ORAU Team

Dose Reconstruction Project for NIOSH

An Exposure Matrix for Superior Steel, Carnegie, Pennsylvania, 

Period of Operation: January 1, 1952 through December 31, 1957

Document Number:

ORAUT-TKBS-0034

Effective Date: 08/09/2005

Revision No.: 00 PC-1 

Controlled Copy No.: ______

Page 1 of 23

Subject Expert: Shelby L. Gubin

Document Owner

Approval: Signature on File Date: 04/25/2005

Cindy W. Bloom, TBD Team Leader

Approval: Signature on File Date: 04/27/2005

Judson L. Kenoyer, Task 3 Manager

Concurrence: Signature on File Date: 04/28/2005

Richard E. Toohey, Project Director

Approval: Signature on File Date: 05/03/2005

James W. Neton, Associate Director for Science

Supersedes:

None

TABLE OF CONTENTS

Section

Record of Issue/Revisions ...................................................................................................................

Page

4

Acronyms and Abbreviations ...............................................................................................................5

1.0 Introduction................................................................................................................................. 6

2.0 Site Description and Operational History.....................................................................................6

2.1 Site Description.....................................................................................................................7

2.2 Process Description ..............................................................................................................8

2.3 Source Term .........................................................................................................................9

2.4 Safety..................................................................................................................................10

2.4.1 Workplace Contamination Controls .....................................................................................10

2.4.2 Air Concentrations...............................................................................................................10

2.4.3 Contamination/Radiation.....................................................................................................11

2.5 Incidents..............................................................................................................................11

2.6 Physical Examinations – X-rays ..........................................................................................11

2.7 Summary Operational Period Assumptions, Workdays, Work Hours, Work Categories....... 11

2.8 Cleanup/Residual Contamination Period.............................................................................12

3.0 Estimation of Internal Exposure ................................................................................................ 12

3.1 Uranium ..............................................................................................................................12

3.1.1 Uranium Air Sampling .........................................................................................................12

3.1.2 Enriched and Recycled Uranium .........................................................................................15

3.2 Occupational Internal Dose Reconstruction Assumptions and Summary............................. 16

4.0 Estimation of External Exposure ............................................................................................... 16
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4.1 Submersion and Contamination Exposures.........................................................................17

4.2 Slabs and Plates Exposures................................................................................................17

4.3 Occupationally Required Medical X-Ray .............................................................................18

4.4 Miscellaneous Information Related to External Dose ..........................................................18

4.5 Occupational External Dose Reconstruction Assumptions and Summary ........................... 19

5.0 Estimation of Residual Exposure .............................................................................................. 19

References ........................................................................................................................................22
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LIST OF TABLES

Table

1 Air concentrations ..................................................................................................................

Page

13

2 Internal exposures during rolling operations........................................................................... 14

3 Inhalation exposure during non-AEC operations due to resuspension of 

deposited uranium dust.......................................................................................................... 15

4 Estimated amount of uranium ingested (based on Tables 1 and 2)........................................ 15

5 Estimate of contaminant activity fractions in a recycled uranium source term......................... 15

6 Internal exposure summary for operational period January 1, 1952, to 

December 31, 1957................................................................................................................16

7 Calculated dose rate for uranium slabs and uranium plates ................................................... 17

8 Direct radiation measurements from September 1948 ........................................................... 18

9 External exposure summary for operational period January 1, 1952, to 

December 31, 1957................................................................................................................19

10 Superior Steel measured radiation levels on July 31, 1980 .................................................... 20

11 Annual internal and external exposure to residual radioactivity .............................................. 21

LIST OF FIGURES

Figure

1 Superior Steel processing areas ..............................................................................................

Page

7

2 Superior Steel uranium mill layout............................................................................................8
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RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE REV. NO. DESCRIPTION

Draft 12/28/2004 00-A New Technical Basis Document: Basis for the 

Development of an Exposure Matrix for 

Superior Steel, Carnegie, Pennsylvania. 

Initiated by Shelby L. Gubin.

Draft 12/29/2004 00-B Modified to address ORAU Team review 

comments: corrected errors and clarified text. 

Initiated by Cindy W. Bloom.

Draft 02/15/2005 00-C Modified to address OCAS comments and 

typographical errors. Nonpenetrating doses 

were modified. Some annual doses in Tables 

9 and 11 were modified. Initiated by Cindy W. 

Bloom.

Draft 02/25/2005 00-D Modified to address OCAS comment. The 

DOE Office of Worker Advocacy website 

changed their description of Superior Steel 

activities. Initiated by Shelby L. Gubin. 

Draft 04/21/2005 00-E Modified intakes based on assuming 95th

percentile of air concentrations per OCAS. 

Initiated by Cindy W. Bloom.

Draft 04/22/2005 00-F Deleted last 3 rows (GMs and GSDs) of Table 

1 to eliminate confusion per OCAS. Initiated 

by Cindy W. Bloom.

05/03/2005 05/03/2005 00 First approved issue. Initiated by Cindy W. 

Bloom.

05/03/2005 08/09/2005 00 PC-1 Corrected 4 listed dose rates in Table 9 on 

page 19. Annual doses are unchanged. 

Training required: As determined by the Task 

Manager. Initiated by Cindy W. Bloom. 

Approval:

Cindy W. Bloom, TBD Team Leader

Signature on File_____________06/22/2005

Judson L. Kenoyer, Task 3 Manager

Signature on File_____________06/22/2005

Richard E. Toohey, Project Director

Signature on File_____________06/22/2005

James W. Neton, Associate Director for Science

Signature on File_____________08/09/2005
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ACRONYMS AND ABBREVIATIONS

AEC U.S. Atomic Energy Commission

BZ breathing zone

cm centimeter

dpm disintegrations per minute (also d/m)

ft foot

FUSRAP Formerly Utilized Sites Remedial Action Program

GA general area

GSD geometric standard deviation

h hour

ICRP International Commission on Radiological Protection

in. inch

IREP Interactive RadioEpidemiological Program

keV kilovolt-electron

L liter

m meter

mg milligram

mR milliroentgen

mrem millirem

mrep millirep

NYOO New York Operations Office

pCi picocuries

R roentgen

s second

U.S.C. United States Code

y year

μg microgram

μm micrometer
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1.0

Technical Basis Documents and Site Profile Documents are general working documents that provide 

guidance concerning the preparation of dose reconstructions at particular sites or categories of sites. 

They will be revised in the event additional relevant information is obtained about the affected site(s). 

These documents may be used to assist the National Institute for Occupational Safety and Health 

(NIOSH) in the completion of the individual work required for each dose reconstruction.

INTRODUCTION

In this document, the word “facility” is used as a general term for an area, building or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act of 2000 [42 U.S.C. Sections 7384l (5) and (12)]. 

This document provides an exposure matrix for workers at the facility listed as Superior Steel 

Corporation in Carnegie, Pennsylvania. At the time of U.S. Atomic Energy Commission (AEC) 

contract operations, the company was known as Superior Steel Corporation. Later it was known as 

Copper Weld Inc. and as Lot and Block 102J210. Other names associated with the site are Lange 

Machinery Company, Inc.; J.G. Industries, Inc.; Carnegie Industrial Park, and Superior Tube 

Company (ORNL 1981, Young 1985). The site was reportedly located at the intersection of 

Hammond and Superior Streets and/or Hammond and Gregg Streets (Young 1985). 

