DRAFT

WHITE PAPER FOR GSI APPENDIX BB REVIEW

For Discussion Purposes Only

Background

The NIOSH dose estimate for General Steel Industries (GSI) employees is described in 

Appendix BB to Battelle 6000, approved on June 25, 2007. This dose estimate was 

reviewed by SC&A and documented in a report dated March 17, 2008. The report was 

subsequently reviewed and made available on the OCAS website in April 2008. Neither 

report had the advantage of using film badge data later retrieved from Landauer Inc. This 

white paper describes the film badge data as well as analyzes the film badge results. It 

also identifies several inconsistencies in the SC&A report and the effect of correcting 

them. Lastly, the white paper will examine the effect of the film badge results on these 

corrected values.

Analysis of Film Badge Data

Data

The oldest data received from Landauer covers the week beginning January 1, 1964 (a 

Tuesday). The next oldest data covers the week beginning January 6, 1964 (a Sunday) 

followed by the week beginning January 13, 1964. The data continues to cover every 

week with the last week covered being the week beginning December 10, 1973.

The data provides the last name of the person to which the badge was assigned. It also 

provides the results of the badge processing. An “M” was recorded for readings that 

were less than the recording level of 10 mr. The current reading as well as the 

cumulative dose for the calendar quarter and year was included. The report also included 

a cumulative dose for the individuals’ entire employment at the site. However, it is 

important to realize the beginning of this tabulation is the day that person started wearing 

a film badge, not the day the individual actually began employment. Lastly, the report 

indicates the number of times the person was monitored by film badge and the first week 

he was monitored. The early reports indicate 17 people were monitored beginning on 

November 6, 1963. However, the weekly reports prior to January 1, 1964 were not 

recovered. A spot check of these values indicates several people were often missing from 

the report in late December and would show up again in January. The cumulative 

number of badges was not increased while the names were missing. This likely indicates

vacation time was accounted for in this total. 

A total of one-hundred eight different names were recorded between 1964 and 1973. 

There were never that many names assigned a badge at any one time. Through June 

1966, a total of 6999 badge readings were recorded for individuals. Of these, 22 were 

recorded at or greater than the 10 mr recording level. For the full amount of data, from 

1964 through 1973, a total of 16292 individual badge readings were recorded with a total 

of 49 recorded greater than 10 mr. Also, there were 114 badges recorded as “Betatron 
CTL” for the Betatron Control room. The last was the week of February 6, 1966. All 

114 readings were less than 10 mr.

Representativeness of Data

Individuals that clearly identified themselves as being associated with radiography 

(Radiographer, Radiographer Helper, Film Processor, etc) during worker outreach 

meetings (a total of five people) were checked against the film badge data. The names of 

all five appear in the records. Also, an article from a company publication named 11 

people that had passed a 32-hour course in Health Physics. The article indicated the 

course was to “qualify them as radiographers in handling radioactive isotopes”. All 11 

names were checked against the dosimetry reports and all 11 appear in the records.

With all 17 people known to be associated with radiography included in the records, it 

appears that the all the employees directly associated with radiographers were assigned a 

film badge at GSI between 1964 and 1973. It also appears these radiographers were 

indeed the ones who performed the source radiography. The betatron buildings were 

described as a very busy place. With only 108 names appearing over the entire time 

span, it appears equally clear that ancillary workers (those working to move or repair 

castings, maintenance personnel, etc.) that were not directly involved with the 

radiography were not issued film badges.

The question of how representative these readings are for years prior to 1964 must be 

asked. Only one betatron existed at the site prior to 1963. During 1963, a new betatron 

building was built and a betatron was moved from the Eddystone, PA site to the Granite

City site. The “new betatron” as it was called was reportedly upgraded when it was 

moved to Granite City. Operators indicated that the new betatron had a higher output 

than the old betatron. 

More importantly, a supervisor for the betatrons described work prior to 1963 as much 

slower paced. He indicated prior to 1963 the radiography was essentially a quality 

control function that checked a sampling of castings. In 1963 the role of radiography at 

GSI changed from “two people who worked there part time to, as these guys have said, 

seven days a week, 24 hours a day and we were 500 percent overscheduled”. Another 

worker indicated that 1963 to 1966 was the peak production period. 

