TECHNICAL REPORT

Paul K. Blake et al. 

July 2011 

Approved for public release; distribution is unlimited 

Personnel Radiation Exposure Associated with 

X-Rays Emanating from U.S. Coast Guard LORAN 

High Voltage Vacuum Tube Transmitter Units 

DTRA-TR-10-26 

 Defense Threat Reduction Agency 

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F A

1. REPORT DATE (DD-MM-YYYY)

31-07-2011 

2. REPORT TYPE

Technical report 

3. DATES COVERED (From - To)

5a. CONTRACT NUMBER

5b. GRANT NUMBER

4. TITLE AND SUBTITLE

Personnel Radiation Exposure Associated with X-Rays Emanating 

from U.S. Coast Guard LORAN High Voltage Vacuum Tube 

Transmitter Units 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

5e. TASK NUMBER

6. AUTHOR(S)

Blake, Paul K; Hall, Jeffery W; Severance, Charles; and Rusiecki, 

Jennifer. 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

DTRA (see block 9), 

 USCG Logistics, 2401 Hawkins Point Rd, Baltimore, MD 21226 

 USUHS, 4301 Jones Bridge Road, Bethesda, MD 20814-4799

8. PERFORMING ORGANIZATION 

REPORT NUMBER

10. SPONSOR/MONITOR'S ACRONYM(S)

DTRA RD-NTSN 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

Nuclear Technology Directorate 

Defense Threat Reduction Agency 

8725 John J. Kingman Road Stop 6201 , 

Fort Belvoir, VA 22060-6201

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

Approved for public release; distribution is unlimited. 

13. SUPPLEMENTARY NOTES

14. ABSTRACT

This report analyzes personnel radiation exposure associated with x-rays emanating from U.S. Coast Guard LORAN 

high voltage vacuum tube transmitter units that operated between1942-2010. Approximately 10,000 U.S. Coast 

Guard service members operated these units during this period of time and may have been occupationally exposed 

to this x-ray source. This report provides information concerning the service members’ probability of radiogenic 

disease and culminates with guidance regarding U.S. Coast Guard veterans filing non-presumptive radiogenic 

disease claims with the Department of Veterans Affairs. 

15. SUBJECT TERMS

United States Coast Guard, USCG, Department of Veterans Affairs, VA, LORAN, X-Ray, High Voltage Vacuum 

Tubes, Radiation Dose, Radiogenic Disease 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

Dr. Paul K. Blake

a. EPORT R

U

b.

A TRACT BS

U

c. THIS 

P E AG

U

17. IMITATION 

OF BSTRACT 

 L

 A

UU

18. NUMBER 

OF PAGES 

19b. TELEPONE NUMBER (Include area code ) 703 767-3384 
CONVERSION TABLE 

Conversion Factors for U.S. Customary to metric (SI) units of measurement. 

MULTIPLY BY TO GET 

 TO GET BY DIVIDE 

meters (m) 

kilo pascal (kPa) 

kilo pascal (kPa) 

meter2

 (m2) 

joule (J) 

joule (J) 

mega joule/m2

 (MJ/m2) 

*giga bacquerel (GBq) 

radian (rad) 

degree kelvin (K) 

joule (J) 

joule (J) 

watt (W) 

meter (m) 

joule (J) 

meter3

 (m3) 

meter (m) 

joule (J) 

Gray (Gy) 

terajoules 

newton (N) 

kilo pascal (kPa) 

newton-second/m2

 (N-s/m2) 

meter (m) 

meter (m) 

meter (m) 

kilogram (kg) 

newton (N) 

newton-meter (N-m) 

newton/meter (N/m) 

kilo pascal (kPa) 

kilo pascal (kPa) 

kilogram (kg) 

kilogram-meter2

 (kg-m

2

) 

kilogram-meter3

 (kg/m3) 

**Gray (Gy) 

coulomb/kilogram (C/kg) 

second (s) 

kilogram (kg) 

kilo pascal (kPa)

1.000 000 x E -10 

1.013 25 x E +2 

1.000 000 x E +2 

1.000 000 x E -28 

1.054 350 x E +3 

4.184 000 

4.184 000 x E -2 

3.700 000 x E +1 

1.745 329 x E -2 

tk

 = (tof + 459.67)/1.8 

1.602 19 x E -19 

1.000 000 x E -7 

1.000 000 x E -7 

3.048 000 x E -1 

1.355 818 

3.785 412 x E -3 

2.540 000 x E -2 

1.000 000 x E +9 

1.000 000 

4.183 

4.448 222 x E +3 

6.894 757 x E +3 

1.000 000 x E +2 

1.000 000 x E -6 

2.540 000 x E -5 

1.609 344 x E +3 

2.834 952 x E -2 

4.448 222 

1.129 848 x E -1 

1.751 268 x E +2 

4.788 026 x E -2 

6.894 757 

4.535 924 x E -1 

4.214 011 x E -2 

1.601 846 x E +1 

1.000 000 x E -2 

2.579 760 x E -4 

1.000 000 x E -8 

1.459 390 x E +1 

1.333 22 x E -1

angstrom 

atmosphere (normal) 

bar 

barn 

British thermal unit (thermochemical) 

calorie (thermochemical) 

cal (thermochemical/cm2

)

curie 

degree (angle) 

degree Fahrenheit 

electron volt 

erg 

erg/second 

foot 

foot-pound-force 

gallon (U.S. liquid) 

inch 

jerk 

joule/kilogram (J/kg) radiation 

 absorbed dose 

kilotons 

kip (1000 lbf) 

kip/inch2

 (ksi) 

ktap 

micron 

mil 

mile (international) 

ounce 

pound-force (lbs avoirdupois) 

pound-force inch 

pound-force/inch 

pound-force/foot2

pound-force/inch2

 (psi) 

pound-mass (lbm avoirdupois) 

pound-mass-foot2

 (moment of inertia) 

pound-mass/foot3

rad (radiation dose absorbed) 

roentgen 

shake 

slug 

torr (mm Hg, 00

 C) 

 *The becquerel (Bq) is the SI unit of radioactivity; 1 Bq = 1 event/s.

**The gray (Gy) is the SI unit of absorbed dose. 
DTRA-TR-10-26: Personnel Radiation Exposure Associated with X-Rays Emanating From 

U.S. Coast Guard LORAN High Voltage Vacuum Tube Transmitter Units

Table of Contents 

Executive Summary...................................................................................................................... 2

1. Introduction............................................................................................................................... 3

a. The Co-Authors’ Charge......................................................................................................... 3 

b. A Brief History ....................................................................................................................... 3 

c. Transmitter Set Evolution ....................................................................................................... 4 

d. Ionizing Radiation Sources-Power Amplifying Vacuum Tubes ............................................ 7 

e. Ionizing Radiation Sources-Vacuum Relays .......................................................................... 8 

f. Ionizing Radiation Safety Guidance........................................................................................ 9 

g. Ionizing Radiation Units....................................................................................................... 10 

2. Occupational Risk................................................................................................................... 12

3. Radiation Measurements........................................................................................................ 13

a. Measurement Chronology..................................................................................................... 13 

b. Personnel Measurements ...................................................................................................... 16 

c. Field Measurements .............................................................................................................. 17 

4. Radiation Depth Dose Analysis.............................................................................................. 20

a. Introduction........................................................................................................................... 20 

b. Depth Dose Curves ............................................................................................................... 20 

5. Radiation Dose Reconstruction and Associated Uncertainty ............................................. 23

a. Exposure Scenarios ............................................................................................................... 23 

b. Sources of Uncertainty.......................................................................................................... 25 

6. Radiogenic Disease Compensation ........................................................................................ 27

a. Radiogenic Disease ............................................................................................................... 27 

b. Illustrative Examples ............................................................................................................ 28 

c. Recommendations................................................................................................................. 32 

7. Conclusions.............................................................................................................................. 34

8. References................................................................................................................................ 35

9. Acknowledgements ................................................................................................................. 38

10. Co-Authors’ Biographies...................................................................................................... 39

Appendix 1: USCG LORAN Occupational Radiation Exposure Questionnaire

Appendix 2: NIOSH-IREP Website Screen Shots

Appendix 3: 38 CFR 3.311b – VA Nonpresumptive Radiogenic Diseases

Distribution List 

1
Executive Summary 

United States Coast Guard (USCG) veterans stationed at LORAN stations (LORSTA) from 

1942-2010 have expressed concern that their duties may have caused them radiogenic disease 

due to their occupational exposure to x-rays emanating from high voltage vacuum tubes. The 

time period of concern ranges from 1942 when the USCG began operating LORSTA Battle 

Harbor, through 2010 when USCG LORSTA operation ceased – removing this ionizing radiation 

source. In response to this concern, the USCG Commandant, CG-1133 commissioned this 

technical report of personnel radiation exposure associated with x-rays emanating from 

LORSTA transmitter units. 

Radiation measurements available for analysis included five distinct temporal collections: 1982, 

1987-1988, 1993-1999, 2003, and 2008-2011. These measurements provide verification of a 

valid radiation exposure hazard that could potentially be a source of occupational disease. 

Radiation measurements in late 1993 resulted in the installation during 1995 of acrylic-lead 

radiation shields between the high power vacuum tubes and the outer electrical equipment 

cabinet doors. Subsequent radiation measurements demonstrated that the radiation shields were 

effective in eliminating occupational exposure from these radiation sources, if the shields were 

maintained between the USCG maintenance personnel and the energized power amplifier 

(vacuum tube). 

Results from the USCG’s limited LORSTA personnel radiation dosimetry monitoring program 

in 1988 and 1994 demonstrated minimal personnel radiation exposure for monitored personnel, 

well within federal occupational radiation exposure limits and presumably was the rationale for 

not establishing a USCG LORSTA personnel radiation dosimeter program. Unfortunately, this 

limited personnel monitoring program did not address the case of an individual who may have 

performed exceptional high voltage vacuum tube operational and maintenance activities that may 

have resulted in significant ionizing radiation exposure. 

To assist USCG LORSTA veterans, their dependents, the Department of Veterans Affairs (VA), 

and the USCG, this report culminates in recommendations for the collection of veteran exposure 

scenario data and its subsequent use in radiation dose reconstructions. Radiation dose 

reconstructions are required, in the absence of radiation personnel monitoring data, to perform a 

probability of radiogenic disease causation calculation, which can lead to a VA radiogenic 

disease compensation decision. 

2
1. Introduction

a. The Co-Authors’ Charge 

In March 2010, the U.S. Coast Guard (USCG) Commandant, Division of Environmental Health 

& Industrial Hygiene, CG-1133 (Rusiecki) contacted the Department of Defense health physicist 

(Blake) responsible for atomic veteran personnel radiation dose reconstruction and requested 

assistance in analyzing ionizing radiation exposure data from USCG LORAN Station (LORSTA) 

operation. This division also requested the support of a USCG active duty member (Hall) and 

USCG veteran (Severance) experienced with LORSTA operations to collaborate on this 

technical report. Brief biographies of the four co-authors are provided at the back of this report. 

This request for data analysis arose from inquiries from the LORAN veteran community 

regarding concerns of potential radiogenic disease from occupational exposure to low-energy xrays arising from high voltage vacuum tubes used in LORAN AN/FPN-39, -42, -44, and -45 

transmitting units between 1942-2010. USCG personnel who operated and maintained these 

systems were not typically monitored for occupational personnel radiation exposure and 

consequently have become concerned that their unknown personal radiation exposures may have 

contributed to health risks. The intended audience of this analysis is USCG LORSTA veterans, 

their dependents, the Secretary of Veterans Affairs, and Commandant, U.S. Coast Guard. 

b. A Brief History

LORAN, short for LOng RAnge Navigation, was a terrestrial 

radionavigation system developed during World War II by the 

famous Radiation Laboratory at the Massachusetts Institute of 

Technology. The first version transmitted a single pulse with 

a carrier frequency in the 1950 Hz range and it was used 

during the war to guide Allied military ships and aircraft. 

After the war, this system was renamed Loran-A and, it was 

made available for public use. In 1958 the U.S. Coast Guard 

began operation on a new and separate low frequency 

LORAN-C system that transmitted a pulse train of eight or 

nine pulses with a carrier frequency of 100 kHz. 

Fig. 1: LORAN Support Unit, 

Wildwood, NJ 

In 1974 the Secretary of Transportation adopted LORAN-C as the official radionavigation 

system for coastal U.S. waters. On December 31, 1980, the Coast Guard terminated Loran-A 

operation. In the late 1980’s, at the request of the Federal Aviation Administration, the Coast 

Guard began a project to extend LORAN-C coverage from coast to coast in the continental U.S. 

By 1990, the Coast Guard operated LORAN-C stations in the U.S., its territories, and in "host 

nations" such as Italy, Japan and Turkey (Bruckner, 1992). Reported accuracy at that time was 

0.25 nm (450 meters) at 95% confidence level with 24 hour access (99.7% availability). A 

historical review of USCG LORSTA operations indicates that over 150 transmission stations 

existed, and over 10,000 USCG personnel served in them between 1942-2010 (Loranhistory.info website, 2010). A typical LORSTA was independently operated by one junior 

officer or warrant officer or senior enlisted and approximately 8-20 additional enlisted personnel, 

depending on the era and location of the station. Prior to 1990, it was not uncommon for 

3
LORAN-trained USCG Electronics Technicians (ET) to spend most of their active duty careers 

(20 plus years) at various LORSTAs. However, at LORSTA Engineering Centers and some 

overseas facilities (i.e. LORSTA Gesashi, LORSTA Hokkaido, LORSTA Sellia Marina) civilian 

electronic technicians were employed. 

A LORSTA consisted of a single transmission antenna and associated support units where 

USCG personnel worked and resided. LORAN-C antennas (monopole towers) were typically 

625 or 1350 ft in height – see figure 1. A smaller number of LORSTAs were designed with four 

695 ft towers arranged in a square, with wire hanging between the towers serving as the radiating 

antennas. Support quarters for the electronics cabinets and other gear were originally Quonset 

huts, and in recent years evolved into modern support buildings – see figure 1. Early LORAN-C 

stations had a separate transmitter building located at the base of the transmitting antenna and 

located 1,000 yards from the main building. 