2.0

The information that follows supports an assumed period of AEC operations at Superior Steel from 

January 1, 1952, through December 31, 1957, involving AEC-contracted uranium work. This analysis 

assumed that the residual contamination period was from January 1, 1958 through the present. 

SITE DESCRIPTION AND OPERATIONAL HISTORY

The Superior Steel radiological source term consisted primarily of natural uranium metal, uranium 

oxides, and natural uranium’s short-lived progeny. Long-lived progeny in the uranium series prevent 

significant ingrowth past 234U in the 238U decay series and beyond 231Th in the 235U decay series. 

Letter Contract AT(30-1) -1412 (a unit price contract) was awarded to Superior Steel in June 1952, 

because it was one of the few companies that had the technical expertise to roll and clad metal strip 

and plate (Young 1985). The effective date of the contract was June 27, 1952. According to Young 

(1985), AEC security inspection records indicate that work began in March 1953, although it was also 

noted that Superior Steel was an accountable station for handling source and fissionable materials by 

November 1952. It wasn’t unusual for AEC work to start at a site several months before a contract 

was official, so this analysis assumes that the work began on January 1, 1952.

The original Superior Steel contract is unavailable, but a contract was also awarded to Metals & 

Controls for similar work and it was assumed that the same boilerplate contract articles were included

(Young 1985, AEC 1952). The contract originated from the AEC New York Operations Office. The 

contract was transferred for administration to the Oak Ridge Operations Office and on October 15, 

1954 was transferred to the Savannah River Operations Office. According to the Savannah River 

Operations Office, Superior Steel contract files have been destroyed. However, correspondence files 

relating to the work done by Superior Steel indicate they rolled, cut and finished uranium metal into 

strip under a cost plus fixed fee contract (Young 1985). The contract was terminated on or about 

September 30, 1957 (Young 1985). The withdrawal of Superior Steel’s source and fission material 

accounting station authority was recorded on November 27, 1957 (Young 1985). This analysis 

assumes that the AEC operations ceased on December 31, 1957
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2.1 SITE DESCRIPTION

ORNL (1981) reports that the Superior Steel uranium operations occurred in a large steel building that 

was divided into three areas. These areas (ORNL 1981) are shown in Figure 1: 

The former mill area (Area A), the former motor room (Area B), and the former rolling area 

(Area C). 

Area A (... approximately 24,000 ft.2) originally contained the salt bath, roughing mill, brushing 

station, finishing stands and shear, and was the location where the majority of the uranium 

metal handling and shaping is believed to have occurred ...

Area B housed the former motor room and control panels for the mill. This area (approximately 

8250 ft.2) contained the large motors that provided power to the mill equipment in the adjacent 

room (area A). This area was considered the “clean” side of the mill, where the atmosphere 

was controlled to provide proper conditions for motor and instrument operation... 

Area C (...approximately 12,000 ft.2) was originally the location of the tail end of the mill 

process where the metal was rolled for shipping, or prior to further handling. Two pits at the 

south end of the building ... indicate the prior locations of the bliss downcoiler [a machine to 

coil the metal] and upender [a tool to tilt a roll of material 90 degrees].

Figure 1. Superior Steel processing areas (ORNL 1981). 

Figure 2. shows the line as operated at Superior Steel.
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Figure 2. Superior Steel uranium mill layout (ORNL 1981). 

2.2 PROCESS DESCRIPTION 

In 1952, there was interest and demand for flat, plate type reactor fuel elements, because it was 

determined that this geometry provided greater surface-to volume ratio than cylindrical fuel leading to 

more efficient use of uranium in reactors.

The process at Superior Steel is as follows (AEC 1953a, 1953b, 1995a):

1. A 1” thick slab of uranium any where from 61” to 89” long and from 5.5” to 7” wide was 

placed into a rectangular steel vessel containing the salt bath (50% LiCl and 50% KCl by 

volume).

2. The salt bath was heated in a gas-fired furnace to a working temperature of around 1200 oF 

for about 45 minutes and then removed from the furnace. In 1953, a new furnace was 

installed that included a salt bath, which eliminated removal of the salt bath from the furnace to 

remove the uranium slab for rolling.

3. The slab was moved by overhead crane to the rolling mill table.

4. The slab was passed through a roughing roll 5 times and sent through the finishing stands, 

(there were 5 finishing stands, but they were not all operational during two of the four AEC 

visits.).

5. The strip was then cut if desired, and transferred with tongs by 10 mill hands to a cooling 

area.

Final thicknesses were between 182 and 191 mils. (E. I. du Pont de Nemours 1954)

Young (1985) notes:

According to general correspondence, work done by Superior Steel was of a developmental 

nature. This work was limited to the production of flat plates of uranium metal in support of the 

Savannah River Operations Office fuel element development program... The scope of the 

contract provided by the Savannah River Operations Office is quoted in part as follows:

“...by commercial methods receive uranium from supplier, inspect, straighten as 

required, scalp by milling, planning [sic] and/or spot grinding, preheat in molten salt, hot 
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roll (taking required temperature and time data), crop and shear to length, number, acid 

pickle (including packing for shipment to heat treating facility and receiving heat treated 

strip), flatten acid pickle, machine into full length strips of specified dimensions and 

tolerances, deburr, gauge finish inspect, metallurgically sample (but not in excess of 

reasonably commercial sampling methods and not including metallurgical tests), 

package and prepare finished plate and furnish labor for packaging and preparing 

scrap for shipment.” 

In 1954, Superior Steel proposed an increase in contractual requirements, calling for minimum 

production quantities over a 5-year period. AEC rejected the proposal and the work continued on a 

developmental basis. Superior Steel processed AEC uranium intermittently for periods lasting from 

one to two days. One AEC employee recalled that most of the work was done on weekends when the 

plant would otherwise be idle, but other documents, including the AEC (1953 a, b; 1955 a, b) air

monitoring studies during uranium rolling, indicated that Superior Steel rolled on weekdays (Young 

1985).

2.3 SOURCE TERM 

Little information was found regarding the Superior Steel source term. AEC performed security 

inspections at Superior Steel on “May and November 1954 and 1955, in June 1956 and in January

1957” according to Young (1985), indicating that there was something to inspect on these dates. The 

DOE (2005) Office of Worker Advocacy website reported, “Superior Steel produced uranium strip and 

rolled uranium slabs for use by the Savannah River Laboratory. In 1955, for example, they hot rolled 

twenty-five tons of uranium into strip.” AEC (1953a, b, 1955a, b) health and safety reports show four 

rolling dates, May 13, 1953, August 3, 1953, May 9, 1955, and September 19, 1955. The last three of 

the reports mention the number of uranium slabs rolled, 23, 30 and 30, respectively. AEC reported 

that six of the slabs rolled on May 9, 1955 were enriched uranium. E. I. duPont de Nemours & Co. 