It appears after 1963 the radiography at GSI occurred much more often and included a 

higher output machine. This indicates the film badge readings starting in 1964 would not 

necessarily be representative of the pre-1963 dose but it should be higher and thus 

bounding.

Analysis

From 1964 through the end of the contract period (June 1966) only 22 of the 6999 film 

badges processed resulted in a reading greater than 10 mr. With 99.7% of the readings 

being below the recording level, statistical analysis is limited. The rank-file 95th

percentile is obviously less than 10 mr. If a lognormal distribution is assumed, the 

distribution results in a geometric mean of 2.06x10-5 mr/badge reading. The geometric 
standard deviation of this distribution would be 100. This results in a 95th percentile of 

0.04 mr/badge reading. While there is no standard value considered too high for a 

geometric standard deviation, a value of 100 is very high. If a normal distribution is 

assumed, the mean is 0.46 mr/badge reading with a standard deviation of 29.8 mr. This 

results in a 95th percentile of 49.4 mr. Since a normal distribution is symmetrical about 

the mean, this distribution implies 49.3% of the values of this distribution are less than 

zero. Obviously it is impossible for the true radiation dose to be less than zero. While a 

small percent of negative values may still represent a distribution that is an acceptable 

approximation of the true distribution, nearly half the values being negative is clearly not 

a good approximation.

Next, the average badge reading for each individual was determined. The individuals 

were monitored for different periods and lengths of time. Therefore, to normalize the 

values an average weekly reading was determined for each individual. That is, each 

person’s recorded dose was divided by the total number of badges he was assigned. A 

distribution of these averages was then determined. Sixty-seven of the eighty-nine 

individuals (approximately 75%) had no dose recorded at or above the recording level of 

10 mr. The average of these values was 0.371 mr with a standard deviation of 2.76 mr. 

Again, this results in a normal distribution with a large fraction of the values (44.6%) 

being less than zero. If a lognormal distribution is assumed, the geometric mean is 

0.0065 mr with a geometric standard deviation of 16.7. The 95th percentile of this 

distribution would be 0.673 mr. With the high percentage of censored data and a GSD 

that is still relatively high, additional distributions were explored.

From the above description, it is clear that no analysis of this data is going to provide a 

distribution that clearly well represents the data. This is due to the high percentage of 

censored data. As an alternate approach, the recording level (10 mr) was substituted for 

each reading recorded below the recording level. As with the last analysis, a weekly 

average reading for each individual was then determined using these substituted values. 

A distribution of these values has an average of 10.35 mr with a standard deviation of 

2.75 mr. That produces a 95th percentile of 14.87 mr. If a lognormal distribution is 

assumed, the geometric mean is 10.2 mr with a geometric standard deviation of 1.15 for a 

95th percentile of 12.78 mr.

The parameters of both of these distributions are more reasonable than the previouslyreported distributions. The normal distribution does not imply a large fraction of the 

readings have a negative value. The GSD of the lognormal is not exceedingly high and 

the median and 95th percentiles of both distributions are relatively similar. The 

substitution is obviously a bounding substitution (replacing those recorded as less than 10 

mr with 10 mr). It is equally obvious that with 99.7% of the values replaced with this 

substitution that the result is a bounding estimate of the recorded dose. However, in 

order to insure the doses actually recorded are accounted for, the 95th percentile is used. 

This is essentially the upper bound of a bounding distribution. Therefore, the 14.87 mr 

per reading (per week) is used for the rest of this white paper.
Inconsistencies in SC&A review of Appendix BB

Betatron Operator Exposure to Apparatus

In the SC&A review of Appendix BB, photon dose from the betatron apparatus was 

based on two different scenarios. For the “short shot” scenario, the casting was assumed 

to be 9 feet from the betatron target and the betatron operators’ distance from the 

apparatus was assumed to vary uniformly between 3 feet and 6 feet. The operator is 

therefore assumed to be at a distance of 3 feet to 6 feet from the casting. However, the 

photon dose from the casting was based on the assumption that the operator was 1 foot 

from the casting half of the time and 1 meter (approx. 3.3 feet) from the casting the other 

half. Combining these two scenarios effectively puts the operator in two places at one 

time. 