LORAN-C operation supported both military and civilian users. For the U.S. military, naval 

ships and weapon systems (e.g. the fleet ballistic missile system) were the critical users along 

with military aircraft. Likewise, over 1.3 million civilian mariners had LORAN-C receivers and 

over 80,000 civilian aircraft were similarly equipped. 

Since 1994, when the Global Positioning System (GPS) was fully implemented via a network of 

24 satellites, Loran-C military and civilian radionavigation users have gradually migrated to this 

more widespread and increasingly popular system. The major advantage of GPS is increased 

location accuracy (advertised 7.6 meters) and world-wide coverage in all weather and at all 

times, when and where there is an unobstructed line of sight to four or more GPS satellites. 

However, GPS is vulnerable to intentional, unintentional, and natural interference. While the 

GPS signal is very high frequency, LORAN-C signals are low frequency. LORAN-C signals 

were also very high-powered, so they penetrated cities, buildings and densely foliaged areas 

where low level GPS signals could be blocked. From a practical perspective, LORAN was 

virtually unjammable because of its high power and is significantly more resistant to many forms 

of interference. 

However, in accordance with the 2010 Department of Homeland Security Appropriations Act, 

the U.S. Coast Guard terminated the transmission of all U.S. LORAN signals in 2010. This 

ended a system that the Coast Guard had proudly run for more than 67 years. The 2010 closure 

action reflected the President’s pledge to eliminate unnecessary federal programs (USCG, 2010). 

The last U.S. Coast Guard LORAN station 

was officially disestablished on 22 Mar 

2011 (COGARD LSU Wildwood NJ msg. 

221645Z Mar 11).

c. Transmitter Set Evolution 

USCG LORAN transmitter technology 

began with high voltage vacuum tube 

circuits that generated unwanted incidental 

x-rays. This problem was exacerbated 

during transmitter evolution as higher 

Fig. 2: AN/FPN-44 Transmitter Set 

4
voltages were applied to vacuum tubes in order to increase LORAN signal strength. After 

several decades of improvements, LORAN transmitters evolved into solid-state technology void 

of any vacuum tube amplifiers (see Table 1). 

The AN/FPN-44 (see Fig. 2) was the most advanced 

vacuum tube type transmitter featuring water-cooled 

power amplifiers and a walk-in high voltage power 

amplifier section. All tube type transmitting stations 

consisted of two transmitters and one antenna 

coupler/ dummy load. One transmitter was always 

on air while the other was kept as a ready standby. 

Fig. 3: AN/FPN-45 Transmitter Passageway 

The AN/FPN-45 transmitter (see Fig. 3) was the 

highest powered transmitter in the LORAN 

inventory. The technicians on the right side of this 

photograph are trying to locate the source of high 

voltage arcing in the power amplifier section. Arcing 

often occurred during tube bake-in procedures, and in conjunction with faults within tuned, 

power amplifier, and high voltage circuits of all vacuum tube transmitters. 

Table 1: USCG LORSTA Transmitter Sets

Nomenclature System Designed Terminated Peak Power KW 

 - Standard Loran 1942 1946 - 

CG-52330 Loran-A 1954 1950’s 100 

T-137 Loran-A 1954 1980 160 

T-137A Loran-A 1954 1980 160 

T-325 Loran-A 1954 1980 160 

T-138-A Loran-A Amp 1954 1980 1,000 

AM-701/FPN Loran-A Amp 1954 1980 1,000 

AM-1700/FPN Loran-A Amp 1956 1980 1,000 

AN/FPN-39 Loran-C 1957 1994 100 

AN/FPN-42 Loran-C 1962 1994 300 

AN/FPN-44 Loran-C 1963 2007 400 

AN/FPN-44 ATLS Loran-C 1963 2007 400 

AN/FPN-44B Loran-C 1980 2007 400 

AN/FPN-45 Loran-C 1963 2003 2,000 

AN/FPN-45/B Loran-C 198? 2007 2,000 

AN/FPN-64 Loran-C 1975 2010 800 

LORAN vacuum tube transmitters amplified their signals through multi-stage class AB or B 

vacuum tube power amplifier sections. These circuits operated in a parallel push-pull tuned tank 

circuit configuration and were sensitive to loading and tuning. They were often the source of 

arcing, and large variations in RF peak voltages that could add energy to the power amplifier 

plate circuit increasing the RF peak voltage. The antenna coupler at vacuum tube transmitting 

stations was manually tuned to match the output impedance of the transmitters to the antenna and 

dummy load. Tuning was usually accomplished during the installation of the transmitter or 

5
following changes to the antenna. These transmitters were unable to automatically tune for 

variations in antenna system characteristics i.e. changes to ground plane due to weather. 

The final generation of LORAN transmitters (AN/FPN-64) was 

significantly different than previous generations since it did not use 

vacuum tube amplifiers circuits eliminating the source of incidental 

ionizing radiation. Instead of amplifiers this transmitter used solid-state 

pulse compression technology consisting of half-cycle generator units 

which autonomously contributed a portion of the antenna output 

current. The only possible source of incidental ionizing radiation in this 

transmitter was a single vacuum tube lightning arrestor in the switch 

network. 

The AN/FPN-64 transmitter had other significant advantages over 

earlier generations: 

Fig. 4: 1st IPA tube 

 a cleaner output signal 

 a higher ratio of output power to supplied line power, resulting 

in significant savings in annual electrical power cost 

 less maintenance – no vacuum tubes to replace 

 an automatic pulse generating and control system, which 

allowed for unmanned and remote operations at some sites – a 

significant savings in manpower costs 

Unfortunately, the conversion cost per LORSTA ranged from $2 

million to $4 million. In the late 90’s, the Coast Guard began a 

LORAN-C recapitalization project, which included replacing the 

remaining high power vacuum tube transmitters with non-radiation 

emitting, solid state technology. In November 2007, the last west coast 

older generation tube transmitter was replaced at LORSTA St. Paul 

Island, Alaska. The more advanced AN/FPN-44 tube type transmitters 

continue to operate on the west coast until LORAN was shut down at 

LORSTA Narrow Cape, LORSTA Shoal Cove, LORSTA Tok, and 

LORSTA Williams Lake.

Fig. 5: 2nd IPA tube 

As shown in Table 1, the first three generations of LORSTA transmitter 

sets demonstrate the USCG’s desire to increase transmitter output power, 

and hence increase the useful area of signal coverage per LORSTA. The 

first generation design was based on a three power vacuum tube approach: 

1st intermediate power amplifier (IPA) tube, a 2nd IPA, and the final PA 

tube. The 1st IPA and 2nd IPA tubes typically used smaller applied voltages 

than the final PA tube. Since LORSTA output signal power is a function 

of applied voltage and current through a tube, which is defined by the tube 

manufacturer’s operating tube characteristics, the easiest method of 

increasing LORSTA signal output, is to increase the number of power 

amplifier units – where one unit consists of a 1st IPA, 2nd IPA, and final PA 

Fig. 6: PA tube 

(EIMAC 6696) 

6
assembly. In fact, the AN/FPN-44 and the AN/FPN-45 sets are essentially the same transmitter 

with progressively more power amplifier stages and consequently greater output power. 

In comparison, AM and FM radio station radiated power output is significantly less. In the U.S., 

the Federal Communications Commission (FCC) mandates 50 kW or less for AM stations, and 

100 kW or less for FM stations (North America broadcast station classes, 2010). 

d. Ionizing Radiation Sources-Power Amplifying Vacuum Tubes 

Any vacuum tube operating at several thousand volts 

or more can produce x-rays. X-rays arise when 

electrons are accelerated by an electric field between 

the polarized cathode (the emitting surface), through 

one or more grids controlling the flow of electrons, 

and are collected by the anode of the vacuum tube. 

This radiation source is known as bremsstrahlung 

radiation, or “braking radiation” and is the basis of 

clinical x-ray tubes. As shown in equation (1), the 

averaged radiation exposure (X) from a vacuum tube 

source is a function of the square of the applied 

voltage (v) multiplied by the tube current (i). The 

term (k) is a multiplicative constant and (T) refers to 

time period of interest. 

Fig. 7: Insertion of acrylic-lead radiation shield 

within PA tube Electrical Equipment Cabinet 

(1) X = dttitv

T

k

T

)()( 1

0

2



Fig. 8: LORSTA Transmitter PA Space – with 

energized tubes 

However, in the case of most high-power vacuum 

tubes, x-ray production is an unwanted product, and 

tubes are designed to minimize its production. USCG 

LORSTA transmitter units were designed to use a 

power amplification (PA) tube manufactured by 

Machlett, Inc. and/or EIMAC, Inc. (named for its two 

amateur radio operator founders in 1934 - Bill Eitel 

and Jack McCullough). In 1965, Eimac merged with 

Varian Associates and became known as the Varian 

Eimac Division. In 1995, this division was sold and is now 

known as CPI - Communications & Power Industries. 

(EIMAC, 2010). PA tubes are often described by the terms 

“triode,” “tetrode,” and “pentode.” These terms also 

indicate the number of grids. A triode has one grid, a tetrode 

has two grids, and a pentode has three grids. USCG 

LORSTA PA tubes used a triode design.

The first and second IPA tubes typically had peak applied 

voltages of less than 11,000 volts and were not significant 

sources of personnel x-ray exposure – since much of the 

Fig. 9: Close-up of energized PA tube – 

viewed thru Electrical Equipment Cabinet 

7
Fig. 10: Close-up of PA tube deionized water system 

(red tubing into bottom of anode container) 

bremsstrahlung radiation is attenuated by the tube’s glass envelope. However, the PA tube used 

an applied voltage of 21,500 volts (21.5 kVp), resulting in a peak x-ray energy of a 21.5 keV. 

This occurs since vacuum tube x-ray production produces a 

continuous x-ray spectrum with a peak energy based on the 

applied voltage across the tube. The average energy of the 

unshielded x-ray spectra is approximately 1/3 – 1/2 of the 

peak energy. From an x-ray protection viewpoint, a 21.5 

kVp source is considered a “soft” x-ray source that is 

relatively easy to shield. For comparison purposes, clinical 

diagnostic imaging x-ray units are often operated at 100 

kVp, and associated radiation shielding is typically lead 

sheets of approximately 1.5 mm in thickness. For USCG 

LORSTA tubes a lighter weight, plastic shield (commercial 

acrylic-lead) is sufficient. Shields of this nature were 

inserted in all USCG LORSTA PA electronic cabinets still using vacuum tube based transmitters 

in 1995.

The other key parameter in PA tube x-ray production is electronic current. The LORSTA 

AN/FPN-44/45 sets used EIMAC/Machlett 6696 triode tubes continuously operating at 21.5 kV 

with a peak current of 205 amperes (CPI, 2010). In comparison, clinical diagnostic x-ray tubes 

use currents of milliamperes for non-continuous operations. LORSTA tubes are considered high 

power. Clinical x-ray tubes are not. 

High power vacuum tubes are not unique to USCG LORSTA operations. The Coast Guard, the 

Department of Defense, and the commercial sector use a variety of high power vacuum tubes for 

numerous applications, which are frequently broken into two categories: 

 Power grid tubes (e.g. triodes, tetrodes, and pentodes) used in radio, shortwave, TV and 

LORSTA radiofrequency (RF) transmission 

 Microwave power tubes (e.g. klystrons, traveling wave tubes, ...) used in radar, linear 

accelerators 

It should be noted, that high power tubes in USCG/DoD radar systems can operate at potentials 

up to several 100 kilovolts, and USCG and military personnel maintaining and servicing these 

systems have performed their work without wearing personnel radiation dosimetry. 

e. Ionizing Radiation Sources-Vacuum Relays 

LORAN transmitters used high voltage vacuum relays (solenoid-actuated, electromechanical 

switches) to interrupt the flow of current (see Fig. 11). These switches were also a potential 

source of x-ray exposure (USCG, 1999). These switches were primarily located in the antenna 

coupler space. However in the AN/FPN-45 configuration, two relay assemblies are located at the 

far end of the transmitter near the antenna and antenna counterpoise terminals. In figure 12, the 

antenna coupler cabinet door was modified by cutting out the aluminum center, and installing 

Plexiglas in its place. This cabinet modification resulted in increased x-ray exposure outside the 

cabinet, but allowed for visual monitoring of vacuum switch operation. Vacuum switches had 

neon bulbs attached in order to detect RF to aid troubleshooting emergencies such as an antenna 

coupler failure. 

8
A separate room housing the antenna coupler was often used as a plenum for air-cooling the 

transmitters, and dummy load. The area was also used for storage, and the transmitter power 

amplifier vacuum tube water cooling racks in the AN/FPN-44/B configuration (see Fig. 10). 

These racks were located at the very back end of the transmitter near the antenna and 

counterpoise terminals. Unlike the AN/FPN-44/B, the earlier AN/FPN-44 had its cooling rack 

installed within the transmitter. All AN/FPN-45 transmitters had their six (three for each 

transmitter) cooling towers located within the transmitters. 

Although in later years, the high voltage vacuum relays were labeled with an x-ray warning (see 

Fig. 13), it is anecdotally reported that due to years of ignoring this concern, many LORAN 

maintenance personnel did not treat this warning seriously. Investigators have found that x-ray 

output from these devices is extremely variable and unpredictable (Greenhouse, 1972). Of the 

18 relays tested by these investigators, new ones, with notable exceptions were observed to pose 

less serious x-ray problems than used ones. This was expected, since the surface contacts of the 

switches usually deteriorate with use. 

