced loss is caused by damage to nerve 

cells of the inner ear (cochlea) and, unlike some 

conductive hearing disorders, cannot be treated 

medically.4

 While loss of hearing may result 

from a single exposure to a very brief impulse 

noise or explosion, such traumatic losses are 

rare. In most cases, noise-induced hearing loss is 

insidious. Typically, it begins to develop at 4000 

or 6000 Hz (the hearing range is 20 Hz to 20000 

Hz) and spreads to lower and higher frequencies. 

Often, material impairment has occurred before 

the condition is clearly recognized. Such 

impairment is usually severe enough to 

permanently affect a person's ability to hear and 

understand speech under everyday conditions. 

Although the primary frequencies of human 

speech range from 200 Hz to 2000 Hz, research 

has shown that the consonant sounds, which 

enable people to distinguish words such as "fish" 

from "fist," have still higher frequency 

components.5

The A-weighted decibel is the preferred unit for 

measuring sound levels to assess worker noise 

exposures. The dBA scale is weighted to 

approximate the sensory response of the human 

ear to sound frequencies near the threshold of 

hearing. The decibel unit is dimensionless, and 

represents the logarithmic relationship of the 

measured sound pressure level to an arbitrary 

reference sound pressure (20 micropascals, the 

normal threshold of human hearing at a 

frequency of 1000 Hz). Decibel units are used 

because of the very large range of sound 

pressure levels which are audible to the human 

ear. Because the dBA scale is logarithmic, 

increases of 3 dBA, 10 dBA, and 20 dBA 

represent a doubling, tenfold increase, and 

hundredfold increase of sound energy, 

respectively. It should be noted that noise 

exposures expressed in decibels cannot be 

averaged by taking the simple arithmetic mean. 

The OSHA standard for occupational exposure 

to noise (29 CFR 1910.95)6

 specifies a 

maximum PEL of 90 dBA for a duration of 8 

hours per day. The regulation, in calculating the 

PEL, uses a 5 dB time/intensity trading 

relationship, or exchange rate. This means that a 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 5 

person may be exposed to noise levels of 95 

dBA for no more than 4 hours, to 100 dBA for 2 

hours, etc. Conversely, up to 16 hours exposure 

to 85 dBA is allowed by this exchange rate. 

NIOSH, in its Criteria for a Recommended 

Standard,7

 and the ACGIH,2 propose exposure 

criteria of 85 dBA as a TWA for 8 hours, 5 dB 

less than the OSHA standard. The criteria also 

use a more conservative 3 dB time/intensity 

trading relationship in calculating exposure 

limits. Thus, a worker can be exposed to 85 dBA 

for 8 hours, but to no more than 88 dBA for 4 

hours or 91 dBA for 2 hours. Twelve-hour 

exposures have to be 83 dBA or less according 

to the NIOSH REL. 

The occupational noise regulation promulgated 

by OSHA,6

 as well as the limits published by 

NIOSH8

 and ACGIH,2 are designed to prevent 

hearing losses from exposures to intense noise 

levels. However, noise of intensities lower than 

that which may cause a loss of hearing can be 

disruptive in the workplace. Interference with 

speech is a possible result of unwanted noise. 

The noise can interfere with the efficiency and 

productivity of the staff and can be detrimental 

to the occupants’ comfort, health, and sense of 

wellbeing. One set of noise criteria for occupied 

interior spaces, the balanced noise criteria 

(NCB) curves, has been devised to limit noise to 

levels where satisfactory speech intelligibility is 

achieved.8, 9, 10 The noise criteria were devised 

through the use of extensive interviews with 

personnel in offices, factories, and public places 

along with simultaneously measured octave 

band sound levels. The interviews consistently 

showed that people rate noise as troublesome 

when its speech interference level is high 

enough to make communications difficult. The 

recommended space classifications and 

suggested noise criteria range for steady 

background noise heard in various indoor 

occupied activity areas are shown in Table 1. 