Using the same technique described in the review, the dose from the apparatus can be 

recalculated to be consistent with the other scenarios. That is, the operator is assumed to 

be 1 foot from the casting half of the time (5 feet from the apparatus for long shots, 8 feet 

for short shots). The other half of the time, the operator is assumed to be 1 meter from 

the casting (approximately 2.7 feet from the apparatus for long shots, 5.7 feet for short 

shots)

The formula on page 19 of the SC&A report were used to calculate dose based on a 

uniform varying distance. However, since the exposure scenario elsewhere in the report 

indicates a dose rate from two set distances was used, this formula is not necessary. The 

inverse square law was used to determine the initial exposure rate at the various 

distances. These were based on the exposure rate of 15 mr/hr at 6 feet. The initial 

exposure rates are then 73 mr/hr at 2.7 feet, 16.5 mr/hr at 5.7 feet, 21.6 mr/hr at 5 feet, 15 

mr/hr at 6 feet and 8.44 mr/hr at 8 feet. 

The formula on page 20 was used to determine the dose over the exposure period taking 

into account the decay rate. This formula assumes an operator is exposed from the 

moment the betaton is turned off to the end of the assumed period of time (11 minutes for 

the short shot scenario, 15 minutes for the long shot scenario). However, when the dose 

from the uranium metal and steel after the shot was calculated in the report, it was 

assumed that the operators were not exposed for the first 5 seconds after the shot. This 

was described as the minimum amount of time it would take to exit the control room and 

reach the vicinity of the metal object. In order to allow this same assumption for the 

apparatus dose calculation, the formula on page 20 is adjusted to:



 

 

 

2

1

0 0

60

( )

60

( )

1 2

t

t

t t

t R e e

e dt RX t



 



In this equation, t1 is the time from the end of the x-ray exposure until the operators reach 

the betatron (5 seconds). Also, t2 is the time from the end of the x-ray exposure until the 

operators leave the betatron area (11 minutes for the short shot scenario and 15 minutes 

for the long shot scenario). 

In order to minimize rounding errors, the dose rates in the SC&A document were first 

recreated. Next, the exposure was calculated as described above and the exposure for the
two appropriate distances were averaged. This average was multiplied by the number of 

“shots” described in Table 16 to arrive at the exposure per shift.

Railroad Shot Exposure Scenario

Dose rates outside the new and old betatron building were modeled based on two 

scenarios. One was a “center shot” in which the betatron was in the approximate center 

of the shooting area while an x-ray exposure was occurring. The other was a “railroad 

shot” in which a casting is assumed to be exposed while sitting on a railroad car straight 

in from the equipment door. The betatron has limit switches that prevent a shot from

occurring in this position but operators indicated they were ordered to defeat these limit 

switches by “flipping the head” of the betatron and perform shots in this position. The 

operators went on to indicate that this was not done until the supervisor present in the 

early 1960s left the company and was replaced by another. This supervisor left the 

company on 6/30/1966 which is the last day of the uranium work. This information 

indicates the railroad shots occurred after the covered period. The analysis performed by 

SC&A summarized photon dose rates based on the railroad shot scenario. However, 

some dose rate information for the center shot was included in the report. 

Table 2 shows that the exposure rate in the control room of the new betatron building is 

calculated to be 1.9 mr/hr for the railroad shot and 0.3 mr/hr for the center shot. Likewise 

the neutron dose is calculated to be 0.6 mrem/hr for the railroad shot and 0.3 mrem/hr for 

the center shot. Table 3 provides two exposure rates for the control room of the old 

betatron building. These two values were averaged when calculating values for Table 16. 

The average of the railroad shot photon exposure rate was 1.05 mr/hr. The SC&A report 

provided no values for a center shot, however, values for the center shot can be calculated 

similar to those calculated for the new betatron building. This was done using MCNP to 

find control room values for both neutron and photon doses. The same two points in the 

control room were used. Only the location and orientation of the betatron and the steel 

were changed.