Fig. 11: Vacuum switches at 

LORSTA Tok Antenna Coupler 

Room 

Fig. 12: Cooling Rack in 

AN/FPN-44/B Antenna Coupler 

Plenum Space 

Fig. 13: Vacuum Switch Warning Label 

f. Ionizing Radiation Safety Guidance 

Both the Department of the Navy and the Food and Drug Administration, which regulates x-ray 

emissions from television cathode ray tubes with peak operating voltage of approximately 40 

kVp use similar control standards: 

Radiation levels shall not exceed 0.5 mrem/hour at five centimeters (two inches) from external 

surfaces of cabinets or enclosures containing high power vacuum tubes (NAVSEA, 1983 &1991) 

USCG policy (USCG, 2006) is to keep x-ray exposures as low as reasonably achievable 

(ALARA) and to ensure that the authorized limits are not exceeded. The authorized limits for 

ionizing radiation exposure for USCG LORSTA personnel were promulgated by the 

Occupational Safety and Health Administration, OSHA (29 CFR 1910.1096): 

9
Table 2: USCG Occupational Radiation 

 Exposure Limits 

Rems per 

calendar quarter 

Whole body: Head and trunk; active blood-forming 

organs; lens of eyes; or gonads 

1 1⁄4 

Hands and forearms; feet and ankles 18 3⁄4 

Skin of whole body 7 1⁄2 

The USCG does maintain a small radiation personnel dosimeter monitoring program for x-ray 

technicians at USCG medical clinics (USCG, 2006). This medical clinic dosimeter program 

reflects a civilian standard of practice, where the x-ray fields are more penetrating (typically 100 

kVp or greater) and USCG technicians on occasion must expose themselves to radiation fields, 

while holding a patient during imaging. On two occasions (1998 and 1994), the USCG 

performed radiation personnel dosimetry monitoring for LORSTA personnel. Results of this 

limited monitoring program (summarized in section 3 of this report) demonstrated minimal 

occupational radiation exposure of LORSTA personnel, well within Table 2’s limits and 

presumably was the rationale for not establishing a USCG LORSTA personnel radiation 

dosimeter program. Unfortunately, this limited personnel monitoring program did not address 

the case of an exceptional individual, who may have performed maintenance activities near 

energized high voltage vacuum tubes that could result in exceptional radiation exposures. 

g. Ionizing Radiation Units 

There are many ionizing radiation units. However, only a limited number of the units are used 

within this report. US occupational exposure limits use historical radiation units (e.g. roentgen, 

rad, rem), while the rest of the world uses an international system (SI) of units (coulomb/kilogram, gray, seivert) – see Conversion Table in the beginning of this report. For purposes of 

radiation protection, the units of R, rad, and rem are often used interchangeably, as evidenced by 

how measurements were reported in section 3 of this report. However, for purposes of radiation 

risk assessment and estimation of probability of causation, the biological effectiveness of x-rays 

is assumed to be substantially higher than the biological effectiveness of higher-energy gamma 

rays (see section 6.b of this report). Definitions of ionizing radiation units cited in this report 

follow: 

 roentgen (R): The roentgen is the term used to describe radiation exposure. This 

term describes the amount of ionization in air. This is the unit that ion chambers 

measure. For x-ray exposure, this unit may be converted to rad, via a multiplicative 

factor of 0.876 (1R = 0.876 rad in air). For performing x-ray dose reconstructions, the 

conservative assumption is made that R = rad, which is in the veteran’s favor for 

purposes of radiogenic disease compensation. This assumption is also a standard health 

physics practice. As a consequence, health physicists may also report ion chamber 

measurements in units of rem or mrem.

 rad: Rad is the term used to describe radiation dose. It describes a specific amount of 

energy absorbed in a medium (human tissue, for example). 

10
 rem: Rem is the term used to describe equivalent or effective radiation dose. It is a unit 

that is the product of energy absorbed in human tissues and the quality of the radiation 

being absorbed (the ability of the radiation to cause damage). For radiation safety 

purposes, the quality of the radiation (e.g. the x-ray photon) is nominally defined as 1, 

and consequently, rad = rem. This is the unit used to report thermoluminescent 

dosimetry measurements.

Throughout this report, radiation units may be preceded by the prefix milli (m). This prefix 

divides a unit by a 1,000 and minimizes the use of lengthy decimal nomenclature (e.g. 0.0035 

rem vs. 3.5 mrem). 

11
2. Occupational Risk

Ionizing radiation emissions from high power vacuum tubes are but one of the known 

occupational hazards associated with USCG LORSTA operation. For example, the safety sheet 

insert for USCG LORSTA PA tubes (Varian, 1980 & 1993) lists the following hazards, if 

appropriate safety standards are not maintained: 

 HIGH VOLTAGE – Normal operating voltages could result in lethal electrocution. 

 RF RADIATION – Exposure to radiofrequency (RF) non-ionizing radiation may cause 

bodily injury (e.g. burns) under exceptional circumstances. Cardiac pace makers may be 

affected. Note, this was primarily a risk while in close proximity to the antenna and 

antenna coupler area during active signal transmission (Also see, Gailey, 1987). 

 X-RAY RADIATION – High voltage tubes can produce x-rays. 

 RADIOACTIVE CONTAMINATION – Small quantities of radioactive material were an 

internal component of vacuum tubes that became a potential inhalation/ingestion risk if 

the tube was broken. Note, AN/FPN-44 and AN/FPN-45 transmitters used OA2WA 

tubes (NSN: 5960-00-03-4880) containing Cobalt 60 or Nickel 63, and JAN4651WA 

tubes (NSN: 5960-00-262-0286) containing Krypton 85, Radium 226, or Nickel 63. 

 BERYLLIUM OXIDE POISONING – Dust or fumes from BeO ceramics used as 

thermal links with some conduction cooled power tubes are highly toxic. 

 GLASS EXPLOSION – Many electron tubes have glass envelopes. Breaking the glass 

can cause an implosion, which will result in explosive scattering of glass particles. 

 HOT WATER – Water used to cool tubes can reach scalding temperatures. Touching or 

rupture of the cooling system can cause serious burns. 

 HOT SURFACES – Surfaces of air-cooled radiators and other parts of tubes can reach 

temperatures of several hundred degrees centigrade and cause serious burns if touched. 

As in most industrial facilities other potential hazards also existed at USCG LORSTAs: 

 POLYCHLORINATED BIPHENYLS (PCBs) – a probable human carcinogen. The 

large electrical capacitors contained PCBs. There are anecdotal reports of personnel 

contamination events during capacitor fires or capacitor replacement. 

 CARBON TETRACHLORIDE – a probable human carcinogen. It was used as a facility 

solvent and cleaning agent. 

 TRICHLORETHYLENE – a probable human carcinogen. It replaced carbon 

tetrachloride as a solvent and cleaning agent. 

 ASBESTOS – a known carcinogen. It was used to insulate steam pipes in facilities, 

including berthing areas. 

 AGENT ORANGE – an experimental carcinogen and teratogen. May be harmful by skin 

contact. It was used as a defoliate in fields surrounding the transmitting antennas. 

 FALLING - A rather unique hazard associated with LORAN stations was the possibility 

of falling while conducting a climbing inspection tour of the 625 or 1350 ft transmitting 

antenna towers. To put this in perspective, the Washington Monument in D.C. (550 ft in 

height) is 70 feet shorter than a typical LORAN-C station tower. 

In summary, operating USCG LORSTAs had numerous known personnel hazards, but safe 

operation was typical, if appropriate training, safe guards, and oversight were exercised. 

12
3. Radiation Measurements

 a. Measurement Chronology 

Ionizing radiation measurements were made with various thin-window, radiofrequency (RF) 

shielded ion chambers, radiographic film, and solid-state, integrating thermoluminescent and 

optically stimulated luminescent dosimeters between 1982 and 2011. A chronological summary 

of available measurements follows: 

 Aug 1982 – USCG Environmental Health Officer (EHO), Pacific Area (J.M. Johnson) 

and CAPT M. Seales, USPHS health physicist investigate PA tube x-ray exposures at 

LORSTA Middletown AN/FPN-45 transmitter. LORSTA Middletown was chosen due 

to its convenient location (California), and since it was representative of other LORSTAs. 

Measurements were made with CAPT Seales’ ion chamber. Reported maximum 

intensity was 2.5-3.0 mrem/h on contact on the outer glass window of PA electrical 

equipment cabinet. The intensity dropped off rapidly to an undetectable level at 1 ft. 

from the cabinet surface. 

o Although these measurements exceeded USCG radiation safety guidance 

(NAVSEA, 1983), it was concluded that personnel exposure would not meet the 

threshold for initiating a personnel radiation dosimetry program, since USCG 

personnel would rarely be in the physical location to receive this exposure, and 

that USCG LORSTA staff were not at health hazard, with one possible exception. 

The one possible exception cited was for a staff member to be in close proximity 

to an energized PA tube with the glass window of the electrical equipment cabinet 

open. To evaluate this practice, the EHO proposed follow-up measurements. The 

EHO also noted that due to the low penetrating power of the PA tube x-rays, 

exposure to lens of eye is a potential concern – if the staff member is not wearing 

glasses or corrective lenses (EHO, 31 Aug 1982). 

 Nov 1982 - USCG EHO, Pacific Area (J.M. Johnson) and CAPT M. Seales, USPHS 

health physicist performed a follow-up visit to the LORSTA Middletown AN/FPN-45 

transmitter. The EHO noted that for staff individuals to receive significant PA tube x-ray 

exposure they would have to circumvent the electrical equipment cabinet interlock 

system, which would also engender the possibility of fatal electrical shock or severe skin 

burns. The EHO received anecdotal information that individuals had in fact circumvented the interlocks to perform emergent transmitter repairs, check for electrical arcing, 

or to make bias under-voltage adjustments. Other possible justifications proposed for 

opening the cabinet window were to insert a high voltage probe connected to an external 

oscilloscope. However, senior staff at LORSTA Middletown also stated that there was 

no appropriate justification for performing this open window procedure. Repairs on a 

“cold” transmitter take longer, due to the time required to turn off the unit to enter the 

cabinet, and then turn it on again, upon exiting the cabinet. The staff related a notch can 

easily be made in the window frame to allow for insertion of the high voltage probe. 

CAPT Seale measured 16 mrem/hr (with an open window) at about 1 foot from the 

surface of the cabinet. The EHO recommended that his chain of command institute a 

policy of specifically forbidding circumvention of the cabinet interlock system. 

 Jun 1987 – USPHS, FDA-CDRH performed a radiological survey using films and 

thermoluminscent dosimeters (TLDs) on the outside of the electrical equipment cabinet 

13
containing the energized PA tubes at LORSTAs in the Far East section and Dana, IN. 

TLDs were kept in place for a week, and then processed. Highest readings varied from 3 

– 8 mR/h. Based on these results, the USCG leadership determined that a LORSTA 

personnel dosimetry program be implemented 

 Dec 1987 – USCG Commandant (G-KOM-4) requests the Naval Dosimetry Center in 

Bethesda, MD provide personal dosimeters to six LORSTAs – Dana, George, Gesashi, 

Hokkaido, Iwo Jima, and Marcus. Dosimeter issue periods run from Feb/Mar – Sep/Nov 

of 1988. Results are tabulated in Table 3 of this report. 

 Dec 1988 – USCG Commandant (G-KOM-4) notes that the LORSTA personnel 

dosimetry monitoring program reported no significant personnel radiation doses, and 

consequently, the program was discontinued. 

 Jun 1993 – Ion chamber measurements of x-rays emanating from PA tubes at LORSTA 

George produce health concerns of onsite staff. 

 Nov 1993 – Officer in Charge (OIC) LORSTA George requests occupational medical 

monitoring be instituted. The OIC notes dose rates of 5 mrem/h, which exceed the 

applicable NAVSEA safety standard of 2.5 mrem/h (NAVSEA, 1983). Based on this 

request, the USCG leadership restarts a LORAN-C personnel radiation dosimetry 

program. Results are tabulated in Table 3 of this report. 

 Dec 1993 – CAPT Bill Van Pelt, USPHS, Health Physicist, FDA Pacific Region 

summarized the results of his December 2, 1993 radiation survey of LORSTA George to 

USCG leadership in a memo (Van Pelt, 1993): 

o The transmitter area consists of two transmitters located on either side of an 

approximately 30 foot long, 5 foot wide hallway. On either side of the hallway, 

the first 10 feet or so are taken up by controls and high voltage supplies. The last 

20 feet are taken up by the power section containing vacuum tubes... The walls 

and access doors of the hallway consist of approximately 1/8” aluminum. The 

power section is accessible from the hallway through 36” x 36” panel doors with 

28” x 35” x 1/8” glass panel inserts. There are seven of these doors per side (plus 

two smaller doors apparently housing non-PA tubes). ...The tubes are centered 

about 2.5’ above the deck, partially behind the glass and partially behind the 

aluminum door. 

o Ion chamber (Victoreen 440 RF/C) readings approximately one inch from the 

outer door panel ranged from 6 mR/h at the level of the center of the tube to less 

than 0.2 mR/h at the level of the deck or at the top of the access panel door. 

CAPT Van Pelt demonstrated that by placing a 7 mm thick piece of acrylic lead 

shielding (Clear-Pb) in front of his ion chamber at the highest point of radiation 

exposure that he was able to reduce the measured radiation level to zero. He 

recommended that radiation shielding be considered for installation at LORSTA 

PA spaces. 

 Mar 1994 – Dennis Swartz, Radiological Health Expert, FDA Midwest Region 

performed a radiation survey of LORSTA Dana (Kraeger, 1994). He was assisted by 

ETC Jeffrey W. Hall, USCG, OIC, LORSTA Dana. Measurements were taken by an ion 

chamber (Victoreen 440 RF/D) – see Table 4. Mr. Swartz noted that it was unlikely 

personnel would spend more than a few minutes of operation time within inches of the 

energized PA outer door panel (e.g. reading gauges). At the center of the passageway, 

maximum radiation exposure (at tube height) was 1.8 mR/h. ETC Hall estimated annual 

14
maintenance man-hours in the PA tube hallway were 865 h – shared by three technicians. 

Mr. Swartz also recommended shielding installation. 