(1954) reported, “a second rolling of uranium slabs to flat strips” after an initial rolling on August 3, 

1953. On February 22 and 23, 1954, fifty-two slabs were rolled. Thirty-one of the rolled slabs were 

sheared on March 3, 1954. The reference to an initial rolling on August 3, 1953, appears to be a 

reference to a type of rolling, not the initial uranium rolling at Superior Steel.

Based on the limited information regarding source term and throughput, this document assumed that 

Superior Steel rolled uranium 8 hours per day, 2 days per week, 50 weeks per year, which is 800 

hours per year. 

The contract information was also considered to provide increased confidence that the assumed AEC 

uranium work-hours are reasonable, although probably overestimated. The total amount paid to 

Superior Steel by AEC through fiscal year 1957 was $356,849 (Young 1985). The contract was a unit 

price contract. An AEC (1949a) contract with Vulcan Crucible (later known as Aliquippa Forge) to do 

uranium rolling work listed a rate of $132 per mill-hour in 1949. Although rates might have differed 

between contractors and throughout the years, this value provides a way to determine a rough 

estimate of Superior Steel’s mill hours by dividing the amount paid by the mill hour rate. This gives a 

total of 2700 hours or about 450 hours per year. Because additional payment may have been due 

Superior Steel and because the actual Superior Steel mill-hour rate is unknown, the 450 hours per 

year is only used to give some credibility to the assumption of 800 hours per year.
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2.4 SAFETY 

Young (1985) reports, “there are no indications of AEC responsibility or involvement in monitoring the 

personal health of workers at the Superior Steel facility where uranium metal was processed.” 

However, four AEC health and safety visits to the mill during uranium operations are documented 

(AEC 1953a, b 1955a, b). 

AEC personnel recorded visits to Superior Steel dated May 13, 1953, August 3, 1953, May 9, 1955 

and September 19, 1955, which resulted in a number of recommendations to improve the safety of 

the uranium rolling operation. As of the third visit, none of these recommendations had been 

implemented. By the fourth visit, some safety recommendations had been implemented, but the 

process had been modified and introduced additional contamination.

2.4.1

In health and safety reports, AEC recommended ensuring the salt coating remained on the uranium or 

providing ventilation over the rolls. Additionally the rolling mill table and conveyor and shear table 

were to be vacuumed after each break in the rolling cycle. Gloves were recommended for rolling mill 

personnel and were to be burned after use and disposed of with uranium oxide scrap stored in drums. 

Face shields were recommended for workers tending the salt bath or loading slabs on the conveyor. 

AEC also pointed out that workers should be informed of the health and safety precautions necessary 

in handling uranium. 

Workplace Contamination Controls 

2.4.2

During World War II, permissible levels for uranium dust in air were set at 500 μg/m3 for insoluble 

uranium compounds and 150 μg/m3 for soluble uranium compounds. After the war, the University of 

Rochester lowered their recommendation for soluble uranium compounds to 50 μg/m3 based on the 

chemical toxicity, which is equivalent to 70 dpm/m3 for natural uranium. This level was based 

primarily on animal studies. The Medical Division of the AEC New York Operations Office (NYOO) 

felt that a “maximum permissible level” was unknown and should be based on human data. 

Therefore, the 50 μg/m3 level was referred to as the “preferred level” (AEC 1949c). Some of the 

Superior Steel reports refer to a maximum allowable concentration (MAC) of 100 dpm/m3

. 

Air Concentrations 

There were four documented visits to Superior Steel during operations by the AEC (1953a, b, 

1955a,b). All the visits reported airborne contamination in excess of recommended levels. The results 

were mixed with either most of the recommendations not being incorporated or proving to be 

ineffective.

AEC noted a lack of ventilation over the rolls in May and August 1953 and May 1955 (AEC 1953a, b; 

1955a), evidenced in part by the dust clouds observed around the roughing roll area. AEC 

recommended that ventilation be added over the rolls and over the shears. Dripping water on the hot 

rolls contributed to the airborne uranium concentrations, and this was to be avoided. 

A furnace that included a salt bath was added prior to the August 1953 AEC survey. A pneumatic cutoff device attached to a “fork-lift type conveyance” replaced the conventional shear as of August 1953 

(AEC 1953b). AEC (1953b) also noted that “two large vacuum cleaning units” were made available to 

Superior Steel for the duration of the contract. As of September 19, 1955, local exhaust ventilation 

was provided at the roughing roll, but a new dust source was introduced. 
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Man-cooling fans were used to reduce air concentrations during the May 1955 processing. Although 

these did appear to reduce concentrations in the process areas, it is likely they caused further spread 

of contamination (1955a). 

By November 1955, ventilation was added over the roughing mill and the shear station. This 

reduction of air concentrations was offset by the set up of a brushing station to remove the salt 

coating on the uranium, which was thought to cause pitting. The brushing caused increased air 

concentrations, as did the lack of a salt coating on the uranium when it went through the rolling 

stands. Clouds of dust were also noted during stamping (AEC 1955b). 

2.4.3

Documentation of contamination and radiation levels at Superior Steel during the AEC operations 

period included the following: 

Contamination/Radiation 

Alpha contamination, greater than 50,000 dpm/100 cm2, was found in many locations after the 

September 19, 1955 uranium rolling. It was noted that a thorough hosing with water reduced 

the contamination to negligible levels (AEC 1955b). Smears taken on the floor and in the area 

near the shears ranged from 175 to 11,400 dpm/150 cm2 of alpha (1953a). (Smear results are 

usually reported for areas of 100 cm2

, but these results were reported for areas of 150 cm2.)

No measurements of ambient radiation levels during AEC operations have been found for Superior 

Steel. Radiation and contamination measured after operations are summarized in Section 5.

2.5 INCIDENTS 

No radiological incidents were noted in the available documentation regarding Superior Steel. 

However, AEC (1953b) noted that Superior Steel mill hands sat on the pile or uranium strips in the 

storage area.

2.6 PHYSICAL EXAMINATIONS – X-RAYS 

No information regarding AEC-required physical examinations for Superior Steel employees has been 

located. 

2.7 SUMMARY OPERATIONAL PERIOD ASSUMPTIONS, WORKDAYS, WORK HOURS, 

WORK CATEGORIES 

It was assumed that employees worked 8 hours per day for 50 weeks per year, for a total of 2000 

hours per year. It was assumed that 100 workdays per year, i.e., 800 work-hours per year, were 

spent rolling uranium. 

No information regarding site access or work categories is available for Superior Steel. Exposure 

assignments are based on data that are suggestive of workers’ exposures and further modified by 

uncertainty parameters, when appropriate, to ensure that the reconstructed dose distributions capture 

the larger exposures. No attempt has been made to sort workers into exposure categories. 

Depending on the organ of interest and the ancillary data associated with a specific claim, additional 

considerations might be appropriate
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2.8 CLEANUP/RESIDUAL CONTAMINATION PERIOD 

Young (1985) reported that no documents indicated that a final cleanup and survey of the site were 

performed as part of the contract close-out process in 1957. 