250 R/min Exposure Rate from Old Betatron Machine

SC&A used a betatron output of 250 R/min from both the new and old betatron 

machines. This was based on a letter from a former Allis Chalmers employee. It was 

also noted that this was consistent with a GSI employee recollection of 160 R/min once a 

35% reduction for the beam compensated was factored in. However, the seven tube 

outputs listed by the Allis Chalmers employee represent shipping dates between 

12/29/1969 and 5/31/1973. In the paragraph immediately preceding this table, the 

employee wrote:

Tubes manufactured in the early 1950s produced outputs between 125-150 R/M, 

the 1960s between 200-275 R/M and by the late 1970s, between 300-375 R/M @ 

25 Mv. 

Both betatrons were built in the early 1950s but the new betatron was originally in 

Eddystone, PA. That betatron was moved to GSI in 1963 and reportedly underwent an 
upgrade at that time. The statement above from the Allis Chalmers employee indicates 

the early 1950s model would have an output between 125 and 150 R/min. This is also 

consistent with GSI employee recollections. During an August 21, 2006 meeting, an 

operator indicated the output of the new betatron was between 200 and 250 R/min but the 

old betatron “couldn’t do that good”. He indicated the old betatron had an output of 

“probably 100, 110 at maximum”. The SC&A report relied on the recollection of a GSI 

employee that he recalled 160 R/min on the new betatron. The same employee in a 

meeting held on October 9, 2007 indicated that a 10,000 R shot would have taken 1 hour 

and 15 minutes (133 R/min) but that the old betatron would have taken longer because it 

did not have a capacitor bank.

The compensator used to flatten the photon flux causes a reduction of about 1/3 of the 

beam intensity (35% per the SC&A report). The Allis Chalmers employee was referring 

to the uncompensated output of the betatron. If the maximum 1950s output is assumed 

(150 R/min) the compensated beam would have an output of approximately 100 R/min. 

This is consistent with the GSI employee recollection. Either way, both GSI employees 

clearly remember the output of the old betatron being lower than the output of the new 

betatron. Therefore, the rest of this white paper will consider the uncompensated output 

of the new betatron to be 250 R/min and the uncompensated output of the old betatron to 

be 150 R/min.

Inconsistent Assumption between Photon and Beta dose 

A summary of the annual doses is presented in the SC&A report. Section 2.6.1 describes 

the photon and neutron doses while Table 21 in section 2.6.2 describes the beta doses. In 

order to estimate the beta dose, an estimate of the amount of uranium work was 

performed and a mixture of uranium and steel work was used. However, in order to 

estimate the photon and neutron doses, no uranium work was assumed. This leads to the 

inconsistent assumption that employees were working both with and without uranium at 

the same time. The remainder of this white paper will use the estimated uranium versus 

steel work time used in the beta dose calculation.

The effect of adjusting for these inconsistencies is shown in the next two tables. The first 

table is a recreation of Table 16 from the SC&A report. The second table is the same 

table with the values adjusted as described above. The values in the first table were 

recreated as best as possible from the SC&A report as well as MCNP output files 

provided by SC&A. The recreation produced some differences between this table and 

Table 16 in the SC&A report due primarily to different rounding errors. One value, the 

photon exposure from uranium metal in the new betatron building, was incorrectly 

reported in the original SC&A report as 0.66 mr/shift and later corrected to 6.8 mr/shift. 

However, the recreation below resulted in a value of 6.56 mr/shift. This represents the 

largest difference in attempting to recreate this table. The 6.56 mr/shift was recreated 

starting with values from tables 8 and 9 from the SC&A report. While round-off error 

may explain some of the difference, it can not explain it all. 
Recreation of Table 16 from SC&A review of Appendix BB

Metal Type of shot Number 

per shift

Fraction Source of 

radiation

Duration 

(h/shift)

Exposure 

(mR/shift)

Neutron dose 

(mrem/shift)