 Oct 1994 – Chief Warrant Officer M. Jones visited LORSTA George. While performing 

ion chamber measurements, he concluded that the age of the PA tube (new or rebuilt) had 

no effect on output from the tube. A prototype Clear-Pb shield had been installed around 

a PA tube, and no detectable radiation was measured outside of the shield. He also notes 

the prototype shields were remarkably easy to install and remove. 

 May 1995 – USCG signs contract with Clear-Pb manufacturer (Nuclear Associates, Carle 

Place, NY) with a 4 month delivery date (Sep 1995) for 120 shields. Shields are to be 

shipped directly to affected LORSTAs. 

 Apr 1996 – Ms. Lynn Jenkins performs a follow-up ion chamber (Victoreen 440 RF/D) 

radiation survey of LORSTA Dana (Swartz, 1996). She remeasures the previous 

locations noted in Table 4 (Kraeger, 1994) and finds no detectable radiation, and 

concludes that the installed Clear-Pb shielding is effective. 

 Oct 1999 – Radiation survey of LORSTA Shoal Cove documents 1.2 rem/h emanating 

from high voltage vacuum tube switches located in antenna coupler area (USCG, 1999). 

The report recommends: 

o Rear of coupler unit should be posted as a “High Radiation Area”, 

o Restrictions on time on personnel working in this area, and 

o Installation of radiation shielding. 

 Mar 2003 – Richard Tell Associates, Inc. performed an RF and x-ray survey of the 

Canadian Coast Guard LORAN-C station at Williams Lake, British Columbia (Tell, 

2003). This station is similar in layout and equipage to U.S. LORSTAs and reported 

radiation exposures external to equipment cabinets of similar intensities. However, this 

survey did contain some unique radiation measurements inside the transmitter tube 

electrical equipment cabinets, in very close proximity to the PA tubes. Reported 

measurements of this very soft x-ray field varied from approximately 673 – 3,225 mR/h. 

 Nov 2008 and Apr 2009 – CDR Luis Benevides, USN, Science Advisor, Naval 

Dosimetry Center, Bethesda, MD performs a radiation survey of LORAN Support Unit, 

Wildwood, NJ using Navy DT-702/PD personnel radiation dosimeters and an ion 

chamber with associated electrometer. Upon removing the Clear-Pb shielding, he 

verifies previously reported radiation exposure values outside the PA cabinets. However, 

he also takes measurements inside the Clear-Pb shielding. Maximum radiation dose rates 

directly in front of the PA tube are: 

o Hs: 3.05 rem/h and Hd: 0.500 rem/h – indicating a soft x-ray source. 

These measurements inside the Clear-Pb shielding are consistent with Landauer, Inc. 

optically simulated luminescent (OSL) measurements performed at the Canadian 

operated LORSTA Williams Lake (Tell, 2003). 

 Oct 2009 – Rapiscan Systems Inc. performed a follow-on x-ray survey of the Canadian 

Coast Guard LORSTA at Williams Lake (Gray, 2009). Similar to U.S. LORSTAs, initial 

PA tube x-ray shielding was installed in 1995. Sometime in 2008, a second layer of 

shielding was installed, and this extensive survey (external to electrical equipment 

cabinet, 7 rows by 10 columns of 12” x 12” squares were measured), replicated the three 

shielding stages (no shielding, one layer, and two layers). A total of 210 consistent 

measurements. 

15
 Mar 2011 – Paul Blake and LCDR Burke, USN (DTRA), LCDR Hall, USCG (CG 

Logistics, Baltimore), ETCM Severance, USCG (retired) perform a radiation survey of 

LORAN Support Unit (LSU), Wildwood, NJ to verify radiation exposure levels 

emanating from high voltage vacuum relays. A rebuilt power amplifier vacuum tube was 

examined for evidence of electron etching supporting concerns of concentrated beams or 

increased radiation levels from older or rebuilt power grid vacuum tubes. Significant 

electron etching was found on the rebuilt tube anode, while none was found on a newly 

manufactured tube of similar operational hours. During the visit quiescent voltages of the 

power amplifiers were measured and meter circuits were calibrated so that accurate anode 

voltages could be measured using an oscilloscope and high voltage probe. The test 

indicated that anode voltages exceeded anode power supply voltages at peak half cycles 

by nearly 2 KV reflecting induced voltages from the power amplifier tuned circuit. Any 

increases in anode supply voltage not only increase radiation intensity but also increase 

the parasitic X-ray energy levels. Increases in anode voltages due to transmitter output 

network tuning or power amplifier balancing are exceptional maintenance scenarios that 

increase the risk of ionizing radiation exposure. The LSU was disestablished a few days 

after the survey (COGARD LSU, 2011). 

b. Personnel Measurements 

Fig. 15: DT-648/PD open 

holder with card inside 

Fig. 14: DT-648/PD worn on 

belt or attached to pocket 

In December 1987, USCG Chief, Environmental Health and Occupational Medicine (G-KOM-4) 

initiated a personnel radiation dosimetry program at six LORSTAs: Dana, George, Gesashi, 

Hokkaido, Iwo Jima, and Marcus. The Naval Dosimetry Center, located at Bethesda, MD 

provided DT-648/PD personnel radiation dosimeters on a six week issue period to the USCG 

LORSTAs. This naval dosimeter was capable of monitoring x-ray, gamma, neutron, and beta 

radiation (Devine, 1990). It was comprised of four LiF:Mg,Ti elements capable of measuring 

low energy photons and reporting both a shallow dose (the dose at a tissue depth of 0.007 cm (7 

mg/cm2

) and deep dose (the dose at a tissue depth of 1cm (1,000 mg/cm2) – see Figs. 14 and 15. 

This dosimeter was accredited by the National Voluntary Laboratory Accreditation Program 

(NVLAP) under the low energy photon category, and consequently was capable of measuring 

LORSTA x-ray radiation dose to both personnel and fixed point area monitors (NVLAP, 2010). 

As shown in table 3, the annual mean dose for monitored USCG LORSTA personnel was 0.005 

rem. Reported values for the 1988 exposure period were in shallow dose, and for the 1994 

period were in deep dose.

16
Station 1988 1994 Personnel Area Monitors Personnel Area Monitors Personnel Area Monitors

Kodiak N/A 07-08 5 6 0.000 0.295 0.000 0.066

Dana 03-11 N/A 9 0 0.001 N/A 0.009 N/A

Middletown N/A 03-07 22 4 0.000 0.525 0.000 2.100

George 03-10 07-09 13 4 0.000 1.059 0.000 4.236

Iwo Jima 08-09 N/A 9 1 0.003 0.200 0.027 0.200

Hokkaido 04-09 N/A 11 2 0.001 0.000 0.011 0.000

Marcus 05-10 N/A 11 0 0.000 N/A 0.000 N/A

Gesashi 02-10 N/A 8 2 0.000 1.722 0.000 3.444

Tok N/A 07-08 7 4 0.000 0.529 0.000 2.116

Attu N/A 07-08 10 4 0.001 0.259 0.010 1.036

105 27 0.001 0.489

0.005 4.236

Table 3: USCG Loran Station DT-648/PD Radiation Dosimetry Records

Weighted Mean Dose (rem)

Weighted Mean:

Annual Weighted Mean:

Exposure Periods Unique Individuals Mean - Rad. Dose (rem)

Four individuals had detectable radiation exposure (less than 5% of monitored personnel). The 

highest personnel dose over a six week issue period was 0.038 rem. This was a shallow dose 

measurement, and presumably the corresponding deep dose would be smaller. This extrapolates 

to a 0.082 rem/quarter or 0.329 rem/year – and well within the whole body, occupational 

radiation exposure limit of 1.250 rem/quarter (29 CFR 1910.1096). 

The USCG LORSTA DT-648/PD dosimetry results also include area monitor results. In the case 

of area monitors, personnel dosimeters are mounted in a fixed location during a dosimeter issue 

period. Area monitor data is more difficult to interpret, since distance and shielding between the 

radiation source and area monitor are required for interpretation. This information was not 

available for analysis, and consequently no significant conclusions may be drawn from this DT648/PD area monitor data. 

c. Field Measurements 

As noted in section 3.a, measurements of ionizing radiation fields were taken by a number of 

surveyors, at a number of LORSTAs, with a variety of radiation detectors, from 1982 through 

2011. Some of these measurements were made at single points, and others attempted areal 

measurements. Areal measurements were taken to address: 

 radiation field gradients: In relatively “uniform” radiation fields, radiation intensities 

gradually drop off with distance from some maximum exposure point, and 

 hot spots: “Non-uniform” radiation fields may result from “holes” in radiation shielding. 

In the case of electrical cabinet walls, which serve as radiation shielding for high voltage 

vacuum tubes, holes may have arisen at LORSTAs to allow for visual observation of a 

component or to allow an instrument (e.g. high voltage probe) access. 

Most early measurements were reported as point measurements around the power amplifying 

vacuum tubes. (e.g. CAPT Seales’ measurement of 2.5-3.0 mrem/h in August 1982). The only 

reported measurements of radiation from high voltage vacuum tube relays (switches) occurred in 

1999 and 2011. 

The first documented areal measurements (by ion chamber) 

occurred in March 1994 – see table 4. It was typical to 

identify the four high voltage vacuum tubes in a transmitter 

unit, as V1, V2, V3, and V4. Based on data reported in table 

4 and CAPT Van Pelt’s description of his radiation survey in 

December 1993, one can generally state that the maximum Fig. 16: Tube ID’s on exterior of 

PA electrical equipment cabinet 

17
radiation intensity at 0.5 cm from the outside of the electrical cabinet housing four energized 

high power amplifying vacuum tubes was at a height of approximately 34” and this radiation 

intensity gradually decreased to less than 1 mR/h at the level of the deck or the top of the access 

panel door. 

Table 4: LORSTA, Dana Radiation Survey Results (March 1994) 

Ion chamber measurements taken outside PA cabinet at heights from floor 

noted below and 0.5 cm from outer door panel (Clear-Pb shielding not in place)

Transmitter 19: 

Tube: V1 V2 V3 V4 

61” 0.1 mR/h 0.2 mR/h 0.5 mR/h 1.2 mR/h 

40” 1.4 mR/h 1.0 mR/h 3.0 mR/h 2.1 mR/h 

34” 4.4 mR/h 3.2 mR/h 7.9 mR/h 6.4 mR/h 

Transmitter 20: 

Tube: V1 V2 V3 V4 

61” 1.8 mR/h 4.5 mR/h 2.1 mR/h 3.4 mR/h 

40” 4.0 mR/h 5.6 mR/h 5.1 mR/h 5.5 mR/h 

34” 9.0 mR/h 12.5 mR/h 11.5 mR/h 11.5 mR/h 

The next set of areal measurements (by a Navy DT-702/PD thermoluminscent dosimeter) was 

performed by CDR Benevides in November 2008. He obtained measurements, without the 

Clear-Pb shielding in place, both within the PA electrical equipment cabinet (see Table 5) and 

also outside the cabinet (see Table 6). 

Table 5: LORSTA Wildwood Radiation Survey Results (Nov 2008) 

DT-702 measurements taken inside PA cabinet at heights from floor noted 

below and 0.5 cm from outer door panel (Clear-Pb shielding not in place)

Height from Floor Measurement 

45” 248 ±  mR/h 

35.5” 26.5 ±  mR/h

28” 18.7 ±  mR/h

23” 10.4 ±  mR/h

It is interesting to note that the maximum radiation intensity at LORSTA Wildwood is located at 

45” in height above the floor, while at LORSTA Dana the maximum intensity occurred at 34”. 

Table 6: LORSTA Wildwood Radiation Survey Results (Nov 2008) 

DT-702 measurements taken outside PA cabinet at 36” in height from the 

floor (Clear-Pb shielding not in place)

Distance from Cabinet Measurement 

0.5” 3.1 mR/h 

15” 1.2 mR/h

24” 0.8 mR/h

32” 0.5 mR/h

The DT-702/PD radiation dosimeter is an upgraded version of the Naval Dosimetry Center’s 

previous radiation dosimeter (the DT-648/PD). The DT-702 was introduced to improve beta 

particle determinations, as required by the national radiation dosimetry test standard (ANSI 

N13.11). It was comprised of four LiF:Mg,Cu,P elements capable of measuring low energy 

photons and reporting both a shallow dose (the dose at a tissue depth of 0.007 cm (7 mg/cm2) 

18
and deep dose (the dose at a tissue depth of 1cm (1,000 mg/cm2) – see Fig. 17. This dosimeter 

was also accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) 

under the low energy photon category, and consequently was capable of accurately measuring 

LORSTA x-ray radiation fields (NVLAP, 2010). The Benevides 2008 measurements were 

verified by Blake et al. in 2011 using a calibrated hand-held survey instrument shown in Fig. 18. 

Fig. 17: DT-702/PD card in open holder 

Fig. 18: Survey of PA Cabinet 

19
4. Radiation Depth Dose Analysis

a. Introduction 

As discussed in the previous sections of this report, the x-ray spectra emanating from LORSTA 

high voltage vacuum tubes is typically described as a “soft” spectra, where the lower energy 

photon component may be readily attenuated by a variety of materials before striking a USCG 

service member. There are also potential LORSTA scenarios where a relatively unfiltered x-ray 

spectra could strike a service member and a significant part of the radiation field would be 

absorbed by the veteran’s skin and not reach internal bodily organs. For these reasons, it is useful 

to a mathematically quantify these effects as input to radiation dose reconstructions for USCG 

LORSTA veterans. The well-know linear attenuation equation for radiation is: 

(2) I/I0 = ux Be

where: 

I/I0 is the number of transmitted photons/number of photons without absorber 

B is the buildup factor, which accounts for scattered radiations that are rescattered toward 

 location of interest 

 is the linear attenuation coefficient in cm-1

X is the absorber thickness in cm 

While  values are readily derived from tables of mass attenuation coefficients and material 

density, deriving low energy photon buildup factors is more problematic, since buildup is both a 

function of the attenuation coefficient  , itself a function of photon energy, and distance from 

the source of radiation. In recent years, low energy photon attenuation determinations have been 

facilitated through widely available probabilistic computational codes. 

b. Depth Dose Curves 

A variety of radiation transport codes exist that may model the unfiltered or filtered high voltage 

vacuum tube x-ray spectra transmission through the human body. Graphed data of this type is 

widely known as “depth dose curves.” The most widely used transport code for medical 

applications is Geant4, a toolkit for the simulation of the passage of particles through matter 

(Geant4, 2011). Geant4 is an open code developed by over 90 collaborators, distributed via the 

web for local workstation use, and cited in over 2,000 peer-review publications. 