The Formerly Utilized Sites Remedial Action Program (FUSRAP) began in 1976. ORNL (1981) 

performed a radiological survey on July 31, 1980 to characterize the property for FUSRAP. At the 

time of the survey, the site was being used to rebuild coke oven doors.

Some contamination (the thatched areas in Figure 1) was identified, primarily near the pits located in 

Areas A and C and near a storage shed. A buildup of coke dust from the “current” operation and the 

limited access to areas prevented a rigorous survey (ORNL 1981). Some equipment used during 

AEC work was still present in 1980. No further information regarding the status of the site since 1985

has been located. It is assumed that the site remains accessible, although Superior Steel is no longer 

associated with the site.

3.0

The primary source of internal radiation exposure at Superior Steel was uranium dust produced from 

the manipulation and oxidation of uranium metal during rolling and related processes. Natural and 

enriched uranium were rolled at Superior Steel. It’s also possible that Superior Steel rolled recycled 

uranium after 1952.

ESTIMATION OF INTERNAL EXPOSURE

3.1 URANIUM 

Human and animal studies have indicated that oxides of uranium can be very insoluble (ICRP 1995), 

indicating absorption type S (0.1% and 99.9% with clearance half-times on the order of 10 minutes 

and 7000 days, respectively). Other in vitro dissolution studies of compounds found at uranium 

facilities have shown that oxides of uranium exhibit moderate solubility (Eidson 1994; Heffernan et al. 

2001) suggesting absorption type M (10% and 90% with clearance half-times on the order of 10 

minutes and 140 days, respectively). In vitro dissolution tests on oxides produced from uranium metal 

during depleted uranium armor penetrator tests have indicated multicomponent dissolution rates, with 

25% of uranium dissolving with a half-time of less than or equal to 0.14 days and 75% dissolving with 

a half-time of 180 days. Because there was no specific information on the solubility of aerosols 

produced during operations, this analysis assumed that both types M and S were available. The 

selection of absorption type should depend on the organ of interest.

Individual uranium urinalysis data are unavailable for Superior Steel workers and none are known to 

exist. This document analyzes air monitoring data for use in reconstructing internal doses. 

3.1.1

Air sampling was performed at Superior Steel during some of the uranium rolling (AEC 1953a, b; 1955 

a, b). The air samples consisted of collection on filters of radioactive particulate from breathing zones 

(BZs), and general areas (GAs) during processing. The alpha activity measured on the filter was 

used to determine airborne alpha activity concentrations. When multiple samples at a location were 

collected, AEC used the mean air concentration in subsequent calculations. At most facilities, the 

AEC matched air concentration determinations with information about worker categories, locations, 

tasks, and workers’ time at each location or task; however, AEC noted that this was not feasible at 

Superior Steel (Harris 1953), but did not include the reasoning for this conclusion. 

Uranium Air Sampling
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Four AEC reports of measured uranium air concentrations have been found for Superior Steel. Not all 

locations were measured each time. Although it is likely that workers at one steel mill would have 

similar duties as at another steel mill, it was not considered expedient to try to determine timeweighted exposures for Superior Steel workers. In addition, changes in the process and the safety 

controls resulted in both increased and decreased exposure for any given period. In this document, 

an estimate of intake was made by estimating the 95th percentile of the average air concentrations, 

summarized in AEC 1955b. This was done by sorting and ranking the dated results in Table 1, 

calculating the z-score of each rank, log transforming the air concentrations, plotting the z-scores 

versus the natural logarithms of the air concentrations and fitting a line to this data. The y-intercept of 

the line raised to e was assumed to be the 50th percentile air concentration and the slope of the line 

raised to e was assumed to be the geometric standard deviation, GSD. The line fit was satisfactory 

(the fit parameter, R2 equaled 0.9884: a value greater than 0.9 indicates a reasonable fit). The 95th

percentile air concentration was determined by multiplying the GSD, 5.63, raised to the 1.645 power, 

by the 50th percentile result, 597 dpm/m3. The calculated 95th percentile air concentration is 10250 

dpm/m3. This air concentration was used to estimate workers’ internal exposures. It should be noted 

that although some concentrations reported for Superior Steel are fairly large, these are not outside 

the range of concentrations measured at other steel mills doing AEC work, such as Aliquippa Forge, 

Bethlehem Steel, and Simonds Saw and Steel. Based on the time and motion studies at other AECcontracted steel mills, there is no reason to believe that any one worker would be exposed 

consistently to only large or small air concentrations for extended periods during uranium processing. 

The calculated 95th percentile air concentration was used to calculate upper estimates of internal 

exposures. 

Table1. Air concentrationsa

 

Sample Type Location and Description Alpha dpm/m3

13-May-53 3-Aug-53 9-May-55 19-Sep-55 Maximum

Process Air Vicinity of Salt Bath - 250 42 187 250

Process Air West of Mill runout table 29 861 44 - 861

Process Air East of Mill runout table 39 1514 78 42 1514

Process Air Southwest of Roughing Roll (15 ft away) 2350 1254 - - 2350

Process Air Roughing roll Feed 1280 38520 330 325 38520

Process Air Roughing roll Discharge 2150 1660 336 195 2150

Process Air Northeast of roughing roll (15 ft away) 1400 98 - 243 1400

Process Air West of flying shear 11 - - - 11

Process Air West of brushing station - - - 2680 2680

Process Air At brushing station - - - 553 553

Process Air Northwest of finishing stand #1 310 - - 360 360

Process Air Between Finishing stands 1 and 2 - - - 797 797

Process Air Between Finishing stands 2 and 3 660 150 - - 660

Process Air Between Finishing stands 3 and 4 375 1263 212 564 1263

Process Air Between Finishing stands 4 and 5 7200 262 121 480 7200

Process Air East of Finishing stand 5 (shear) 7600 1950 86 900 7600

Process Air Northwest of shear - - 954 1743 1743

Process Air Northeast of shear - - - 1840 1840

General Area Discharge end of stamping table - - - 1768 1768

Breathing 

Zone Cutting 1 plate into 3 sections at shear - - 9490 - 9490

Breathing 

Zone Stamping 3 sections of plate - - 20170 8950 20170

Breathing 

Zone

Handling plate and tossing scrap into 

drum - - 2044 2257 2257

a. Data From AEC 1955b.
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This analysis of intakes assumes that uranium processing took place between January 1, 1952, and 

December 31, 1957. This analysis also assumed that 100 days of every year were spent rolling 

uranium. It was assumed that uranium processing occurred in 8-hour shifts, although two of the four 

AEC air sampling reports indicate that processing took less than 6 hours. 

The breathing rate is based on the default for light work shown in ICRP Publication 66 (ICRP 1994, 

Table 6, p. 23). The intakes, in pCi, were calculated by dividing the 95th percentile of the air 

concentration, 10,250 dpm/m3

, by 2.22 dpm/pCi and multiplying this result by the breathing rate and 

the assumed number of hours exposed at the given concentration. Superior Steel organ doses from 

internal exposure are assumed to be a constant distribution. Several assumptions included in the 

intake/dose reconstruction are likely to be overestimating assumptions.

Tables 2 lists the estimated inhalation intake during AEC uranium processing work. 

Table 2. Inhalation exposures during rolling operations. 