25 MeV

HY-80

Short 32 64%

Control room 1.6 3.11 0.92

Metal 5.87 0.35

Doughnut 5.87 34.56

Total 38.02 0.92

Long 6 36%

Control room 6.0 11.66 3.44

Metal 1.5 0.66

Doughnut 1.5 13.03

Total 25.35 3.44

Composite 100% 33.46 1.82

Uranium Long 6

Control room 6.0 11.66 3.44

Metal 1.5 6.56 0.67

Doughnut 1.5 13.03

Total 31.25 4.11

24 MeV

HY-80

Short 32 64%

Control room 1.6 1.68 0.59

Metal 5.87 0.35

Doughnut 5.87 34.56

Total 36.58 0.59

Long 6 36%

Control room 6.0 6.29 2.20

Metal 1.5 0.66

Doughnut 1.5 13.03

Total 19.97 2.20

Composite 100% 30.60 1.17

Uranium Long 6

Control room 6.0 6.29 2.20

Metal 1.5 6.56 0.67

Doughnut 1.5 13.03

Total 25.88 2.87
Adjusted Table 16 from SC&A review of Appendix BB

Metal Type of shot Number 

per shift

Fraction Source of 

radiation

Duration 

(h/shift)

Exposure 

(mR/shift)

Neutron dose 

(mrem/shift)

25 MeV

HY-80

Short 32 64%

Control room 1.6 0.50 0.52

Metal 5.87 0.35

Doughnut 5.87 14.37

Total 15.21 0.52

Long 6 36%

Control room 6.0 1.86 1.96

Metal 1.5 0.66

Doughnut 1.5 10.28

Total 12.79 1.96

Composite 100% 14.34 1.04

Uranium Long 6

Control room 6.0 1.86 1.96

Metal 1.5 6.56 0.67

Doughnut 1.5 10.28

Total 18.70 2.63

24 MeV

HY-80

Short 32 64%

Control room 1.6 0.07 0.22

Metal 5.87 0.21

Doughnut 5.87 8.62

Total 8.90 0.22

Long 6 36%

Control room 6.0 0.27 0.84

Metal 1.5 0.39

Doughnut 1.5 6.17

Total 6.83 0.84

Composite 100% 8.16 0.45

Uranium Long 6

Control room 6.0 0.27 0.84

Metal 1.5 4.08 0.40

Doughnut 1.5 6.17

Total 10.52 1.24
Application of Film Badge Data

With an analysis of the film badge data and the adjustments to the SC&A model in place, 

it is possible to put the information together. A briefing of the model was previously 

given to a working group of the Advisory Board by SC&A. An overview of the dose was 

provided in a table format during that briefing. The table is a recreated below.

Estimated Annual External Exposures of Betatron Operators

Years

External exposure

(R/y)

Neutron dose 

(mrem/y)

Skin dose (rads/y)

Hand & forearms Other skin

SC&A NIOSH SC&AaSC&A NIOSH SC&A NIOSH

1952-

1957b 12.4 5.8 470 27.2 19.4 2.5 1.8

1958 12.4 5.8 470 25.9 19.4 2.4 1.8

1959-1960 12.4 5.8 470 24.7 19.4 2.4 1.8

1961 12.4 6.3 470 28.1 22.3 2.6 2.0

1962 12.4 5.1 470 20.9 16.2 2.2 1.65

1963 12.4 2.8 470 7.0 4.4 1.4 0.4

1964 13.6 2.2 735 3.8 1.6 1.2 0.15

1965 13.6 2.1 735 3.3 1.2 1.2 0.11

1966c6.8 1.0 368 1.4 0.37 0.6 0.034

a Neutron doses not assessed by NIOSH

b NIOSH assumed covered period began 1953

c

Total during covered period: January 1 – June 30

The photon dose of 14.87 mr/week from the film badge data can be multiplied by a 50 

week work year resulting in an annual exposure of 743.6 mr/yr. The values in the table 

above were recreated and then adjusted for the inconsistencies described earlier. After 

that, a value of 743.6 mr/yr was substituted for the photon exposure and the neutron and 

skin dose was adjusted proportionately. The resulting dose is shown in the table below.

Adjusted Annual External Exposures of Betatron Operators

Years External exposure

(R/y)

Neutron dose 

(mrem/y)

Skin dose (rads/y)

Hand & forearms Other skin

1952-1957 0.7436 41 6.733 0.536

1958 0.7436 41 6.369 0.514

1959-1960 0.7436 41 6.009 0.493

1961 0.7436 41 0.550 6.978

1962 0.7436 41 0.431 4.959

1963 0.7436 41 0.224 1.450

1964 0.7436 41 0.160 0.485

1965 0.7436 54 0.156 0.418

1966 0.3718 54 0.076 0.175