In the three displayed depth dose curves that follow, millions of x-ray spectra photons were 

simulated to transit various materials (e.g. specified glass window filter and/or human tissue). 

This “Monte Carlo” simulation is based on the physics of x-ray photon interactions and material 

cross sections, and appropriately accounts for “buildup.” The results of this simulation are 

graphed at three unique depths (skin at 0.007 cm, lens of the eye at 0.3 cm, and other organs at 1 

cm) in the resulting figures: 

20
Fig. 19 Depth dose (0-100%) of an unfiltered 21.5 

kVp spectra in tissue 

Fig. 20: Depth dose (0-100%) of a 0.3 cm glass window 

filtered 21.5 kVp spectra in tissue 

Fig. 21: Depth dose (0 – 0.03%) of a 0.3 cm glass window filtered 21.5 

kVp spectra in tissue 

Figures 19, 20, and 21 were produced through 10 million photon history histogram simulations 

(Kramer, 2011). To reproduce the LORSTA PA tube 21.5 kVp x-ray spectrum for a Monte 

Carlo simulation, a probability distribution was created to translate a random number from a 

uniform distribution to the relative intensity spectrum desired. The function used for doing this 

was: 

21
(3) Eγ = Vp   )11(

where: 

Eγ is the randomly chosen photon energy weighted by the desired photon spectrum 

Vp is the peak energy of the photon spectrum in keV 

η is a random number chosen in a flat distribution from 0 to 1. 

Figures 19-21 demonstrate two significant points in comparing the filtered and unfiltered spectra: 

 The glass (or aluminum) cabinet wall will reduce the x-ray spectra radiation intensity by 

approximately three orders of magnitude (0.03%). This is consistent with ion chamber 

measurements performed 0.5 cm from the outer door panel of an operating PA cabinet 

where radiation measurements of a few rem/h (Benevides, 2008) had been attenuated to a 

few mR/h (Kraeger, 1994). 

 There is a significant difference between the depth dose from an unfiltered and filtered 

spectra. This is expected. For the same source intensity, the skin dose from an unfiltered 

spectrum would be higher than the skin dose from a filtered spectrum. The filter 

preferentially removes the lower energy “softer” x-rays, and the resulting “harder” x-ray 

spectra is more homogeneous. This difference is quantified in Table 7: 

Table 7: LORSTA Fractional Transmission Factors

Organ

Fig. 19-Unfiltered Spectra 

(Open Cabinet Scenario)

Fig. 21-Filtered Spectra 

(Closed Cabinet Scenario)

Skin 1.00 1.00

Lens of the Eye 0.06 0.72

Other Organs 0.01 0.40

22
5. Radiation Dose Reconstruction and Associated Uncertainty

a. Exposure Scenarios 

Principles and practices of personnel radiation dose reconstruction are well documented (NCRP, 

2009). The energized high voltage power amplifying (PA) tubes within their electronic cabinets 

and the high voltage vacuum tube switches were the USCG LORSTA radiation sources of 

concern. The next step in performing a personal radiation dose reconstruction (when personnel 

radiation dosimetry monitoring data is not available) is to develop an individualized radiation 

exposure scenario. To assist veterans in preparing individualized exposure scenarios, two 

sample exposure scenarios follow: 

Scenario No.1: Standard Operating/Maintenance Duties

LORSTA living and eating quarters were separate from the transmitter PA and vacuum tube 

switch spaces. Exposure only occurred when staff personnel were in or closely adjacent to these 

spaces. The mostly likely exposure scenarios occurred between 1995 and 2010, during 

maintenance activities near the energized PA tubes, before acrylic lead shields were installed. 

The following historical information (provided by two of the co-authors – Hall and Severance) is 

available:

Typical maintenance personnel staffing (gender: mostly male; especially in earlier years): 

 Two E-4’s (avg. age: 22 y) 

 One E-5 (avg. age: 26 y) 

 One E-6 (avg. age: 29 y) 

 One E-7 (avg. age: 33 y) 

Annual time in proximity to PA tubes: 

 Preventive maintenance: 220 h 

 Transmitter meter readings: 5 h Note: 5h ~1 min/d*5 d/wk*50 wk 

 Tube seasoning/balancing: 96 h 

 Corrective maintenance: 56 h 

 Total: 377 h (as compared to a typical work year of: 40h/wk*50wk/y = 2000 h) 

 Assume worker’s range of distance from active PA tube varied from 1-4 ft 

Occupational Radiation Dosimetry Results: 

 Maximum annual personnel dose was: 0.329 rem/y (see section 3.b, Table 4) 

Scenario No. 2: Exceptional Operating/Maintenance Duties

LORAN transmitter maintenance and engineering experts cite anecdotal reports of 

LORAN technicians performing exceptional operation/maintenance procedures that 

entailed significant radiation exposures (EHO, 1982, and Severance, 2011). It is not 

possible to create a standard scenario for universal application for these personnel. The 

exceptional scenario must be based on specific inputs from individuals. A few examples 

include but are not limited to: 

 Arc-watches over power amplifier vacuum tubes, or high voltage vacuum tube contactor 

circuits in order to localize arcing. 

23
 Transmitter interlocks bypassed and electrical cabinets opened allowing service members 

closer proximity to energized tubes exposing service members to unfiltered radiation. 

 Corrective or planned maintenance on the Antenna Coupler or Dummy Load exposing 

personnel to unshielded radiation from high voltage vacuum tube switches. 

 Occupation of the transmitter air plenum potentially exposing personnel to unshielded 

radiation from the Antenna Coupler/Dummy Load high voltage vacuum tube devices. 

 Vacuum tube seasoning procedures especially outside the transmitter in locally fabricated 

vacuum tube racks potentially exposed service members to radiation from tube arcing and 

anode current. 

 Vacuum tube equalized balancing routines within the transmitter during extended periods 

of exposure dwell time as vacuum tubes are replaced, swapped, and tested under load. 

 Power amplifier vacuum tube rebuild-program, resulting in rebuilt tubes emitting higher 

levels of radiation. 

 Removal of leaded glass due to breakage, equipment panel removal, and equipment panel 

modifications with acrylic glass in areas near high voltage vacuum tubes devices may 

have increased personnel exposures. 

 Corrective maintenance routines involving detuned tank circuit, transmitter loading, 

parasitic oscillations, etc. resulted in higher anode peak voltages and subsequent higher 

radiation energy levels. 

 Setting water leak, water vane, leakage current, high voltage contactor watch, or any 

other watches and activities in close proximity to the high voltage vacuum device. 

 Maintenance routines in the vicinity of high voltage vacuum tube amplifiers and high 

voltage vacuum switches when both transmitters are operating at full anode voltage, or 

drive increased exposures to service members. It was common for both transmitters to be 

running when working on RF amplification or balancing problems. 

 LORAN maintenance, repair, and certification teams from Far East Section Office 

(FESEC), Activities Europe (ACTEUR), South East Section Office (SEASEC), 

Philippines Section Office, and other Headquarters, District and Area offices. 

 Installation crews and installation teams of LORAN transmitters. 

 LORAN transmitter maintenance instructors at USCG Training Centers. 

 Engineers and electronic technicians at USCG Engineering Centers (EECEN), Loran 

Support Unit (LSU). 

 LORAN maintenance and repair teams on LORAN US Coast Guard support vessels such 

as USCGC Kukui (WAK-180) and USCGC Nettle (WAK-169). 

 LORAN transmitters that operated during the Cold War, Vietnam War, Korean War, 

World War II or during special evolutions i.e. nuclear tests, missile launches or NASA 

space launches demanded extremely high levels of equipment readiness and tolerances. 

Many LORAN chains operated for military service interests, i.e. Hawaiian Chain for the 

Pacific Missile Test Range and North West Pacific Chain for the Trident Missile 

Submarine Fleet, etc. These and other (often classified) operations requiring LORAN 

timing or navigation dictated extremely high levels of readiness and tolerances that often 

resulted in extreme maintenance routines. 

24
b. Sources of Uncertainty

The major source of uncertainty in LORSTA veteran radiation dose reconstructions arises from 

scenario no. 2. We have limited data associated with radiation exposures emanating from the 

LORSTA high voltage PA tubes and even less exposure data associated with LORSTA vacuum 

tube switches, and other high voltage vacuum tube devices such as arc suppressors. As 

described in sections 3.a and 3.c, these measurements varied over time and between individual 

tubes, and LORSTAs. In particular, as procedures changed, field changes were made, and 

radiation shielding was installed, radiation exposure scenarios evolved. Sources of uncertainty in 

terms of radiation exposure include: 

 The 3 rem/h dose rate measurement from an unfiltered PA tube reported by CDR 

Benevides in 2008 resulting from no glass window between the USCG service member 

and energized PA tube may have differed over time and at different facilities. This is the 

hypothesized dose rate associated with some of the anecdotal exceptional operation/ 

maintenance procedures. It is not unreasonable to assume an uncertainty of 2X (or an 

upper bound of 6 rem/h) for this measurement. 

 Duration of individual service member exposures while performing exceptional 

operation/maintenance procedures is a large source of uncertainty. It is not unreasonable 

to assume a conservative value while developing a service members’ exposure scenario. 

 Vacuum tube amplifier arcing - generating a short pulse of intense x-ray exposure. One 

unique source of arcing was unbalanced parallel amplifiers in push-pull circuits. There 

are reports in the literature of unanticipated high voltage transients exceeding the 

standard operating voltage (21.5 kVp) of PA tubes (Hunter, 1990). As noted in eqn. 1, 

since radiation exposure is a function of voltage squared, this could result in higher 

radiation exposures than previously measured. 

 Vacuum switch and other vacuum tube device arcing - generating a short pulse of intense 

x-ray exposure. 

 Detuned transmitter output circuits going unnoticed and generating increased anode 

voltages and arcing in power amplifier section. 

 Antenna coupler tuning mismatched to antenna causing large variance in radiation 

exposures between the standby transmitter in dummy load and operate transmitter into 

antenna. 

 Unreliable electromechanical voltage regulators with possibly higher than expected 

anode and bias voltages. These regulators were replaced by comparably more reliable 

solid-state regulators in the later years of LORSTA operation. 

 Evolving changes in vacuum tube manufactures, vacuum tube types, and vacuum tube 

rebuild programs, evidenced by the Mean Time Between Failure (MTBF) of older 

transmitters, and operational commitments of transmitters operated before 1995 requiring 

considerably more maintenance time resulting in increased exposure time. 

 High cost vacuum tubes such as the power amplifiers were often operated using 

unconventional methods to extend their life in order to save operating expenses. Older 

tubes inherently generating non-uniform and potentially increased radiation exposure, as 

do many rebuilt tubes. The power amplifier rebuild program was so successful that the 

manufacturer could no longer build new tubes at a reasonable price so the cost increased 

from $1,600 to nearly $8,000. This effect reinforced the use of rebuilt vacuum tubes that 

could be purchased for $3,000. 

25
In summary, unanticipated high voltage transients would most likely have occurred as high 

voltage vacuum tubes were nearing their end of their lifetimes. This is also when electrical 

arcing problems may have surfaced, and therefore was also when the service members may have 

performed exceptional operating/maintenance duties. Arc watch procedures in particular could 

last for hours, with the technician’s face against the glass window watching for arcs, or in rare 

cases, observing with an open window. 

26
6. Radiogenic Disease Compensation 

a. Radiogenic Disease 

Disease arising from exposure to ionizing radiation (radiogenic disease) is typically described by 

one of two exposure scenarios: 

1. Deterministic: characterized by acute exposures of 200 rad or greater, and typically 

manifesting acute radiation syndrome (ARS) symptoms from whole body irradiations 

of nausea, vomiting, headache, erythema, fatigue, epilation, and conjunctival 

reddening. During the history of USCG LORSTA operation, there have been no 

known reports of ARS. This fact establishes an upper bound on USCG LORSTA 

personnel radiation doses. There is at least one case where U.S. military members 

received high voltage, vacuum tube exposures that resulted in ARS. This occurred in 

March 1960 at a military installation in Lockport, New York from an unshielded 

klystron tube (UNSCEAR, 2008). 

2. Stochastic: characterized by non-acute exposures that may result in disease (e.g. 

cancer). Radiogenic disease latency periods (time between radiation exposure and 

diagnosis of disease) can vary between a few years for disease such as leukemia to 

decades for solid tumors. 

USCG veterans are eligible for Department of Veterans Affairs (VA) medical care and 

compensation due to health impairment resulting from their active duty. VA active duty 

determinations for reservists performing ADT (active duty training) versus IDT (inactive duty 

training) are beyond the scope of this report. Radiogenic disease resulting from active duty 

occupational radiation exposure is a recognized health impairment that can arise in veterans’ 

post-active duty service, due to radiogenic disease latency periods. 