RESULTS

Field Survey 

Area noise analysis 

Area noise sampling was conducted in each of 

the three Kaiser Permanente facilities; twice at 

the Santa Teresa location to capture room noise 

on the day and the afternoon work shifts, and 

during the day shifts at Santa Clara and 

Redwood City. Spectral noise data were stored 

at each of the workstations, regardless of 

whether they were occupied by a 

transcriptionist. The measurement locations are 

noted in Figures 1-3. At Santa Teresa, results 

from the day shift and afternoon shift were 

generally consistent with each other. The day 

shift had a median value of 50.7 dBA and 

60.5 dB SPL while the afternoon shift had 

values of 49.6 dBA and 59.6 dB SPL. The 

overall values for Santa Clara were 48.4 dBA 

and 63.9 dB SPL, and 44.4 dBA and 55.0 dB 

SPL at the Redwood City facility. The thirdoctave band data were combined into octave 

bands to simplify their analysis and to compare 

the area room noise values to the NCB 

criterion.10 The octave band data for the three 

locations are shown in Figures 6-8. The NCB-45 

curve is representative of the room noise at 

Santa Teresa and Santa Clara. At Santa Teresa, 

the highest frequency octave bands slightly 

exceed the NCB-45 curve, while at Santa Clara, 

all of the room noise octave bands are less than 

the curve. At Redwood City, quieter conditions 

were measured so that the NCB-40 curve better 

represents the situation with the highest 

frequency band slightly exceeding the criterion. 

The room noise conditions at all three locations 

are characterized as reception or general 

secretarial areas (Table 1) and are much less 

than the NCB-60 maximum recommendation if 

communications must take place. 

Employee interviews 

A total of 24 employees from the three Kaiser 

Permanente facilities working on the days of the 

site visit were interviewed. This total includes 

the three HIM managers from each of the 
Page 6 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

facilities. Thirteen of 21 transcriptionists (62%) 

interviewed reported having some problem with 

the noise levels emitted by the C-phone. Their 

concerns centered on the system’s tones and 

beeps and the voice prompts, such as the voiced 

medical record number and end of record 

statement. Most felt that the volume control on 

the C-phone altered the physician’s dictation 

level, but had no effect on the tones and voice 

prompt signals. Many of the transcriptionists 

reported that the dictation sound level would 

drop as a result of a sudden, loud noise, such as 

a cough by the physician, and stay lowered for 

many seconds. To compensate for the lowered 

volume, they would increase the manual volume 

control. However, the dictation volume would 

unpredictably return to the previous volume 

setting exposing them to loud sounds until they 

could reset the volume control or remove the 

headsets. Six of the 21 transcriptionists (28%) 

reported symptoms they attributed to their 

employment, including hearing loss and tinnitus, 

along with headaches, stress, and feelings of 

depression. 

Laboratory Analysis 

Twenty different medical records from the three 

Kaiser Permanente locations were recorded and 

analyzed in the NIOSH laboratory. The average 

and peak sound levels from each of the 

recordings, the dial-tones, and the voice test 

signal are shown in Table 2. The Dictaphone Cphone volume dial was set for minimum, 

medium, and maximum. The medical records 

data from the three HIM departments are shown 

at maximum level to evaluate any possible 

excessive noise exposures. The unweighted 

average levels ranged from 65 dB SPL for the 

test message at the minimum setting to 107 dB 

SPL for the C-phone’s dial tone with the volume 

control set at maximum. 

The NIOSH RELs are highlighted in Table 3 for 

dial and test signals, as well as recordings from 

the three facilities. The results are presented as 

A-weighted values for the C-phone at minimum, 

medium, and maximum volume settings. The 

NIOSH REL for occupational noise exposure is 

85 dB, A-weighted, for an 8-hour time-weighted 

average (85 dBA as an 8-hr TWA) using a 3-dB 

exchange rate with an allowed noise dose of 

100% per day.8

 Exposure at or above this level 

is considered hazardous. The data analysis 

revealed that all of the tested conditions can be 

listened to at a safe level over an entire work 

shift. However, there are conditions with the 

volume control set at the maximum level where 

the sound delivered to the employee’s ears 

should be limited to only a portion of the work 

day because of the high intensity exposure. All 

three of the HIM department’s dictation 

examples exceeded the NIOSH REL when the 

volume control was at the maximum setting. 

Figure 9 shows average sound levels of the dialtone, foot-pedal, phone keypad touch-tones, the 

test message, and an average of the dictation 

recordings from each HIM department. The 

sound levels were obtained from the Dictaphone 

C-phone system with volume level set to 

medium. Identical distributions of the results 

were obtained with the C-phone set at minimum 

and maximum volume settings. 