Work period

Number of 

years

Number of 

potential AEC 

work-hours per 

year

Air concentration 

(pCi/m3)

Breathing 

rate (m3/h) Intake (pCi)

1/1/1952-12/31/1957 6 800 4.62E+03 1.2 2.66E+07

There was a potential for internal exposure to resuspended material from the AEC work during 

non-AEC operations. To estimate exposure from resuspended materials, this analysis assumed that 

surfaces in the building became contaminated by deposition of uranium dust during rolling operations. 

The level of contamination was determined by multiplying the air concentration, listed in Table 2, by 

the indoor deposition velocity and the assumed deposition time. The indoor deposition velocity is 

dependent on the physical properties of the room (such as air viscosity and density, turbulence, 

thermal gradients, and surface geometry). It is also dependent on the physical properties of the 

aerosol particles (such as diameter, shape, and density). In this case, these characteristics are not 

known, so the terminal settling velocity was calculated for an aerosol with the ICRP Publication 66 

default particle size distribution of 5-μm activity median aerodynamic diameter (ICRP 1994a). The 

calculated terminal settling velocity was 0.00075 m/s, which is within the range of deposition velocities 

(2.7 × 10-6 to 2.7 × 10-3 m/s) measured in various studies (NRC 2002a).

The calculated surface contamination level created from airborne dusts during the uranium rolling 

from January 1, 1952, to December 31, 1957, was 5.98E+07 pCi/m2

 (1,330,000 dpm/100 cm2). The 

claimant-favorable assumption was made that all of the surface contamination was present for the 

entire period of AEC operations. Thus, using a resuspension factor of 1 × 10-6/m (NRC 2002b), the 

air concentration due to resuspension would have been 59.8 pCi/m3

. Table 3 lists the assumed 

annual inhalation intake received from resuspension of deposited material. The intake listed in Table 

3 is added to the intake listed in Table 2 before calculation of annual organ dose: the intakes are 

adjusted to intakes per calendar day and summed in Table 6. 
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 15 of 23

Table 3. Inhalation exposure during non-AEC operations due to resuspension of deposited uranium 

dust. 

Work period

Number 

of years

Number of 

potential 

nonAEC workhours per year

Breathing 

rate (m3/h)

Resuspended air 

concentration (pCi/m3) Intake (pCi)

1/1/1952-12/31/1957 6 1200 1.2 59.8 5.17E+05

In the case where inhalation intakes are calculated from air concentrations, ingestion intakes are also 

to be considered. NIOSH (2004) states that the daily ingestion rate in picocuries can be estimated by 

multiplying the daily air concentration in picocuries per cubic meter by a factor of 0.2 for an 8-hour 

workday. The daily ingestion intake rate from rolling operation is estimated from the air concentration 

in Table 2. The daily ingestion intake from resuspended uranium is estimated from Table 3. The 

ingestion intake rates are multiplied by the number of work-hours exposed at the calculated levels and 

summed. Ingestion intakes per calendar day are calculated and shown in Table 4. 

Table 4. Estimated amount of uranium ingested (pCi) (based on Tables 2 and 3). 

Work period

Days of 

uranium 

rolling

Uranium ingestion 

rate (during uranium 

rolling) pCi/d

Days of 

Nonuranium 

rolling 

Uranium ingestion 

rate (during normal 

operation) pCi/d Intake pCi

1/1/1952-12/31/1957 600 923 900 12.0 5.65E+5

3.1.2

Records for Superior Steel indicate natural and enriched uranium were processed. There was no 

mention of depleted uranium. Because the Superior Steel air samples were counted with alpha 

detectors, which detect radioactivity rather than mass, there is no need to adjust measured air

concentration results for assumed uranium enrichment. 

Enriched and Recycled Uranium

Enrichment could affect assumptions about the radioactivity in the mass of the uranium released 

during processing, but AEC air sample results taken during the processing of enriched uranium, 

indicate that the airborne radioactivity concentrations during enriched uranium processing did not 

exceed those concentrations measured during processing of natural uranium. Because of the 

unknown enrichment and the unknown fraction of enriched material processed at Superior Steel, this 

document assumes that intakes are U234 for the purpose of internal dose calculation for an organ. 

Recycled uranium might have been processed at Superior Steel after 1952. An estimate of 

contaminants that might contribute the most to internal doses, based on a review of recycled uranium 

contaminants at Hanford and Fernald, is shown below. It is unlikely that recycled uranium would 

constitute the entire Superior Steel source term. Also, the activity fractions assume that the uranium 

specific activity is based on depleted uranium, which increases the proportion of the contaminants by 

activity. The contaminant levels for depleted uranium overestimate the contaminants in uranium of 

normal enrichment by about 40%. The contaminants are assumed to be oxides.

Table 5. Estimate of contaminant activity fractions in a recycled depleted uranium source term 

(pCi contaminant per pCi uranium). 

Uranium Pu-239 Np-237

1 0.00246 0.00182
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 16 of 23

3.2 OCCUPATIONAL INTERNAL DOSE RECONSTRUCTION ASSUMPTIONS AND 

SUMMARY

The assumed operational exposure period ran from January 1, 1952, to December 31, 1957. 

Table 6 lists intake rate assumptions for uranium-234. The intake mode is chronic. The dose 

distribution is assumed to be constant. 

Table 6. Internal exposure summary for operational period January 1, 1952, to December 

31, 1957. 

Start End

Intake 

route

Absorption 

type

Intake 

(pCi/calendarday)

U-234 1/1/1952 12/31/1957 Inhalation M, S 1.24E+04

1/1/1952 12/31/1957 Ingestion (a) 2.58E+02

Pu-239 1/1/1953 12/31/1957 Inhalation S 3.05E+01

1/1/1953 12/31/1957 Ingestion (a) 6.36E-01

Np-237

1/1/1953 12/31/1957 Inhalation M 2.25E+01

1/1/1953 12/31/1957 Ingestion (a) 4.69E-01

a. Choose same f1-value as used for inhalation per NIOSH (2004). 

4.0

No external dosimetry results are available for Superior Steel employees. This analysis estimated

dose, assuming that there was a potential for external exposure to natural uranium metal from five 

sources: 

ESTIMATION OF EXTERNAL EXPOSURE

• Submersion in air contaminated with uranium dust, 

• Exposure from contaminated surfaces, 

• Exposure to electrons from the surface of the uranium slabs and plates, 

• Exposure to photons from the uranium slabs and plates, and

• Exposure to an annual diagnostic X-ray.

The majority of photons from natural uranium metals are in the 30 to 250 keV energy range. Solid 

uranium objects provide considerable shielding of the lower energy photons and harden the spectrum, 

causing the majority of photons emitted from a solid uranium object, such as a thick plate, to have 

energies greater than 250 keV. While it is recognized that solid uranium sources will have a hardened 

photon spectrum, exposure to a thin layer of uranium on a surface will result in a larger fraction of 

exposure to lower energy photons. This analysis assumed workers were exposed to photon energies 

in the 30 to 250 keV range, which is claimant favorable. Nonpenetrating dose from natural uranium 

consists primarily of electrons with energies >15 keV. For consistent presentation, exposure or dose 

is reported as: 

• penetrating, assumed to be associated with photons of energies 30 keV or greater, and 

• nonpenetrating assumed to be associated with with photons of energies less than 30 keV or 

with electrons. 