Unfortunately, there are no unique biological markers that can distinguish between occupational 

radiation exposure and background radiation exposure (e.g. from natural sources or medical 

procedures). However, it is possible to calculate the risk or odds (probability) of developing 

radiogenic disease. The Health Physics Society provides a useful introductory table (HPS, 

2011): 

Table 8: Radiogenic Disease Summary 

No. of Cancers that occur over a lifetime 

in a population of 1 million people 

Odds of cancer (natural occurrence) 

Cancer 

Baseline 

420,000* 1 in 2.4 

Possible increase in cancer incidence caused by exposure to radiation above the naturally occurring background 

Dose No. of Cancers if 1 million people receive 

that dose over a lifetime 

Combined odds of cancers (natural occurrence 

+ additional risk from radiation dose** 

1 rem 421,700 1 in 2.4 

10 rem 437,000 1 in 2.3 

100 rem 590,000 1 in 1.7 

1,000 rem A person would die before cancer could occur 

27
*: Average male + female lifetime incidence (http://srab.cancer.gov/devcan) 

**: Adapted from ICRP 2007, Appendix A, Table A14 

Since it is often possible to estimate tissue-specific radiation doses with reasonable precision, the 

relationship between dose and subsequent cancer risk is probably better quantified than for any 

other common environmental carcinogen. The VA (38 CFR 3.3.11b) recognizes 24 nonpresumptive radiogenic diseases – see Appendix 3. An unlisted disease may be considered provided 

the claimant has cited competent scientific or medical evidence that the claimed condition is a 

radiogenic disease. 

b. Illustrative Examples 

For the VA to connect the veteran’s radiogenic disease to active duty occupational radiation 

exposure, a number of inputs are required, including: clinical documentation of the disease, date 

of the disease diagnosis, veteran’s sex (male or female), date of birth, radiation dose to the tissue 

of disease origin and associated periods of exposure during active service. These inputs are 

required for input into the Interactive Radioepidemiological Program (IREP) of the National 

Institute for Occupational Safety and Health (NIOSH), which is used by VA in adjudicating 

radiogenic disease claims (IREP, 2010). The VA uses IREP software, and in some cases, a 

review of the medical literature to develop a medical opinion, as to whether it is likely, unlikely, 

or as likely as not that the claimed disease is the result of exposure to ionizing radiation. 

Typically, VA requests the military service to provide the veterans’ radiation dosimetry records. 

These records are maintained in two locations, in the veterans health record, on the DD Form 

1141, “Record of Occupational Exposure to Ionizing Radiation” and in centralized military 

service repositories. However, since few of the USCG LORSTA service members were 

monitored for radiation exposure, a radiation dose reconstruction must, instead, be submitted. 

This reconstruction will be an estimate of the veteran’s radiation exposure, based on estimates of 

time, distance, and shielding of the veteran’s proximity to operating LORSTA high voltage 

vacuum tubes. Although these dose reconstructions should be conservative, providing the 

veteran benefit of the doubt in undocumented conditions, they should also take into account the 

known USCG personnel dosimetry results documented in table 3 of this report. 

As was discussed in section 4, LORSTA high voltage vacuum tubes produced low energy x-ray 

fields (e.g. photons E<30 keV). IREP incorporates an assumption that low energy x-rays are 

about twice as effective as high energy gamma rays (e.g. photons E>250 keV) in inducing cancer 

under the same conditions of exposure (Kocher, 2008). Specifically, IREP probability 

distributions for low energy x-rays at the 95% credibility level result in a radiation effectiveness 

factor, which represents their biological effectiveness, ranging from 1.1 to 6.1, with a median 

value of 2.4. This is reflected in the following examples: 

Example 1 (Ref: Sect. 5.a, Scenario 1): An ET2 (E-5), male service member (born: 

1939) performed engineering support at a USCG LORSTA from 1965-1968. He separated from 

the U.S. Coast Guard in 1968. In 2009, he was diagnosed with prostate cancer. In 2010, he filed 

a VA claim for service connection. Upon review of his historical duties, it was determined that 

no “exceptional” maintenance activities occurred during his LORSTA service. Therefore, the 

28
exposure scenario discussed in section 5.a of this report was assumed: 377 h in proximity to PA 

tubes. Assumed prostate exposure rate was 1 mrem/h. This results in 377 mrad/y (which 

exceeds the radiation exposures of any of the 105 LORSTA service members who were 

monitored for radiation exposure – see Table 3). The veteran’s NIOSH- IREP, ver. 5.6 manual 

entry calculation, based on Veterans Health Administration (VHA) guidance (Otchin, 2007) is 

shown below. Associated website screen shots are captured in Appendix 2: 

 https://www.niosh-irep.com/irep_niosh/

 

NIOSH-IREP input (ver. 5.6) manual entry: 

 Claimant Name: John Q. Doe 

 Gender: Male 

 Birth year: 1939 

 Year of Diagnosis: 2009 

 Cancer Diagnoses: Prostate Cancer 

 Cancer ICD-9 code: All Male Genitalia (185-187) 

Note: Malignant neoplasm of prostate is ICD-9 code: 185

 Alternate cancer model run? No 

 No. of exposures: 4 

 Dose input: 

1: 1965, Constant (0.377 rad), acute exp. rate, photons E<30keV 

2: 1966, Constant (0.377 rad), acute exp. rate, photons E<30keV 

3: 1967, Constant (0.377 rad), acute exp. rate, photons E<30keV 

4: 1968, Constant (0.377 rad), acute exp. rate, photons E<30keV 

NIOSH-IREP output: 

Probability of Causation (PC) 99th percentile: 4.08%. 

Note: This result is much less than 50%, and the VA medical opinion would probably

state it is unlikely that the prostate cancer can be attributed to exposure to ionizing 

radiation in service. The acute exp. rate option is veteran friendly, and its use is indicated 

in VHA guidance. Similarly, it is VHA guidance to enter conservative dose estimates, 

using the “Constant” option.

If this veteran had been diagnosed with acute myeloid leukemia (AML), keeping all other 

factors the same, the resulting PC 99th percentile: 10.89%. 

If this veteran had been diagnosed with a basal cell carcinoma (BCC) skin cancer, 

assuming an ethnic origin of white, non-hispanic, and keeping all other factors the same, 

the resulting PC 99th percentile: 15.94%. 

If this veteran had been diagnosed with posterior subcapsular cataract of the eye, an IREP 

calculation could not be performed, since IREP does not currently calculate a PC for this 

potential radiogenic disease. Instead, a medical opinion would be drafted, based on a 

review of the peer-review literature. 

29
Example 2 (Ref: Sect. 5.a, Scenario 2): An ETC (E-7), male service member (born: 

1932) performed supervisory engineering support at a USCG LORSTA from 1965-1968. He 

retired from the U.S. Coast Guard in 1972. In 2010, he was diagnosed with acute myeloid 

leukemia. In 2011, he filed a VA radiogenic disease claim. Upon review of his historical duties, 

it was determined that he had performed “exceptional” maintenance activities during his 

LORSTA service. During two of these years he had received up to 50 h of unfiltered exposure to 

the energized high voltage vacuum tube, and otherwise typical maintenance exposures (0.377 

rem/y). As indicated by CDR Benevides’ 2008 survey results, the unfiltered exposure rate was 3 

rem/h. However, to determine the bone marrow dose (the organ of interest for leukemia), we 

must take into account depth dose. From Table 7, we obtain a fractional transmission factor of 

0.01, which results in 1.5 rad to the bone marrow during the 50 h of unfiltered radiation 

exposure. However, there is significant uncertainty associated with this value, which is difficult 

to quantitate. Providing the veteran the benefit of the doubt, it is not unreasonable to assign an 

uncertainty of 2X this estimated dose value, resulting in an upper bound value of 3 rad to the 

bone marrow during the 50 h of unfiltered radiation exposure. 

NIOSH-IREP (ver. 5.6) input (manual entry): 

 Claimant Name: John Q. Doe 

 Gender: Male 

 Birth year: 1932 

 Year of Diagnosis: 2010 

 Cancer Diagnoses: AML 

 Cancer ICD-9 code: Acute Myeloid Leukemia (205.0) 

 Alternate cancer model run? No 

 No. of exposures: 4 

 Dose input: 

1: 1965, Constant (3.0 rad), acute exp. rate, photons E<30keV 

2: 1966, Constant (0.377 rad), acute exp. rate, photons E<30keV 

3: 1967, Constant (3.0 rad), acute exp. rate, photons E<30keV 

4: 1968, Constant (0.377 rad), acute exp. rate, photons E<30keV 

NIOSH-IREP output: 

Probability of Causation (PC) 99th percentile: 37.01%. 

Note: This result is less than 50%, and the VA medical opinion would state it is unlikely that the 

veteran’s acute myeloid leukemia can be attributed to his exposure to ionizing radiation in 

service.

If this veteran had been diagnosed with prostate cancer, keeping all other factors the 

same, the resulting PC 99th percentile: 15.60%. 

If this veteran had been diagnosed with a basal cell carcinoma (BCC) skin cancer, 

assuming an ethnic origin of white, non-hispanic, no smoking or non-ordinary radon 

history, and also assuming no depth dose drop-off (since target of interest is skin versus 

an internal organ), the applicable dose input becomes: 

30
NIOSH-IREP (ver. 5.6) input (manual entry): 

 Claimant Name: John Q. Doe 

 Gender: Male 

 Birth year: 1932 

 Year of Diagnosis: 2010 

 Cancer Diagnoses: BCC skin cancer 

 Cancer ICD-9 code: Lung (162) 

 Alternate cancer model run? No 

 Ethnic Origin: White-Non-Hispanic 

 Exposure Sources: Other Sources 

 Smoking History: Never smoked 

 No. of exposures: 4 

 Dose input: 

1: 1965, Constant (150 rad), acute exp. rate, photons E<30keV 

2: 1966, Constant (0.377 rad), acute exp. rate, photons E<30keV 

3: 1967, Constant (150 rad), acute exp. rate, photons E<30keV 

4: 1968, Constant (0.377 rad), acute exp. rate, photons E<30keV 

NIOSH-IREP output: 

Probability of Causation (PC) 99th percentile: 95.96%. 

If this veteran had been diagnosed with posterior subcapsular cataract (PSC) of the eye, 

an IREP calculation could not be performed, since IREP does not calculate a PC for this 

potential radiogenic disease. Instead, a VA medical opinion would be drafted, based on a 

review of the peer-review literature. To determine the PSC dose, we must take into 

account depth dose. From Table 7, we obtain a fractional transmission factor of 0.06, 

which results in 9 rem to the PSC during the 50 h of unfiltered radiation exposure. 

Similar to the other organ calculation, providing the veteran the benefit of the doubt, it is 

not unreasonable to assign an uncertainty of 2X this estimated dose value, resulting in an 

upper bound value 18 rem to the PSC during the 50 h of unfiltered radiation exposure. 

Total dose sums to: 18 + 0.38 + 18 + 0.38 = 37 rad. Recent studies of Chernobyl cleanup workers found that the maximum likelihood dose threshold for Stage I PSC was 35 

rad with a 95% confidence interval of 19-66 rad (Worgul, 2007). Consequently, a 

medical opinion in this case would probably note that it is likely that the claimed disease 

is the result of exposure to ionizing radiation. 

These results suggest that most USCG LORSTA veterans who performed standard 

operating/maintenance duties (see section 5.a, scenario 1) will probably not receive VA 

compensation for radiogenic disease, since their PC at the 99th percentile is less than 

50%. However, some USCG LORSTA veterans who performed exceptional operating/ 

maintenance duties (see section 5.a, scenario 2) may qualify for VA compensation, 

depending on the specific disease. However, this will strongly depend on the type of 

disease. For the LORSTA radiation scenarios, diseases such as skin cancer or PSC are 

more likely to be service-connected by the VA, while a disease such as prostate cancer is 

comparatively less likely to be service-connected. 

31
c. Recommendations 

 For USCG LORAN service members concerned about their potential occupational 

personnel radiation exposure: 

o Contact their local USCG healthcare provider for further information. 

 For USCG LORAN veterans (first time filers) claiming entitlement to VA disability 

compensation due to radiogenic disease arising from active duty service: 

o Complete a VA Form 21-526, Veterans Application for Compensation and/or 

Pension, and attach (if available): 

 Discharge or separation papers (DD214 or equivalent) 

 Dependency records (marriage & children's birth certificates) 

 Medical evidence (doctor & hospital reports) 

o This documentation can be submitted online or via a local VA Regional Office 

(VARO) 

o For assistance, call toll-free: (800) 827-1000 

 For USCG LORAN veterans (previously denied VA service connection) for disability 

compensation due to radiogenic disease arising from active duty service: 

o May refile based on new information presented in this technical report. The 

veteran should contact the VA Regional Office and request that the claim for 

service connection be reopened. The veteran should cite this technical report as 

the basis for the reopened claim, i.e., new and material evidence. 

 For the surviving spouse of a deceased USCG LORAN veteran wishing to submit a 

dependency and indemnity compensation (DIC) claim,: 

o The surviving spouse should complete a VA Form 21-534 for an original claim. 

If an original claim has been filed in the past, and denied, then the surviving 

spouse can reopen the previously denied claim by submitting new evidence (i.e., 

this technical report) DTRA-TR-10-26. 

 For the Veterans Benefits Administration (VBA) which has centralized processing of 

radiogenic disease claims at VARO, Jackson, MS (VBA, 2006). 

o Upon receipt of a USCG LORAN veteran claim for radiogenic disease, VARO 

Jackson should request the veteran complete a LORAN Occupational Radiation 

Exposure Questionnaire (see Appendix 1), 

o Upon receipt of this completed questionnaire, forward a request to Commandant, 

U.S. Coast Guard (Attn: CG-1133) for the veteran’s occupational radiation 

exposure records, 

o Upon receipt of CG-1133 response, VARO Jackson should submit the records to 

the Under Secretary for Benefits (Director, Compensation Service), for review. 

The Under Secretary for Benefits may request an advisory medical opinion from 

the Under Secretary for Health (Director, Environmental Agents Service). 

Fig. 22: VA Regional Office, Jackson, MS 

32
 For the Veterans Health Administration (Director, Environmental Agents Service) who is 

located in Washington, DC: 

o Use the scenarios cited in sections 4 and 6 of this technical report as guidance in 

performing their medical opinion. Chief, Nuclear Test Personnel Review, 

Defense Threat Reduction Agency is available for technical consultation. 

 For Commandant, U.S. Coast Guard, Division of Environmental Health & Industrial 

Hygiene (CG-1133): 

o Upon receipt of VARO Jackson’s request for a USCG LORAN veteran’s 

radiation exposure records, first verify if the veteran is one of the 105 LORAN 

veterans for which occupational radiation exposure records exist. Then forward 

the VA provided LORAN Occupational Radiation Exposure Questionnaire to 

Chief, Electronic Navigation Division, Commandant (CG-5532) for a 

technical/historical consult. Upon receipt of CG-5532’s review, forward results 

to VARO Jackson. 