Another test conducted in the NIOSH laboratory 

was to quantify the output of the Dictaphone 

headsets that are supplied with the C-phone and 

used at Kaiser Permanente. The frequency 

responses of the three headset models tested are 

shown in Figures 10-12. The y-axis shows the 

sound level in dB SPL and x-axis shows the 

frequency in Hz. A swept-sinusoidal signal was 

applied to each headset at 10 mV, 100 mV, 1 V, 

and 5 V. The corresponding output response is 

plotted in each figure. All three headsets exhibit 

increasing output levels as the voltage of the 

input signal is increased from 10 mV to 5 V. The 

Deluxe and Light models show relatively flat 

responses from 400 Hz to 5 kHz at all input 

levels. The Sound Band model varies across 

most of the frequency range. A comparison of 

the monaural performance of three headsets at 

10 mV is illustrated in Figure 13. 

DISCUSSION

The evaluations outlined in this report aimed to 

identify any potential hearing hazard to Kaiser 

Permanente transcriptionists generated by the 

Dictaphone C-phone system and headsets from 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 7 

actual dictated recordings. The recorded 

dictations were analyzed for any spurious spikes 

or unusually high noises using a playback 

method and a computerized impulsive noise 

detection software program. Although most of 

the recordings exhibited inconsistent dictation 

quality, none seemed to contain noises that 

might be considered immediately hazardous to 

hearing. 

Three common themes were identified among 

all the recordings: varying voice fluctuations by 

the medical dictator, isolated static and phone 

line noises, and calling from locations with high 

background noise. Because of the diversity of 

the medical staff, the many different dialects and 

accents from male and female medical dictators 

increased the listening difficulties for the 

transcriptionists. Several of the dictators spoke 

rapidly, particularly when dictating routine 

information, such as vital signs and demographic 

information. There were also instances where 

the physician was heard screaming for 

information (“where are the vital signs”) or at 

others in the room where the dictation was being 

done (“her arm”). These actions reduced the 

dictation volume for approximately 15 seconds 

before it reset to the original level with no 

warning. 

The results show that the highest noise levels 

were generated by the phone dial-tone, footpedal, keypad touch-tones, and the message 

header played at the beginning and end of each 

dictation (Figure 9). The dial tones measured as 

high as 101 dB SPL on mid-volume setting on 

the C-phone, the foot pedal at 91 dB SPL, and 

the message headers at 86 dB SPL. The NIOSH 

analysis also shows that the volume control 

setting on the C-phone did affect the intensity of 

the tones, beeps, and voice prompts (Table 3). 

The recordings from the HIM departments had 

average levels that ranged from 80-82 dB SPL. 

Tables 2 and 3 show that hazardous exposure 

can occur if the volume setting on the C-phone 

is set to maximum level, especially from the dial 

and touch tones. The results also show that the 

NIOSH REL can be reached within 

approximately 2-3 hours of listening to 

dictations at maximum levels. It is important to 

note that the REL will be significantly lower for 

those dictations when they are combined with 

the higher noise levels of the dial and touch 

tones. Conversely, the results also indicate that 

listening on the low-to-medium volume setting 

presents no hazard to hearing. 

The three headsets supplied with the C-phone 

were tested for linearity, quality of sound, and 

frequency response. Figures 10-12 show that all 

three headsets are capable of producing output 

levels in excess of 120 dB SPL. However, the 

maximum level produced by the headsets when 

connected to the C-phone is 110 dB SPL. This 

indicates the presence of some type of a noiselimiting circuit in the Dictaphone system. Even 

with the noise-limiting feature, the maximum 

output level is at a value potentially harmful to 

human hearing. It could be lowered to a level 

that has less potential for damage and still has 

enough volume to be heard by the 

transcriptionists in the environments where they 

work. Figure 13 shows that the Deluxe headset 

had the best flat response across the most 

frequencies while the other headsets exhibited 

significant degradation over their low and highfrequency response curves. These results are 

also comparable to previous studies that have 

shown insert-type headsets provide 7-9 dB of 

increased sound output than regular headsets.11 

Previous studies on telephone and call center 

operators found that the risk of hearing damage 

is minimal.12,13 In the call center study, the noise 

exposure of 150 operators from 15 call centers 

across a wide range of industry sectors were 

evaluated. The study found that while exposure 

to high-level noise was possible, the daily 

personal noise exposure was unlikely to exceed 

an 85 dBA hazardous exposure limit. In 

Australia, Patuzzi et al. and Milhnich and Doyle 

are conducting research to investigate other 

symptoms that allegedly result from exposure to 

acoustic shock events.14,15 These symptoms 

include tinnitus, pain, hypersensitivity to sound, 

vertigo, numbness/tenderness/soreness around 

the ear and neck, headache, fatigue, etc. Many of 

these symptoms were reported by at least one of 

the transcriptionists at Kaiser Permanente. Their 

research recognizes that sounds transmitted 
Page 8 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

through the headsets are generally incapable of 

damaging the ear directly. The authors believe 

the trauma is caused by excessive middle ear 

contractions typically triggered by stress and 

anxiety. For this reason, these authors believe 

that control measures targeted at limiting the 

sound produced by the headsets or modification 

of the equipment might be misplaced and that 

stress management strategies might be better 

suited for such situations. 