Superior Steel processed some enriched uranium. Enriched uranium external doses would be similar 

or perhaps smaller than those from natural uranium. 
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 17 of 23

4.1 SUBMERSION AND CONTAMINATION EXPOSURES

Information regarding submersion and contamination exposures at Superior Steel is very limited, so 

data based on a survey at Simonds Saw and Steel, a rolling mill involved in uranium work for the 

AEC, was used to estimate these exposures. In a survey at Simonds Saw and Steel, the AEC 

suspended 20 film badges about 5 feet from the floor in the rolling mill for 192 consecutive hours “to 

determine the long term direct [external] radiation to individuals” (AEC 1949b). When the badges 

were retrieved, they were covered with radioactive dust from the plant, which would probably result in 

an overestimate of the true area radiation levels. The results of these measurements are assumed to 

represent the general levels of external exposure from submersion in air and contaminated surfaces 

at Simonds. This analysis assumed that the data distribution was lognormal. The calculated 

geometric means were 1.3 mR/h with a GSD of 2.3 for the nonpenetrating radiation, and 0.26 mR/h

with a GSD of 1.2 for the penetrating radiation. The maximum results were reported as 5.6 mR/h beta 

and 0.34 mR/h gamma. The beta reading is assumed to be related to the nonpenetrating dose and

the gamma reading is assumed to be related to the penetrating dose. These assumed exposures at 

Simonds during operational years are listed in Table 9. This analysis assumed that all workers were 

exposed to penetrating and nonpenetrating radiation from submersion in air and contamination for 

each workday for 8 hours/day. 

4.2 SLABS AND PLATES EXPOSURES

Another assumption was that workers received a deep dose due to photon exposure from the uranium 

slabs and plates. According to reports, the AEC work involved rolling uranium slabs 1 in. in thickness, 

61 to 89 in. long and 5.5 to 7 in. wide. The slabs were rolled into plates approximately 0.185 in. thick 

and 25 to 37 ft long cut into sections of about 6 ft. Monte Carlo N-Particle (MCNP) calculations 

determined the photon (including bremsstrahlung) dose rate at the surface, 1 ft, and 1 m from a 4 in. 

thick by 16 in. by 24-in. rectangular slab and a 0.18 in. thick by 3.5-in. by 18 in. plate. Table 7 lists 

calculated photon dose rates for the uranium billet and rod.

Table 7. Calculated photon dose rate for uranium slabs 

and uranium plates. 

Distance from source

Slab dose rate

(mrem/h)

Plate dose 

rate

(mrem/h)

Surface 8.26 6.27

1 ft 2.08 0.231

1 m 0.373 0.0278

No site-specific information was available to determine the amount of time a worker spent near the 

uranium forms versus just being in the general area. Records for similar facilities indicate that most 

workers spend less than 5 hours per shift near the uranium metals, but some workers may spend 7 

hours near the uranium metals. This analysis assumed that workers were near the slabs for 3.5 hours 

per rolling day and near the plates for 3.5 hours per rolling day. It also assumed that the dose rate at 

1 ft was the median dose rate, and the dose rate at the surface was the upper 95th percentile. 

The annual penetrating dose rates listed in Table 9 were calculated by multiplying the median photon 

dose rates by the number of rolling days per year and the 8 work-hours per day. 

Information regarding shallow doses at Superior Steel was unavailable. Nonpenetrating doses from 

the slabs and plates were estimated using the measurements in Table 8. These measurements were 

taken during an AEC survey in September 1948 (Belmore 1948) at Aliquippa Forge. Depleted 
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 18 of 23

uranium dose rate information reported by the Army (1989), indicating a dose rate of 0.205 rad/h at 7 

mg/cm2 at the surface of a clean bare uranium, was also used. Beta dose rates from depleted 

uranium are larger than dose rates from natural or enriched uranium, because of the larger activity 

fraction of 238U composition, whose progeny are the significant contributors to beta dose. 

Table 8. Direct radiation measurements from September 1948.

a

Location of measurement

Dose rate

(mrep/h)b

Contact with floor next to the quench tank where oxide scale has collected 8

Contact with floor in front of rolls where oxide scale has collected 5-10

Same location but 18” high 2-5

4 ft. above a pile of rods in the boxcar 20

5 ft. from the end of a pile of rods next to the door of the boxcar 5

2 ft. from the end of the same pile 13

a. Belmore 1948

b. A rep is an obsolete unit of dose equivalence (roentgen-equivalent-physical) approximately equal to a 

rem.

The largest dose rate in Table 8 was assumed to the median dose rate, because of the large surface 

areas of the plates and slabs. The 20 mrep/h was assumed to be equivalent to a dose rate of 20 

mrad/h. The upper 95th percentile dose rate was assumed to equal the 7 mg/cm2 dose rate of 205

mrad/h, giving a GSD of 4.1. These exposure rates were multiplied by the assumed number of 

uranium contact hours per day (3.5 for the slabs and 3.5 for the plates, respectively) and the number 

of rolling days per year (100). Table 9 lists these doses. 

4.3 OCCUPATIONALLY REQUIRED MEDICAL X-RAY

Information regarding whether or not occupationally required medical X-ray examinations were 

performed at Superior Steel is unavailable. AEC usually, but not always, required “preemployment” 

and periodic (annual) medical examinations of workers involved in the larger uranium processing 

programs. The term “preemployment” as used here, means prior to performing AEC-contracted 

radiological work. The typical AEC medical program included a preliminary chest x-ray examination

with annual examinations thereafter. The type and frequency of x-ray examination should be based 

on current ORAU Team guidance. Organ doses can be obtained from the current revision of ORAUTOTIB-0006, Technical Information Bulletin: Dose Reconstruction from Occupationally Related 

Diagnostic X-Ray Procedures (ORAUT 2003). 

4.4 MISCELLANEOUS INFORMATION RELATED TO EXTERNAL DOSE

This section includes external dose information that might be of interest for specific dose 

reconstructions. This analysis did not consider such information generically because of its limited 

applicability or because of limited information.

AEC noted that workers were sitting on the piles of uranium (AEC 1953b).
Effective Date: 08/09/2005 Revision No. 00 PC-1 Document No. ORAUT-TKBS-0034 Page 19 of 23

4.5 OCCUPATIONAL EXTERNAL DOSE RECONSTRUCTION ASSUMPTIONS AND 

SUMMARY

Table 9 summarizes occupational external doses during uranium operations at Superior Steel. A 

Superior Steel worker’s total external exposure for a given year of uranium operations is assumed to 

be the summation of the listed exposures in Table 9 for that year. 

Table 9. External exposure summary for operational period January 1, 1952, to December 31, 1957. 