 For Commandant, U.S. Coast Guard, Division of Electronic Navigation (CG-5532): 

o Upon receipt of CG-1133’s consult request, initiate a technical/historical review. 

The goal of this review is to determine whether the information provided in the 

veteran’s radiation exposure questionnaire is valid and representative of standard 

operating/maintenance duties or exceptional operating/maintenance duties. Title 

38 of the Code of Federal Regulations, section 3.102, “Reasonable doubt” 

provides the following guidance, “It is the defined and consistently applied policy 

of the Department of Veterans Affairs to administer the law under a broad 

interpretation, consistent, however, with the facts shown in every case. When 

after careful consideration of all procurable and assembled data, a reasonable 

doubt arises regarding service origin, the degree of disability, or any other point, 

such doubt will be resolved in favor of the claimant.” Results of the review should 

be returned to CG-1133.

33
7. Conclusions 

Approximately 10,000 USCG service members stationed at LORAN stations from 1942-2010 

could potentially have been exposed to occupational ionizing radiation exposure. Numerous 

radiation surveys during this period of time document x-ray fields emanating from high voltage 

vacuum tubes. Twice during this time period, USCG personnel stationed at LORAN stations 

were monitored for personnel radiation exposure. Results of this monitoring indicated that 

radiation exposure received by these personnel was within required safety exposure guidelines. 

However, there are numerous anecdotal reports of LORAN veterans performing exceptional 

operation/maintenance procedures which potentially entailed significant radiation exposures. As 

a consequence, there are two discrete scenarios of service member radiation exposure: 

 the majority of the LORAN service members who received minimal occupational 

ionizing radiation exposure, and 

 a smaller group of LORAN personnel who performed "exceptional" maintenance 

activities (and were not monitored with personnel radiation dosimeters). This group 

potentially received significant ionizing radiation doses. There is also significant 

uncertainty associated with this scenario. 

Recommendations, guidance and documentation are provided to assist USCG LORAN veterans 

and their dependents, the Secretary of Veterans Affairs and the Commandant, United States 

Coast Guard in responding to USCG LORAN veteran VA radiogenic disease claims. 

 

34
8. References

ANSI (American National Standards Institute) N13.11 - 1983, "Personnel Dosimetry 

Performance - Criteria for Testing”.

Bruckner, D.C., LT, USCG, 1992. Automatic Pulse Shaping with the AN/FPN-42 and 

AN/FPN-44A LORAN-C Transmitters, Naval Postgraduate School Thesis, 

Monterey, CA. 

Cassata, J.R., Moscovitch, M., Rotunda, J.E., Velbrick, K.J. 2002. A New Paradigm in 

Personnel Dosimetry Using LiF:Mg,Cu,P. Radiat. Prot. Dosim., 101, 1-4, 27-42. 

CFR (Code of Federal Regulations) Part 29, Section 1910.1096, Occupational Safety and 

Health Standards, Toxic and Hazardous Substances, Ionizing Radiation

 (http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10098

accessed 27 Aug 2010) 

CFR (Code of Federal Regulations) Part 38, Section 3.311, Claims based on Exposure to 

Ionizing Radiation (http://edocket.access.gpo.gov/cfr_2004/julqtr/pdf/38cfr3.311.pdf accessed 30 

Aug 2010). 

CPI (Communications and Power Industries) EIMAC ML-6696A tube specification sheet 

(http://www.cpii.com/docs/datasheets/79/3CW60-000D3-ML-6696A.pdf accessed 03 Dec 2010). 

COGARD LSU (Coast Guard LORAN Support Unit, Wildwood, NJ) 2011. Message of 

221645Z MAR 11 “Disestablish LORAN Support Unit.”

Devine, R.T., Moscovitch, M., Blake, P.K. 1990. The U.S. Naval Dosimetry Center 

Thermoluminescent Dosimetry System. Radiat. Prot. Dosim., 30, 4, 231-236. 

EHO (USCG, Pacific Area, Environmental Health Officer). 31 Aug 1982 Memo to 

Commander, Pacific Area – X-Ray Exposure at USCG LORAN Stations. 

EHO (USCG, Pacific Area, Environmental Health Officer). 06 Oct 1982 Memo to 

Commander, Pacific Area – X-Ray Exposure at USCG LORAN Stations. 

EIMAC products historical summary (http://en.wikipedia.org/wiki/Eimac accessed 03 Dec 2010). 

Gailey, P.C. 1987. Modeling and Measurement of Electromagnetic Fields Near LORANC and Omega Stations, (The EC Corporation, Oak Ridge, TN). 

Geant4 website (http://geant4.cern.ch/ accessed 12 Jan 2011). 

Gray, W.M. and Norris, S.T. 2009 X-Ray Radiation Survey and Evaluation Report for the 

Williams Lake, British Columbia LORAN-C Site. 

Greenhouse, N.A., Peterson, G.C. 1972. An Evaluation of Radiation Hazards from HighVoltage Vacuum Interrupters. Health Phys., 23 85-88. 

HPS (Health Physics Society) website (http://www.radiationanswers.org/radiation-and-me/radiationcancer/odds-of-cancer.html accessed 11 Jan 2011). 

Hunter, E.B. 1990. X-Ray Emission from Broadcast Transmitters. IEEE Trans on 

Broadcasting, 36, 1, 14-23. 

IREP (Interactive Radioepidemiology Program)(https://www.niosh-irep.com/irep_niosh/ accessed 

30 Aug 2010). 

Jones, M. 1994, Message to OIC LORAN Station Dana reporting results of his October 

1994 survey of LORAN Station Dana. 

35
Kocher, D.C., Apostoaei, A.I., Henshaw, R.W., Hoffman, F.O., Schubauer-Berigan, 

M.K., Stancescu, D.O., Thomas, B.A., Trabalka, J.R., Gilbert, E.S., Land, C.E. 

2008. Interactive Radioepidemiology Program (IREP): A Web-Based Tool for 

Estimating Probability of Causation/Assigned Share of Radiogenic Cancers. 

Health Phys., 95(1) 119-147. 

Kraeger, J.A. 1994. Radiation Survey, Loran Station, Dana. 

Kramer, K. 2011. ARA/HS-TN-11-006-B, Energy Deposition Curves for Communicating 

Health Risks about U.S. Coast Guard LORAN Station Vacuum Tubes.

Loran-history.info website. (http://www.loran-history.info/default.asp accessed 29 Aug 

2010) 

NVLAP (National Voluntary Laboratory Accreditation Program), Ionizing Radiation 

Dosimetry Accreditation Field. (http://www.nist.gov/ts/ssd/nvlap/nvlap-fields.cfm

accessed 29 Aug 2010). 

NAVSEA (U.S. Navy, Naval Sea Systems Command) 1983. SE000-00-EIM-100, 

“Electronics Installation and Maintenance Book”. 

NAVSEA (U.S. Navy, Naval Sea Systems Command) 1991. S0420-AA-RAD-010, 

Radiological Affairs Support Program Manual, Sec. 9.3, “Klystron and Cathode 

Ray Tubes”. 

NCRP (National Council of Radiation Protection & Measurements) 2009. Report 163, 

Radiation Dose Reconstruction: Principles and Practices, Bethesda, MD. 

North America broadcast station classes (http://en.wikipedia.org/wiki/List_of_broadcast_station_classes 

accessed 04 Dec 2010). 

Otchin, N.S. 2007. IREP Briefing at Veterans’ Advisory Board Meeting on Dose 

Reconstruction in Las Vegas, NV on 07 Mar 2007. 

Severance, Charles, “VA Buddy Letter”, (http://www.loran-history.info/health/health.htm accessed 14 

Jan 2011). 

Swartz, D.E. 1996. Follow-up Radiation Survey, Loran Station, Dana. 

Tell, R. 2003. X-Ray Dosimetry Measurements at Loran Station, Williams Lake. 

UNSCEAR (United Nations Scientific Committee on Effects of Atomic Radiation), 2008. 

Sources and Effects of Ionizing Radiation, Vol. II, Annex C, pg. 9, paragraph 66. 

USCG (U.S. Coast Guard), 1999. Commanding Officer, Integrated Support Command, 

Ketchikan, AK ltr. to Commanding Officer, LORSTA Shoal Cove, 21 Oct 1999. 

USCG (U.S. Coast Guard), 2006. COMDTINST M5100.47, Safety and Environmental 

Health Manual, Chapter 7, “Coast Guard Radiological Health Program” 

(http://www.uscg.mil/directives/cim/5000-5999/CIM_5100_47.pdf accessed 27 

Aug 2010)

USCG (U.S. Coast Guard), 2010. Navigation Center, LORAN-C General Information

(http://www.navcen.uscg.gov/loran/default.htm accessed 10 Jun 2010) 

Van Pelt, W. 1993. Radiation Survey, Loran Station, George. 

Varian, EIMAC Division, 1980. Power Grid Tube Operating Hazards Insert Sheet, San 

Carlos, CA. 

Varian, EIMAC Division, 1993. Power Grid Tube Operating Hazards Insert Sheet, San 

Carlos, CA. 

36
VBA (Veterans Benefits Administration), 2006. VBA Fast Letter 06-20, “Centralization 

of Radiation Claims Processing” Washington, DC. 

Worgul, B.V. et al. 2007. Cataracts among Chernobyl Clean-up Workers: Implications 

Regarding Permissible Eye Exposures Radiat. Res. 167, 233-243. 

37
9. Acknowledgements 

 CDR Dana Thomas, USPHS – former Chief, Occupational Medicine (CG-1133). She 

initiated this review at Coast Guard Headquarters, and remained heavily involved despite 

transferring to a follow-on duty assignment. 

 CDR Gary M. Thomas, USCG – former Commanding Officer, USCG LORAN Support 

Unit, Wildwood, NJ, who currently serves as Chief, Electronic Navigation Division, 

COMMANDANT (CG-5532). His historical knowledge and dedicated support were 

invaluable in compiling this report. 

 MCPO Bill Dietz, USCG, Retired and ETC Joe Jester USCG, Retired who maintain the 

LORAN history website. 

 The LORANIMAL community of the United States Coast Guard, who proudly stood the 

watch for over 67 years. 

Fig. 23: LSU Wildwood – 17 Mar 2011 

38
10. Co-Authors’ Biographies

Paul K. Blake 

Paul Blake is the program manager of the Nuclear Test Personnel Review (NTPR) Program, 

Research and Development Directorate, Defense Threat Reduction Agency, Fort Belvoir, Va. 

DTRA safeguards America’s interests from weapons of mass destruction by controlling and 

reducing the threat to the United States and its allies, and providing quality tools and services for 

the warfighter. In this capacity, he leads the Department of Defense’s efforts to confirm 

participation and reconstruct radiation doses for veterans involved in U.S. atmospheric nuclear 

weapons testing (1945 to 1962), and the post-World War II occupation forces of Hiroshima and 

Nagasaki, Japan. He also serves as DTRA’s representative on the Veterans’ Advisory Board on 

Dose Reconstruction – a federal advisory board that provides recommendations to the 

Department of Defense and the Department of Veterans Affairs. 

Dr. Blake is a retired United States Navy captain, having served 26 years active duty. During his 

time in the Navy, he initially served aboard the USS Fulton (AS 11) and the USS Samuel 

Gompers (AD 37). In his first shore assignment, he served as head, Radiation Dosimetry 

Division, Armed Forces Radiobiology Research Institute. Upon completing his doctoral studies 

in 1986, he reported to the Naval Dosimetry Center as science advisor. He co-designed and 

implemented the Navy’s personnel radiation dosimeter – the DT-648/PD. In 1989, he transferred 

to Naval Hospital Portsmouth as staff physicist and radiation safety officer and later served as 

head of his Radiology Department. 

In later duty assignments he served as head, Radiological Controls Branch, on the staff of Chief 

of Naval Operations and as the Surgeon General’s specialty leader for radiation health while 

assigned to the Bureau of Medicine & Surgery. In 2002, he returned to the Naval Dosimetry 

Center as officer in charge and supervised the implementation of the Navy’s next generation 

radiation dosimeter – the DT-702/PD that monitors over 50,000 workers. In 2004, he briefly 

served on the faculty of the Uniformed Services University of Health Sciences before retiring 

from active duty. 

Dr. Blake is a diplomate of the American Board of Health Physics and is a member of the U.S. 

Naval Institute and Health Physics Society. He earned a bachelor’s degree in chemistry and a 

master’s degree in health physics from Rutgers, the State University of New Jersey. During his 

graduate studies at Rutgers University he served as a Health Physics Fellow at Brookhaven 

National Laboratory in Long Island, N.Y. He later earned a doctorate degree in medical physics 

from the University of Wisconsin-Madison. 

Jeffrey W. Hall 

Lieutenant Commander Hall is serving as the Logistics Department Head at Coast Guard Sector 

Baltimore, MD. As Logistics Department Head, LCDR Hall manages supply & finance, naval & 

civil engineering, and personnel management as well as serving as the Commanding Officer of 

Military Personnel for more than 300 active duty and reserve members. 

LCDR Hall has more than 29 years of active duty in the Coast Guard. In addition to tours aboard 

Coast Guard Cutters ALERT and SPENCER, CG ACADEMY, TISCOM, and two tours at Coast 

39
Guard Headquarters, he served 15 years in the LORAN community. Beginning in 1982, he 

served at LORSTAs Port Clarence, AK; Dana, IN; OMEGA Station Kaneohe, HI; and on 

LANTAREA Coordinator of Chain Operations staff located at LORSTA Seneca, NY. In his 

capacity as an electronics technician, he has over nine years of experience maintaining the 

AN/FPN-42, AN/FPN-44B, and AN/FRT-88 vacuum tube-type transmitters. He attended the 

LORAN-C Engineering Course in New London, CT in 1989. 