CONCLUSIONS

A noise exposure assessment was performed on 

the Dictaphone C-phone system and transcribed 

recordings provided by Kaiser Permanente to 

determine the presence of any hearing hazard 

associated with the use of such equipment. The 

C-phone had noise-limiting circuitry that 

lowered any peak sound level above 110 dB 

SPL. The highest noise levels were produced by 

dial and keypad tones which averaged 8-20 dB 

higher in intensity than the medical dictations. 

The dictations suffered from inconsistent quality 

and high background noise levels, which were 

factors of the location from which the doctors 

called and the type of telephones they used to 

dictate their messages. Noise exposure to 

dictations combined with the high-frequency 

tones played at the maximum volume setting 

was significantly higher than the 8-hour NIOSH 

REL of 85 dBA and could lead to noise-induced 

hearing loss if continued without intervention. 

When the volume control is set at the midposition or less, the noise exposures from all of 

the conditions tested in the laboratory are nonhazardous when compared to the NIOSH REL. 

The evaluation of the room noise at each of the 

three facilities indicates that these lower volume 

playback levels should be audible in the office 

environment where the transcriptionists work. 

RECOMMENDATIONS

The following recommendations are provided to 

reduce any hazard to hearing that is associated 

with the use of the Dictaphone equipment and 

work practices in the HIM departments at Kaiser 

Permanente. In general, NIOSH recommends 

that employers and workers implement a variety 

of control measures to limit worker exposure. 

The recommendations are based on the 

examination of the Dictaphone equipment, 

headsets, and the dictation recordings along with 

the assessment of the work environments and 

employee input at the three Kaiser Permanente 

HIM departments. 

1. Most of the headsets are adequate for 

their intended use. However, the quality and 

performance of the Deluxe Transcription 

Headset was vastly superior to the other 

headsets. Kaiser Permanente managers should 

consider recommending this headset to its 

employees. 

2. Work with the design engineers at 

Dictaphone to see if additional limiting circuitry 

can be included in either the C-phone or 

headsets to further reduce the maximum output 

levels from the current value of 110 dB SPL. 

The clarity of the dictation record must be 

maintained or improved throughout any changes 

made to the system. 

3. Consider migrating dictation services 

from the current phone-based system to a 

computerized, software-assisted system. If the 

dictations are stored in a WAV format on hard 

drive servers, they can be downloaded to a 

transcriptionist workstation for playback. In 

addition, WAV files can be scanned with 

software programs prior to listening for any 

instantaneous spikes or unusual noises and 

provide warning for problematic dictations. The 

WAV files can also be normalized to suit the 

preferred listening level of transcriptionists. A 

computerized dictation system could rely on 

visual interactivity features instead of using a 

foot pedal, thus eliminating one source of noise 

exposure. 

4. The Australian research studies 

mentioned in the discussion section provide 

some valuable insight into the discrepancies 

between the reported problems by 

transcriptionists and the lack of scientific 

evidence pointing to widespread hearing damage 

that would help to support their claims. It is 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 9 

entirely possible that this might be an issue of 

workplace stress and anxiety that in turn causes 

excessive middle ear contractions that lower the 

threshold for the manifestation of symptoms 

associated with acoustic shock and trauma. 

Kaiser Permanente management might want to 

further study employee stress and anxiety that 

may be attributable to the work environment. 

5. Continue the headset committee at 

Kaiser Permanente. This committee of 

transcriptionists and hospital management is a 

venue where concerns can be brought forward 

and acted upon in an open forum. Make the 

minutes of this committee available to all of the 

employees who work on the dictation and 

transcription of medical records. Interaction of 

this committee with the vendor who supplies the 

dictation equipment used by Kaiser Permanente 

may yield beneficial changes to the work 

environment. 