Exposure 

mode

Exposure 

type

Exposure 

or dose 

rate Basis

Exposure 

time 

assumption Year

Annual 

exposure

IREP 

distribution

Submersion/

area 

contamination

Penetrating 0.26 

mR/h Film badge 2000

work-h/y

1952

1953

1954

1955

1956

1957

0.520 R

0.520 R 

0.520 R 

0.520 R 

0.520 R 

0.520 R

Lognormal

GSD 1.2

Nonpenetrating1.3 

mR/h Film badge 2000

work-h/y

1952

1953

1954

1955

1956

1957

2.600 R

2.600 R 

2.600 R 

2.600 R 

2.600 R 

2.600 R

Lognormal

GSD 2.3

Medical X-ray 

1952

1953

1954

1955

1956

1957

See ORAUT-OTIB-0006, 

(ORAUT 2003)

U slabs 

Penetrating 2.08

mrem/h

MCNP 

calculation

3.5

h/rolling-day

1952

1953

1954

1955

1956

1957

0.728 rem

0.728 rem

0.728 rem

0.728 rem

0.728 rem

0.728 rem

Lognormal

GSD 2.3

Nonpenetrating20 

mrad/h

Instrument 

measurement

3.5

h/rolling-day

1952

1953

1954

1955

1956

1957

7.0 rad

7.0 rad

7.0 rad

7.0 rad

7.0 rad

7.0 rad

Lognormal

GSD 4.1 

U plates

Penetrating 0.231

mrem/h

MCNP 

calculation

3.5

h/rolling-day

1952

1953

1954

1955

1956

1957

0.081 rem

0.081rem

0.081rem

0.081rem

0.081rem

0.081 rem

Lognormal 

GSD 7.4 

Nonpenetrating20 

mrem/h

Instrument 

measurement

3.5

h/rolling-day

1952

1953

1954

1955

1956

1957

7.0 rad

7.0 rad

7.0 rad

7.0 rad

7.0 rad

7.0 rad

Lognormal 

GSD 4.1

5.0

The residual dose period is assumed to begin on January 1, 1958 after the AEC rolling contract ended 

and to continue through the present. An 8-hour workday is assumed during this period. 

ESTIMATION OF RESIDUAL EXPOSURE
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 20 of 23

No surveys have been found to estimate the levels of radiation and contamination when the AEC work 

ended in 1957. ORNL (1981) performed a radiological survey in July 1980 to characterize the former 

Superior Steel site for FUSRAP. 

Only portions of the roughing (breakdown) mill were intact during the survey, all other 

machinery had been removed and sold or scrapped in previous years. The roughing mill has 

since been removed. Subfloor pits (approximately 8 ft. deep) over which the former mill, 

brushing station, finishing stands and shear were originally located were filled in with rubble, 

with final plans for concreting the surfaces over at floor level.

The former mill is presently [1980] being utilized in the rebuilding of coke oven doors. During 

the rebuilding process, significant quantities of fine coat is removed, part of which becomes 

airborne and settles out on surrounding surfaces. Use of this operation have resulted in 

coding the north end of the building with a layer of this material (up to 2 in. thick on the floor). 

Area B was being used for storage purposes in 1980. The two pits were being filled with rubble, with 

plans to concrete the floor level upon completion. The area was sealed off from the former mill (area 

A) area with a sheet metal wall and was being used primarily for storage. Parts of the roughing mill 

and the shear were in a storage warehouse on the industrial park.

ORNL used a gamma scintillation survey meter, a beta/gamma Geiger-Mueller tube with open/closed 

window, and an alpha scintillation meter for the 1980 survey. A summary of the 1980 survey results is 

shown in Table 10. 

Table 10. Superior Steel measured radiation levels on July 31, 1980a

. 

Location Alpha 

(dpm/100 

cm2

) 

U-238 

(pCi/g of 

soil or 

debris)

Contact 

(mrad/h)

Beta/gamma

Beta (mrad/h) Gamma 

(mR/h)

Area A 50 (maximum) 0.01 to 0.04

Area B <10 background

Area C (pit) 640 5800 0.8 0.3 0.5 (maximum)

Storage shed 50 1100 under 

floor

0.25 0.25 0.075 to 0.4

0.09 at 1 m 

from floor

Outside shed 0.2

Equipment in 

Storage

<10 0.03

a. ORNL (1981)

Uranium-238 is the predominant isotope by mass in natural uranium and is more easily identified 

than the other isotopes, so some may refer to uranium as uranium-238 rather than natural uranium, 

which consists of approximately equal activities of U-234 and U-238 and a smaller amount of U-235. 

Reported U-238 quantities may include all of the uranium activity or just part, depending on actual 

analysis techniques and reporting procedures.

Although the measured contamination levels were fairly low in 1980, the survey was hampered by 

limited access to surface. Also, there was no evidence that any cleanup had occurred at the time of 

contract termination. To calculate internal exposure from residual activity this analysis assumed that 

the median uranium exposure was associated with uniform contamination of the buildings to a level of

11,400 dpm/100 cm2

. This was the maximum removable contamination measured in May 1953, but is 
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 21 of 23

assumed to be the uniform surface contamination (fixed plus removable) during the residual 

contamination period. Using a resuspension factor of 1 × 10-6/m (NRC 2002b) and an air intake rate 

of 2,400 m3 per work year, the calculated uranium annual inhalation intake was 1,230 pCi. Using the 

method described in Section 3.0, the calculated annual ingestion intake was 25.7 pCi. It was 

assumed that the Pu-239 and Np-237 intakes occurred with the assumed uranium intakes at the 

ratios listed in Table 5. Table 11 summarizes residual period intake rates. 

To reconstruct external exposure to residual radioactivity after the end of AEC operations, this 

analysis assumed that workers were exposed to 0.09 mR/h penetrating radiation, which was the only 

available gamma exposure rate reading at 1 m. The residual penetrating radiation exposure is 

estimated by assuming that the 1-m value was the median rate and the maximum gamma exposure 

rate (0.5 mR/h) was the upper 95th percentile, which leads to a GSD of 2.82. The non-penetrating 

exposure rate was determined by assuming that 5.0, the ratio of non-penetrating to penetrating 

exposure rates for submersion and contamination external exposures during the operational exposure 

period, provided a reasonable estimate of the ratio of non-penetrating to penetrating exposure rate 

during the residual exposure period. The resulting non-penetrating exposure rate is 0.45 mR/h. A 

GSD of 3.8 for the non-penetrating dose rate was calculated by raising the number, e, to the square 

root of the sum of the squares of the lognormals of the GSDs of the three distributions (2.3, 1.2 and 

2.8) used to calculate the non-penetrating dose rate:

2

3

2

2

2

1 (ln( )) (ln( )) (ln( )) g g g

GSD e

σ + σ + σ

=

The estimated annual penetrating and non-penetrating external exposures to residual radioactivity 

from AEC operations at the site, listed in Table 11, were calculated by assuming that workers were 

exposed for 2,000 hours per year. 

Assumptions regarding residual exposures should be consistent with assumptions from the 

operational period.

Table 11. Annual internal and external exposure to residual radioactivity. 