During his tour as Officer in Charge of LORSTA Dana, IN, he documented x-ray emissions from 

the AN/FPN-44B transmitters with the assistance of the Food and Drug Administration office in 

Chicago, IL. These findings, along with those at LORAN Station George, WA led to the design 

and installation of clear lead-embedded acrylic shielding in the transmitters to mitigate the 

exposure to operating and technical personnel. 

LCDR Hall was selected for the Advanced Computers and Engineering Training (ACET) 

program from 1996-1998 where he received his Associates of Applied Science in Computer 

Engineering. He received his B.S. in Information Resource Management from University of 

Maryland University College in 2005 and is currently taking graduate courses in Information 

Assurance at Wilmington University. 

Charles Severance 

Master Chief Severance served twenty-years in the US Coast Guard. He is retired and resides 

with his wife Andrea, and five children in Wasilla, AK. He is a member of IEEE, and was a 

member of the Loran Wild Goose Association. He graduated from Loran Engineering School 

and taught Loran Engineering focusing on transmitters for three years. He retired as the School 

Chief for Electronic C-Schools that include LORAN, Radar, and communications. He was also 

the Subject Matter Expert for the ET rate and wrote the service wide exams and end of course 

tests. ETCM Severance also served at COMMSTA Kodiak, Far East Section Japan (LORSTA 

Gesashi, LORSTA Iwo Jima, LORSTA Yap, LORSTA Hokkaido, LORSTA Marcus, and 

Commando Lion). ETCM Severance also served two tours at TRACEN Governors Island NY, 

one as Section Chief for Loran-C, and one tour as LORAN-A instructor. His first two tours of 

duty were Loran-A stations LORSTA Cape Christian Baffin Island and LORSTA Pt Grenville. 

During the past seven years he has been working as an advocate for LORAN parasitic x-ray 

exposure awareness. Prior to his arrival in Alaska he worked as Washington State Electrical 

Administrator, Chief Engineer, and Operations Manager. As Electrical Administrator he was 

responsible for ensuring compliance with the National Electrical Code, OSHA safety regulations, 

and Washington State laws and safety guidelines pertaining to electrical contracting. While 

working as Chief Engineer he was responsible for the design, and compliance of all electrical 

projects, and bids. Responsibility for Operations Manager included managing, training and safety 

of staff of IBEW electricians and independent contractors. The job included bidding on new 

contracts, and management of a just in time inventory supporting all operations in the state of 

Washington. 

40
41

Jennifer Rusiecki 

Jennifer Rusiecki completed a Ph.D. in epidemiology from Yale University, School of Medicine 

and a post-doctoral fellowship in epidemiology at the National Cancer Institute, Division of 

Cancer Epidemiology and Genetics, in the Occupational and Environmental Epidemiology 

Branch. Currently an Associate Professor of Epidemiology at the Uniformed Services University 

(USU), she has worked in the Department of Preventive Medicine since 2005. She teaches the 

Occupational and Environmental Epidemiology course at USU and is involved in teaching 

Epidemiology Methods and Chronic Disease Epidemiology. 

Her research focus includes studies of occupational and environmental exposures and risk for 

various cancers; epigenetic influences of environmental exposures, particularly pesticides and 

heavy metals; and health of emergency responders. She has analyzed health effects data from the 

Coast Guard responder population who were involved in the Hurricane Katrina disaster response, 

and she is currently focusing on the Deepwater Horizon responder cohort from the Coast Guard. 

A graduate of the Coast Guard Academy, she served on active duty from 1989 to 2005. 

Currently, a Commander in the Coast Guard Reserve, she supports the Directorate of Health, 

Safety and Work Life at U.S. Coast Guard Headquarters.
 U. S. Coast Guard

LORAN Occupational Radiation Exposure Questionnaire

 SECTION I: PARTICIPANT CONTACT INFORMATION 

Name: Service Number/Social Security Number: 

Mailing Address: 

Telephone/Email: 

If this questionnaire is completed by someone other than the participant, please provide: 

Name: 

Mailing Address: 

Telephone/Email: 

Relationship to veteran: 

SECTION II: ASSIGNMENT SUMMARY (LORAN-A and/or LORAN-C)

Duty Station Dates Assigned Rate (ET1, SK2, etc) Names of other personnel (up to four) assigned 

During these dates, were there any times you were not involved in transmitter operations? 

Yes (explain) No 

Which of the following best describes your assignment(s)? More than one answer is possible. 

___ Administrative Support (FS, SK, HS) 

___ Command Cadre (CO/OIC, XO/XPO) 

___ Engineering (EM, MK, DC) 

___ Maintenance Technician (ET3 - ET1) 

___ Technical Management (ETC or above) 

___ Engineering, Development, or Project Staff (EECEN/LSU, Installation Teams, etc). 

HQ USCG, CG-1133 (Jul 2011) Page 1 of 4 Pages 
HQ USCG, CG-1133 (Jul 2011) Page 2 of 4 Pages 

SECTION III: DUTIES, RADIOLOGICAL MONITORING, & PROTECTIVE EQUIPMENT 

(LORAN-A or LORAN-C) 

The following questions are intended to assess your potential for occupational radiation exposure. Please provide 

details for answers to the best of your recollection (qualify as “approximate” as necessary). Use back or a 

separate page with reference to question number if more space is needed. If you are unable to answer a question 

or provide details, state “Unknown.” 

MAINTENANCE DUTIES 

 Did you perform/observe preventive and/or corrective maintenance to the transmitter (to include arc 

watches) or antenna coupler? 

o If so, how many days each year did you work in or near the transmitter or antenna coupler? 

o For each day you performed maintenance, how many hours were spent working on the equipment, 

in general? 

o For each day you performed maintenance, how many hours were spent near the final power 

amplifier section? 

o For how many years did you carry out this type of work? 

 Did your duties require you to work beyond interlocked sections of the transmitter? 

o If so, how many days each year did you work within the restricted area? 

o For each day you worked within the restricted area, how many hours were spent working on the 

equipment, in general? 

 Did you perform “tube seasoning/tube bake-ins”? 

o How many tube seasoning events did you ever perform? 

o During a typical tube seasoning event, how many hours were spent near the equipment? 

 Did you perform engineering testing (EECEN/LSU, Wildwood, NJ)? 

o If so, how many times per year did you take transmitter readings? 

o How many total transmitter readings did you take during all your assignments? 

o How many days each year did you work in or near the transmitter? 

o For each day you performed maintenance, how many hours were spent working on the equipment, 

in general? 

o For each day you performed maintenance, how many hours were spent near the final power 

amplifier section? 

o How many total years did you work in or near the transmitter? 
HQ USCG, CG-1133 (Jul 2011) Page 3 of 4 Pages 

SECTION III - (CONTINUED)

OPERATIONS DUTIES 

 Did you observe and record transmitter meter readings (“daily readings”)? 

o If so, how many times per year did you take transmitter readings? 

o How many total readings did you take during your all your assignments? 

RADIOLOGICAL MONITORING 

Were you issued a radiation dosimeter during your tour?

PROTECTIVE EQUIPMENT 

 During your tour(s) of duty at a LORAN Station (to include EECEN/LSU), did the transmitters have clear, 

lead-embedded acrylic shields installed in the final Power Amplifier section? 

o If yes, were the shields installed during your entire tour? 

o If not, how many months during your tour(s) were the shields installed? 

ADDITIONAL COMMENTS 
HQ USCG, CG-1133 (Jul 2011) Page 4 of 4 Pages 

SECTION IV: SIGNATURE 

I certify under penalty of perjury under the laws of the United States of America that the information provided on this form 

is true and correct. 

Signature: _________________________________________________ Date: ______________________________ 

SECTION V: PRIVACY ACT STATEMENT 

AUTHORITY: 38 U.S.C. 1154 (Veterans’ Benefits) delineates United States Coast Guard (USCG) and Department of 

Veterans Affairs (VA) responsibilities for collection of information in the adjudication of non-presumptive radiogenic 

disease compensation. 

PRINCIPAL PURPOSES: The information on this form is necessary to facilitate location of record(s) or information, 

provide participation and dose information, support scientific studies or medical follow-up programs, and provide data or 

documentation relevant to the processing of administrative claims or litigation. For use by Agency officials, employees, 

and authorized contractors. 

ROUTINE USES: Disclosures are permitted under 5 U.S.C. 552a(b) of the Privacy Act, to USCG, VA, Department of 

Homeland Security, Department of Defense, Department of Labor, Veterans’ Advisory Board on Dose Reconstruction and 

under the ‘Blanket Routine Uses’ published at the beginning of USCG’s compilation of systems of records notices. 

DISCLOSURE: Voluntary. However, failure to provide the requested information may delay or preclude the USCG/VA 

from producing your radiation dose assessment. 

SECTION VI: AGENCY DISCLOSURE NOTICE 

The public reporting burden for this collection of information is estimated to be less than one hour. If you have any 

questions regarding this form, please write to: HQ USCG, CG-1133, 2100 Second Street SW, Mail Stop 7902, Washington, 

DC 20593-7902. 
Appendix 2: NIOSH-IREP Website Screen Shots

1st Shot: 

2nd Shot: 
3rd Shot: 

NIOSH-Interactive RadioEpidemiological Program 

Probability of Causation Results

Date of Run: 1/14/2011 NIOSH-IREP version: 5.6

Time of Run: 6:31:11 PM Analytica/ADE version: 3.0

Claimant Name: John Q. Doe

Claimant Cancer Diagnoses:

Primary Cancer #1: Prostate Cancer Date of Diagnosis: 2009 

Claimant Information Used In Probability of Causation Calculation:

Gender: Male Race (skin cancer only): N/A

Birth Year: 1939 Year of Diagnosis: 2009

Cancer Model: All Male Genitalia (185-187) Should alternate cancer model be run?: No

Smoking history (trachea, bronchus, or lung cancer only): N/A 

NIOSH-IREP Assumptions and Settings:

User Defined Uncertainty Distribution: Lognormal(1,1) 

Number of Iterations: 2000 Random Number Seed: 99

General Exposure Information:

# Exp. Year Organ Dose (cSv) Exp. Rate Radiation Type

1 1965 Constant (0.377) acute photons E<30keV 

2 1966 Constant (0.377) acute photons E<30keV 

3 1967 Constant (0.377) acute photons E<30keV 

4 1968 Constant (0.377) acute photons E<30keV 

Probability of Causation (PC)

 1st percentile 0.00 %

 5th percentile 0.00 %

 50th percentile 0.27 %

 95th percentile 2.10 %

 99th percentile 4.08 %
Appendix 3: 38 CFR 3.311b – VA Nonpresumptive Radiogenic Diseases

1. All Leukemias (except CLL) 

2. Thyroid cancer 

3. Breast cancer 

4. Lung cancer 

5. Bone cancer 

6. Liver cancer 

7. Skin cancer 

8. Esophageal cancer 

9. Stomach cancer 

10. Colon cancer 

11. Pancreatic cancer 

12. Kidney cancer 

13. Urinary bladder cancer 

14. Salivary gland cancer 

15. Multiple myeloma 

16. Posterior subcapsular cataracts 

17. Non-malignant thyroid nodular disease 

18. Ovarian cancer 

19. Parathyroid adenoma 

20. Tumors of the brain and CNS 

21. Cancer of the rectum 

22. Lymphomas other than Hodgkin's disease 

23. Prostate cancer 

24. Any other cancer 

A3.1
DISTRIBUTION LIST 

DTRA-TR-10-26 

UNITED STATES COAST GUARD 

COMMANDANT (CG-1133) 

Division of Environmental Health & Industrial Hygiene 

U.S. Coast Guard Headquarters 

1900 Half Street, SW, Jamal Bldg. 

Washington, DC 20593-0001 

COMMANDANT (CG-5532) 

Division of Electronic Navigation 

US Coast Guard Headquarters 

2100 2nd Street SW, Mailstop 7683 

Washington, DC 20593-7683 

Commander, USCG Personnel Service Center 

Attn: CDR Dana Thomas PHS/USCG 

4200 Wilson Boulevard, Suite No. 950 

Arlington, VA 22203 

Commanding Officer 

USCG SECTOR Baltimore Logistics 

Attn: LCDR Jeffrey Hall, USCG 

2401 Hawkins Point Rd 

Baltimore, MD 21226 

DEPARTMENT OF DEFENSE 

Defense Technical Information Center 

Attn: DTIC/OCA 

8725 John J. Kingman Road 

Fort Belvoir, VA 22060-6201 

Defense Threat Reduction Agency 

Attn: Dr. Blake, RD-NTSN 

8725 John J. Kingman Road, 

Fort Belvoir, VA 22060-6201

Defense Threat Reduction Information Analysis Center 

Attn: OP-ONIUI 

8725 John J. Kingman Road 

Fort Belvoir, VA 22060-6201 
Officer in Charge 

Naval Dosimetry Center 

8901 Wisconsin Ave 

Bethesda, MD 20889-5614 

DEPARTMENT OF VETERANS AFFAIRS

Department of Veterans Affairs 

Veterans Health Administration 

Director, Environmental Agents Service (10P3A) 

810 Vermont Ave., NW 

Washington, DC 20420 

Department of Veterans Affairs 

Veterans Benefits Administration 

Director, Compensation Service (211B) 

810 Vermont Ave., NW 

Washington, DC 20420 

Department of Veterans Affairs 

VA Regional Office 

Attn: Director (21 - Radiation) 

1600 East Woodrow Wilson Ave. 

Jackson, MS 39216 

FEDERAL AGENCY ADVISORY BOARDS 

Veterans’ Advisory Board on Dose Reconstruction 

801 North Quincy Street, Suite 600 

Arlington, VA 22203 

Veterans’ Advisory Committee on Environmental Hazards 

Department of Veterans Affairs 

Compensation Service (211) 

810 Vermont Ave., NW 

Washington, DC 20420 

INTERESTED INDIVIDUALS 

ETCM Chuck Severance, USCG (retired) 

PMB 293 Suite A-113 

1830 E. Parks Hwy 

Wasilla, AK 99654