6. If such materials do not exist already, 

consider producing a training seminar, or printed 

materials for doctors advising them on proper 

dictation protocols. Doctors need to speak 

clearly and steadily, call from landline phones 

when possible, and call from quiet environments 

when feasible. 

7. The Cal-OSHA Information 

Memorandum issued March 5, 2004, noted that 

a continuing, effective hearing conservation 

program shall be administered if employee 

exposure to noise equals or exceeds 85 dBA as 

an 8-hr TWA (Appendix B). Because the 

transcriptionists depend a great deal upon their 

hearing to perform their job, it may be prudent 

to implement routine audiometric testing of 

these HIM employees to track their hearing over 

time even if the noise exposures are not great 

enough to trigger a hearing conservation 

program. If the guidelines set by Cal-OSHA for 

audiometric testing are followed, then 

management at Kaiser Permanente would have 

the required audiometric information if the 

documented noise levels are found to exceed the 

AL in the future. 

REFERENCES

 1. 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. 

 2. ACGIH [2004]. 2004 TLVs® and BEIs®: 

threshold limit values for chemical substances 

and physical agents. Cincinnati, OH: American 

Conference of Governmental Industrial 

Hygienists. 

 3. CFR [2003]. 29 CFR 1910.1000. Code of 

Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the 

Federal Register. 

 4. Ward WD, Royster LH, Royster JD 

[2000]. Anatomy & physiology of the ear: 

normal and damaged hearing. Chapter 4. In: 

Berger EH, Royster LH, Royster JD, Driscoll 

DP, & Layne M, eds. The noise manual. 5th ed. 

Fairfax, VA: American Industrial Hygiene 

Association, pp 101-122. 

 5. Suter AH [1978]. The ability of mildlyimpaired individuals to discriminate speech in 

noise. Washington, DC: U.S. Environmental 

Protection Agency, Joint EPA/USAF study, 

EPA 550/9-78-100, AMRL-TR-78-4. 

 6. CFR [2003]. 29 CFR 1910.95. Code of 

Federal Regulations. Washington, DC: U.S. 

Government Printing Office, Office of the 

Federal Register. 

 7. NIOSH [1998]. Criteria for a 

recommended standard: Occupational noise 

exposure (revised criteria 1998). 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. 98-126. 
Page 10 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

 8. Beranek LL [1989]. Balanced noise 

criterion (NCB) curves. J. Acoust. Soc. Am. 

86(2):650-664. 

 9. Beranek LL [1988]. Criteria for noise and 

vibration in communities, buildings, and 

vehicles. In: Beranek LL, ed. Noise and 

Vibration Control. Rev. ed. Cambridge, 

Massachusetts: Institute of Noise Control 

Engineering, pp. 554-623. 

 10. ANSI [1995]. American national standard: 

Criteria for evaluating room noise. New York, 

NY: Acoustical Society of America, American 

National Standards Institute, ANSI S12.2-1995. 

 11. Fligor BJ, Cox LC [2004]. Output levels of 

commercially available portable compact disc 

players and the potential risk to hearing. Ear and 

Hearing. 25(6):513-527. 

 12. Alexander RW, Koenig AH, Cohen, HS, 

Lebo CP [1979]. The effects of noise on 

telephone operators. Occup Med. 21:21-25. 

 13. Patel JA, Broughton K [2002]. Assessment 

of the noise exposure of call centre operators. 

Ann. Occup. Hyg. 46(8):653-661. 

 14. Patuzzi R, Milhinch J, Doyle J [2000]. 

Acute aural trauma in headset and handset users. 

Paper presented at the Neuro-otological Society 

of Australia National Conference, Melbourne, 

Australia. 

 15. Milhnich J, Doyle J [2000]. Acute aural 

trauma in headset and handset users. Paper 

presented at the 14th National Conference of the 

Audiological Society of Australia, Adeleide, 

Australia.
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 11 

Table 1 

Suggested Balanced Noise Criteria Range for Various Occupied Indoor Areas 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Type of Space and Acoustical Requirements NCB Curve 