Internal Start Endb Exposure

Absorption 

type

Intake

(pCi/d) IREP distribution

U-234 1/1/1958 Inhalation M, S 3.4E+00 Lognormal GSD 5

1/1/1958 Ingestion (a) 7.0E-02 Lognormal GSD 5

Pu-239 1/1/1958 Inhalation S 8.3E-03 Lognormal GSD 5

1/1/1958 Ingestion (a) 1.7E-04 Lognormal GSD 5

Np-237 1/1/1958 Inhalation M 6.1E-03 Lognormal GSD 5

1/1/1958 Ingestion (a) 1.3E-04 Lognormal GSD 5

External Start Endb Exposure Basis R/y

1/1/1958 Penetrating Survey Instrument 0.180 Lognormal GSD 2.8

1/1/1958 NonPenetratingSurvey Instrument 0.900 Lognormal GSD 3.8

a. Choose same f1-value as used for inhalation per NIOSH (2004). 

b. No end date is set, because there is no evidence that the site is restricted or has been remediated. 
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 22 of 23

REFERENCES

AEC (U.S. Atomic Energy Commission), 1949a, Contract AT-(30-1)-407, Supplemental Agreement 

No. 2, excerpt, April 21 [pp 95-102 of Simonds Saw and Steel Company.pdf]

AEC (U.S. Atomic Energy Commission), 1949b, Simonds Saw & Steel Co. Summary Report of Three 

Surveys (Oct. 27, 1948 – Feb. 15, 1949), 1949. [pp 249-254 of Simonds Saw and Steel 

Company.pdf]

AEC (U.S. Atomic Energy Commission), 1949c, Health Hazards in NYOO Facilities Producing and 

Processing Uranium: A Status Report, April 1, 1949, New York Operations Office, Medical 

Division, New York, New York.

AEC (U.S. Atomic Energy Commission), 1952, Contract AT-(30-1)-1413, excerpt, December 24 [pp. 

15-29 of 030001728.pdf]

AEC (U.S. Atomic Energy Commission), 1953a, Superior Steel Co., Air Dust Monitoring of Hot Strip 

Rolling of Uranium, Superior Steel-1, Health and Safety Division, New York Operations Office, 

May 22 [EmlBx17SupSteelCoAirDustMonRollingofUrMay1953.pdf] 

AEC (U.S. Atomic Energy Commission), 1953b., Superior Steel Co., Air Dust Monitoring of Hot Strip 

Rolling of Uranium, Superior Steel-2, Health and Safety Division, New York Operations Office, 

September 8 [EmlBx17SupSteelColAirDustRollingofUrSep1953.pdf] 

AEC (U.S. Atomic Energy Commission), 1955a, Superior Steel Company, Air Dust Monitoring of Hot 

Strip Rolling of Uranium, HASL-Superior Steel-3, Health and Safety Laboratory, New York 

Operations Office, July 1, [Eml2Bx18HaslSupSteel3AirDusMonHotStripRollJul1955.pdf] 

AEC (U.S. Atomic Energy Commission), 1955b, Superior Steel Company, Air Dust Monitoring of Hot 

Strip Rolling of Uranium, HASL-Superior Steel-4, Health and Safety Laboratory, New York 

Operations Office, November 15

[Eml2Bx18Hasl,SupSteel4AirDustMonitHotStripRollingUrNov1955.pdf] 

Army (U.S. Army Laboratory Command), 1989, Handbook of Safety Procedures for Processing 

Depleted Uranium, Chapter 3, Safety Considerations for Processing, Handling, and Testing of 

DU Components, AMC HDBK 385-1.1-89, Department of the Army, Washington, D.C., August, 

pp 3.5 – 3.12

Belmore, F. M., 1948, letter to J. O. Flower (Vulcan Crucible Steel Company), October 22, no subject, 

U.S. Atomic Energy Commission, New York Operations Office, New York, New York 

[260000126.pdf]

DOE, 2005, Office of Worker Advocacy, accessed on February 25

[http://www.eh.doe.gov/advocacy/faclist/showfacility.cfm ] 

E. I. du Pont de Nemours & Co., 1954, “Report No. 5, Flat Bonded Fuel Elements, Period February 11 

–April 10, 1954,” DPW-54-19-5, Explosives Department – Atomic Energy Division, Wilmington, 

Delaware. [10192556.pdf]

Eidson, A. F., 1994, “The effect of solubility on inhaled uranium compound clearance: a review,” 

Health Physics, volume 67 number 1, pp. 1-14
Effective Date: 05/03/2005 Revision No. 00 Document No. ORAUT-TKBS-0034 Page 23 of 23

Harris, W. B., 1953, memorandum to G. E. Dunlop (Production Division), “Survey Report Superior 

Steel-2,” September 21 [p 1 of EmlBx17SupSteelColAirDustRollingofUrSep1953.pdf]

Heffernan, T. E., J. C. Lodwick, H. Spitz, J. Neton, and M. Soldano, 2001, “Solubility of airborne 

uranium compounds at the Fernald Environmental Management Project,” Health Physics, 

volume 80, number 3, pp. 255-262.

ICRP (International Commission on Radiological Protection), 1994a, Human Respiratory Tract Model 

for Radiological Protection, Publication 66, Pergamon Press, Oxford, England.

ICRP (International Commission on Radiological Protection), 1994b, Dose Coefficients for Intakes of 

Radionuclides by Workers, Publication 68, Pergamon Press, Oxford, England.

ICRP (International Commission on Radiological Protection), 1995, Age-dependent Doses to 

Members of the Public from Intake of Radionuclides: Part 4 Inhalation Dose Coefficients, 

Publication 71, Pergamon Press, Oxford, England.

NIOSH (National Institute for Occupational Safety and Health), 2004, Estimation of Ingestion Intakes, 

Technical Information Bulletin, OCAS-TIB-009, Revision 0, April 13, Office of Compensation 

Analysis and Support, Cincinnati, Ohio.

NRC (U.S. Nuclear Regulatory Commission), 2002a, Technical Basis for Calculating Radiation Doses 

for the Building Occupancy Scenario Using the Probabilistic RESRAD-BUILD 3.0 Code, 

NUREG/CR-6755, Washington, D.C.

NRC (U.S. Nuclear Regulatory Commission), 2002b, Re-evaluation of the Indoor Resuspension 

Factor for the Screening Analysis of the Building Occupancy Scenario for NRC’s License 

Termination Rule, NUREG-1720; Draft Report for Comment, Washington, D.C.

ORAUT (Oak Ridge Associated Universities Team), 2003, Technical Information Bulletin: Dose 

Reconstruction from Occupationally Related Diagnostic X-Ray Procedures, 

ORAUT-OTIB-0006, Revision 2, December 29, Oak Ridge Associated Universities, Oak 

Ridge, Tennessee.

ORNL (Oak Ridge National Laboratory), 1981, Preliminary Site Survey Report for the Former Superior 

Steel Mill at Carnegie, Pennsylvania, Contract No. W-7405-eng-26, Oak Ridge, Tennessee, 

April [030001729.pdf]

Young, C. D., 1985, letter and enclosure to A. Whitman (USDOE), Authority Review – The Former 

Superior Steel Corporation Site – AEC Contract No. AT(30-1- 1412, The Aerospace 

Corporation, Washington, D.C. September 1985, [pp 3-14 of 030001728.pdf]