Concert halls, opera houses, and recital halls 10 – 15 

Large auditoriums, large drama theaters, and large churches Not to exceed 20 

Small auditoriums, small theaters, small churches, music 

 rehearsal rooms, large meeting and conference rooms, 

 and executive offices Not to exceed 30 

Bedrooms, hospitals, residences, apartments, hotels 25 – 40 

Private or semi-private offices, small conference rooms, 

 classrooms, libraries 30 – 40 

Large offices, reception areas, retail shops and stores, 

 cafeterias, restaurants 35 – 45

Lobbies, laboratory work spaces, drafting and engineering 

 rooms, general secretarial areas 40 – 50 

Light maintenance shops, industrial plant control rooms, 

 office and computer equipment rooms, kitchens, 

 and laundries 45 – 55 

Shops, garages 50 – 60 * 

Work spaces where speech or telephone communication 

 not required 55 – 70 

* Levels above NCB-60 are not recommended for any office or communication situation. 
Page 12 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Table 2 

Unweighted Average and Peak Sound Pressure Levels 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Event Avg. Level 

(Leq in dB) 

Peak Level 

(Lpeak in dB) 

Comment 

Calibration Tone 94 97 B&K 4230 Calibrator (94 dB@ 1KHz) 

Dial Tone @Min. 86 92 Minimum level on C-Phone 

Dial Tone @Med. 101 107 Medium level on C-Phone 

Dial Tone @Max. 107 110 Maximum level on C-Phone 

Test Message @Min. 65 83 Minimum level on C-Phone 

Test Message @Med. 80 104 Medium level on C-Phone 

Test Message @Max. 93 109 Maximum level on C-Phone 

Foot Pedal @Max. 99 110 Foot-pedal at maximum level 

Message Header @Max. 99 109 Header at beginning of each message 

Touch Tones @Min. 73 87 Minimum level on C-Phone 

Touch Tones @Med. 80 101 Medium level on C-Phone 

Touch Tones @Max. 102 110 Maximum level on C-Phone 

Santa Teresa-7262361 95 109 Loud background noise throughout 

Santa Teresa-730882 96 110 Loud background noise 

Santa Teresa-731514 96 109 Volume surges throughout recording 

Santa Teresa-732769 92 109 Soft beginning, changing sound quality 

Santa Teresa-734715 94 109 Volume surges and vibration of sound 

Santa Teresa-735026 96 110 Volume surges and drops 

Santa Teresa-736121 96 110 Drops and then volume surges 

Santa Teresa-738814 94 109 Drops in volume 

Santa Clara-7335481 94 109 Static and high-pitched sounds 

Santa Clara-721246 94 110 Yelling into phone 

Santa Clara-705580 86 109 Soft dictation with loud noises 

Santa Clara-720197 93 109 Keypad loud noise spike 

Santa Clara-718385 95 109 Loud volume and coughing 

Santa Clara-704773 95 109 Voice raised and throat cleared 

Santa Clara-720779 94 109 Soft dictation then loud voice 

Redwood City-6632041 94 109 Soft speaking voice then loud 

Redwood City-663174 91 109 Soft speaking voice then loud 

Redwood City-738830 92 109 Soft speaking voice then some noise 

Redwood City-732279 94 109 Hit phone button at end of report 

Redwood City-730062 94 109 3 dB raise in volume in middle of report 

 

1

 Medical record dictations obtained with C-phone volume set at maximum level. Numbers represent the medical 

record identification number. 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 13 

Table 3 

A-weighted Noise Exposures and Dose Response 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

NIOSH Recommended Exposure Limits 

Event 

TWA (dBA) Recommended 

exposure duration 

Dose (%) 

Dial Tone – min 

 med 

 max 

82 

97 

103 

16 hours 

30 minutes 

7.5 minutes 

50 

1600 

6300 

Touch Tone – min 

 med 

 max 

69 

76 

99 

Safe 

Safe 

19 minutes 

< 20 

< 20 

2500 

Msg. Header – min 

 med 

 max 

66 

77 

96 

Safe 

Safe 

37 min 48 sec 

< 20 

< 20 

1300 

Foot Pedal – min 

 med 

 max 

69 

78 

99 

Safe 

Safe 

19 minutes 

< 20 

< 20 

< 20 

Test signal – min 

 med 

 max 

63 

72 

90 

Safe 

Safe 

2 hours 31 min 

< 20 

< 20 

317 

Santa Teresa – min 

 med 

 max 

65 

74 

91 

Safe 

Safe 

2 hours 

< 20 

< 20 

400 

Santa Clara – min 

 med 

 max 

62 

71 

90 

Safe 

Safe 

2 hours 31 min 

< 20 

< 20 

317 

Redwood City – min 

 med 

 max 

63 

71 

89 

Safe 

Safe 

3 hours 10 min 

< 20 

< 20 

250 
Page 14 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 1 

Floor Plan of HIM Department at Santa Teresa 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Hallway

Office Area

WS

WS

WS - Work Station

WS

Storage 

Cabinet

WS

WS

WS

WS WS

#1

#9

#No. – Noise Measurement Location

#2

#10

#3

#11

#4

#12

#6

#14

#5

#13

#8

#16

#7

#15
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 15 

Figure 2 

Floor Plan of HIM Department at Santa Clara 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Outdoors

Restroom Break Room

WS - Work Station

#No. – Noise Measurement Location

WS WS

WS

WS

WS WS

WS

WS

Supervisor

WS

#2 #1

#3

#4

#5
Page 16 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 3 

Floor Plan of HIM Department at Redwood City 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Hallway

Break Room Manager’s Office

WS WS

WS

WS WS

WS WS WS

WS WS

WS - Work Station

#No. – Noise Measurement Location

#1

#2

#3

#4

#6 #5

#7

#8

#9

#10
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 17 

Figure 4 

Test Setup of the Dictaphone C-Phone System Using KEMAR 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Figure 5 

The KEMAR Artificial Acoustic Fixture with B&K 4165 Microphones 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 
Page 18 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 6 

Octave Band Levels and NCB Curve for HIM Department at Santa Teresa 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

0

10

20

30

40

50

60

70

80

90

31.5 Hz63.0 Hz

125 Hz250 Hz500 Hz

1.00 kHz2.00 kHz4.00 kHz8.00 kHz16.0 kHz

Octave Band Center Frequency

Sound Pressure Level [dB SPL]

Room Octave Bands NCB-45
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 19 

Figure 7 

Octave Band Levels and NCB Curve for HIM Department at Santa Clara 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

0

10

20

30

40

50

60

70

80

90

31.5 Hz63.0 Hz

125 Hz250 Hz500 Hz

1.00 kHz2.00 kHz4.00 kHz8.00 kHz16.0 kHz

Octave Band Center Frequency

Sound Pressure Level [dB SPL]

Room Octave Bands NCB-45
Page 20 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 8 

Octave Band Levels and NCB Curve for HIM Department at Redwood City 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

0

10

20

30

40

50

60

70

80

90

31.5 Hz

63 Hz

125 Hz250 Hz500 Hz

1.0 kHz2.0 kHz4.0 kHz8.0 kHz

16.0 kHz

Octave Band Center Frequency

Sound Pressure Level [dB SPL]

Room Octave Bands NCB-40
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 21 

Figure 9 

Comparison of Averaged Sound Levels Generated by the C-Phone at Medium Volume Setting 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 

Dial Tone Foot Pedal Touch Tones Header Test Message Santa Teresa Santa Clara Redwood City

Average sound level (dB)

0

20

40

60

80

100

120
Page 22 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 10 

Frequency Response of the Dictaphone Deluxe Headset 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 23 

Figure 11 

Frequency Response of the Dictaphone Light Headset 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 
Page 24 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

Figure 12 

Frequency Response of the Dictaphone Sound Band Headset 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 25 

Figure 13 

Frequency Response of the Three Dictaphone Headsets at 10 mV 

Kaiser-Permanente 

California 

HETA 2003-0273;-0280;-0287 
Page 26 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

APPENDIX A 

OSHA Salt Lake Technical Center Report 

U. S. Department of Labor 

Occupational Safety & Health Administration 

Salt Lake Technical Center 

• Health Response Team 

• 8860 South Sandy Parkway 

• Sandy, UT 84070 

 Phone: 801-233-4900 

DATE: March 5, 2004 

MEMO FOR: SUSAN ECKHARDT 

 Industrial Hygienist 

 State of California OSHA 

THROUGH: ALAN TRAENKNER 

 Deputy Regional Administrator Region 9 

 San Francisco, CA Regional Office 

FROM: EMIL GOLIAS, MS, MPH, CSP 

 OSHA Health Response Team 

 Salt Lake Technical Center (SLTC) 

SUBJECT: Sound level evaluation at Kaiser Permanente Santa Teresa Medical Center and 

Santa Clara Medical Center in California. 

INTRODUCTION

On January 27, 28, and 29 Emil Golias of the OSHA Health Response Team and Allen Woo, an acoustics 

engineer, conducted sound level sampling on three Kaiser Permanente medical secretaries (medical 

transcriptionist’s) who perform transcription services for outpatient and inpatient records at their Santa 

Teresa and Santa Clara medical facilities. Sampling was conducted for the employees entire work shift 

and the sampling equipment was removed during the employees break periods. Observations and back 

up measurements of employee exposures and work practices were made during the entire sampling 

period. Sound level readings were taken for ambient noise background levels in the office areas and the 

levels recorded were well below 70 dBA. This ambient noise would not contribute to the employee 

exposure levels monitored. The sampled employee’s were utilizing Dictaphone Corporation C phone 

dictation and transcription systems with various headset styles. This report summarizes the sampling 

method used, sampling results and recommendations of feasible engineering and work practice controls 

that may be implemented to reduce employee occupational noise exposure. If I can be of further 

assistance, or if you have any questions, please contact me at 801-233-4910. 

Test Equipment and Procedure 

During the week of Jan 26, 2004 noise sampling was conducted utilizing the following methodology and 

equipment: 

1. Signal from the dicta-phone system was diverted to a signal splitting box. The box consists of a 

unity-gain non-inverting Op-amp (high input impedance and low output impedance with 2 nine 

volt battery power sources). It is capable of providing plus/minus 9 volt output. The purpose of the 

box is to split the signal from the phone to the operator’s headset and the monitoring headset 

without reducing the signal strength from the phone to either headset. 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 27 

2. The monitoring headset then is placed on the Head and Torso Simulator (B&K 4128 HATS) in the 

manner similar to how it is worn by the operator. The HATS simulates the average human head 

with a microphone positioned at the eardrum. 

3. The eardrum microphone is powered and by a B&K microphone power supply, B&K 2807. The 

acoustic signal received by the microphone is fed into the power supply and amplified. 

4. The amplified signal from the power supply is then fed into an ART IEQ 1/3 Octave 

Programmable Equalizer. The equalizer carries out the transfer function of the HATS eardrum 

sound pressure level to the diffuse field sound pressure level, so the sound level can be 

compared to the OSHA noise standard. 

5. The output from the equalizer is then fed to a B&K 4434 Noise Dosimeter which records the 

percent exposure to the OSHA noise standard. 

Results 

1. January 27, 2004, sampling the morning shift at Santa Teresa starting at 6:45 am and finishing at 

3:00pm. The dose for 7 hours of sampling was 1%. 

2. January 28, 2004, sampling the afternoon shift at Santa Teresa starting at 3:45 pm and finishing 

at 11:10 pm. The dose for 6 hours of sampling was 33%. It was noted that 18% of the 33% dose 

was obtained in a rather short period of time about 45 minutes. 

3. January 29, 2004, sampling the afternoon shift at Santa Clara starting at 12:15 pm and finishing 

at 8:15 pm. The dose for 6 hours of sampling was10%. 

Recommendation 

1. Evaluate the soft and/or hard wear that provides the prompt to the employees. It was observed 

that the sound pressure level between the prompt and the beep at the beginning and the end of 

the each transcription can be accessibly loud and annoying. Modify the soft and/or hard wear of 

the Dictaphone to reduce the difference between the transcription sound signal and the prompt 

sound signal. 

2. Insert a pair of electrical diodes, back to back across the speaker transducer, to put a limit to the 

acoustic output. 

3. Evaluate the existing headsets to determine if they are adequate for the purpose intended. 

Medical secretaries utilize numerous headsets the quality of which has not been evaluated in 

relation to the task being performed. Using poor quality headsets can expose the operators to 

higher sound levels and inferior sound quality than needed to complete the task. Provide 

headsets with limiting devices that are suitable for the task being done which will keep employees 

exposure to sound as low as possible. 

4. Require that the medical personal provide higher quality dictation. If the material to be transcribed 

is of poor quality with poor dictation, low sound level or garbled speech this causes the operators 

to increase the volume on the headsets to enable them to understand the material. This 

increases the employee exposure to sound. 

5. For those employees who suffer from impaired hearing a system should be developed where 

dictation that is garbled or of an excessively low volume will be passed on and handled in a 

different manner. 

6. If needed, contract with a consultation service which will provide the required workplace 

evaluations. 
Page 28 Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 

APPENDIX B 

Cal-OSHA Information Memoranda 
Health Hazard Evaluation Report No. 2003-0273; 2003-0280; 2003-0287-2974 Page 29 
DEPARTMENT OF HEALTH AND HUMAN SERVICES 

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through research and prevention

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