National Institute for Occupational Safety and Health

SEC-00247

Superior Steel Co.

Megan Lobaugh, PhD, CHP

Health Physicist

Advisory Board on Radiation and Worker Health, 126th Meeting

Redondo Beach, CA

December 12-13, 2018
About Superior Steel Co. Site

 Carnegie, PA

• 5 inter-connected buildings

 Uranium rolling for AEC

 Covered Period

• AWE: January 1, 1952 

through December 31, 1957

• Residual Radiation: January 

1, 1958 through present

Photo from USACE, 2018
Superior Steel Co. Processing Areas

From Myrick, 1981

From Myrick, 1981
SEC-00247 Petition for Superior Steel Co.

 83.13 (Form B) Petition Received May 1, 2018

– Petitioner-requested class: All workers who worked in any area at 

the Superior Steel Co. facility in Carnegie, PA, during the period from 

January 1, 1952 through December 31, 1957.

– (F.1) Basis: Radiation exposures potentially incurred by members of 

the proposed class were not monitored either through personal 

monitoring or through area monitoring.

 Petition qualified on July 19, 2018

– Qualified class: All atomic weapons employees who worked in any 

area at Superior Steel Co. in Carnegie, PA during the period from 

January 1, 1952 through December 31, 1957.
Number of Superior Steel Co. Claims 

(as of October 2, 2018)

Description Totals

Total number of claims submitted for dose reconstruction 35

Total number of claims submitted for energy employees who worked 

during the period under evaluation (January 1, 1952 through 

December 31, 1957)

35

Number of dose reconstructions completed for energy employees 

who worked during the period under evaluation 35

Number of claims for which internal dosimetry records were obtained 

for the time period under evaluation 0

Number of claims for which internal dosimetry records were obtained 

for the time period under evaluation 0
Superior Steel Co. Exposure Time

 AEC contract [AT(30-1)-1412] effective date is June 27, 1952 

 AEC contract end date is September 30, 1957 

– Evidence that the fission material accounting station authority was 

withdrawn on November 27, 1957

 AEC cost-plus-fixed-fee contract was for intermittent, on-demand rolling

 Payments to Superior Steel Co. through fiscal year 1957 totaled $356,849 

 CATI information tells us overtime work was common
Radiological Sources at Superior Steel Co.

 Majority of AEC rolling campaigns were with natural uranium metal

 1 AEC rolling campaign included 6 slabs of 1.5% enriched uranium metal

 Since the Superior Steel Co. operations were after 1952, uranium metal 

could be recycled

 1 commercial, small-scale rolling campaign with 700 pounds of thorium 

metal
AEC Licensing for Thorium at Superior Steel Co.

 March 27, 1956: AEC license “to receive, possess, use, and transfer” 700 

pounds of thorium metal from Babcock and Wilcox (B&W) to perform 

studies similar to work done for AEC

 April 20, 1956 and April 23, 1956: Superior Steel Co. request for license 

amendment for unlimited quantities of thorium metal owned by 

Consolidated Edison to be used by B&W in critical experiments; mentions 

data from test rollings

 April 30, 1956: Licensed by AEC for unlimited quantities of thorium metal 

with expiration on April 30, 1958
Thorium Rolling at Superior Steel Co.

 No evidence of shipping, receiving, or rolling of thorium in document reviews

 5 radiological surveys done in support of more recent clean-up efforts

– Gamma spectroscopy of soil and other samples taken from inside buildings 

• Uranium contamination found, as expected

• No evidence of thorium contamination

– Gamma scan survey of land surrounding facility

• Uranium contamination found in spatial distribution around buildings

• Background levels and spatial distribution typical of naturally-occurring 

thorium 

 NIOSH concludes no large-scale use of thorium at Superior Steel Co.
Internal Exposure Routes at Superior Steel Co.

 Inhalation and ingestion of uranium and thorium metal and oxidized 

material via:

– Dispersion during rolling and related processes 

– Dust-settling of contamination

– Resuspension of contamination
External Exposure Scenarios at Superior Steel Co.

 Photon and beta radiation from uranium and thorium metal ingots and 

slabs via:

– Direct exposure 

– Exposure from the contaminated surfaces within the facility

– Submersion in contaminated air within the facility

 Occupational Medical X-rays
Monitoring Data AvailableInternal Exposure at Superior Steel Co.

 Personal Monitoring: No in vitro or in vivo results and there is no 

indication of internal dosimetry monitoring program. 

 Area Monitoring: Four campaigns of air monitoring (e.g., BZ and area) 

performed by AEC Health and Safety Laboratory (HASL) during uranium 

rolling:

– May 13, 1953 

– August 3, 1953 

– May 9, 1955 

– September 19, 1955
Summary of Breathing Zone Air Monitoring DataUranium Rollings

Date # of 

Samples

Highest Alpha 

Recorded dddddd

3

Location of Highest 

Value Reference

May 9, 1955 9 38,500 Stamping Plate 

(manual operation) AEC, 1955a

September 19, 1955 6 18,000 Stamping 3 sections 

of plate AEC, 1955b
Summary of Area Air Monitoring DataUranium Rollings

Date # of 

Samples

Highest Alpha 

Recorded dddddd

3

Location of 

Highest 

Value

Reference

May 13,1953 28 13,200 A Klevin, 1953a

August 3,1953 33 49,110 B Klevin, 1953b

May 9, 1955 61 1,800 C AEC, 1955a

September 19, 1955 38 3,320 D AEC, 1955b

D C B A

From Myrick, 1981
Monitoring Data and Information AvailableExternal Exposure at Superior Steel Co.

 Personal Monitoring: No external dosimetry results and there is no 

indication of external dosimetry monitoring program.

 Area Monitoring: No indication of area external dose monitoring program.

 Information is available to NIOSH about the Superior Steel Co.’s AEC 

contract, radiological material licensing, processes, and the material 

processed.
NIOSH Proposed Dose Reconstruction MethodsApplicable Years 

 Uranium

• Operations:

• June 27, 1952 through 

December 31, 1957

• Residual Contamination:

• January 1, 1958 through 

present

 Thorium

• Operations:

• March 27, 1956 through 

April 20, 1956

• Post-Ops Contamination:

• April 21, 1956 through 

December 31, 1957

• Commercial, non-AEC work
NIOSH Proposed Dose Reconstruction MethodsInternal Exposures (1952-1957)

Intake 

Information Uranium Thorium

Rolling 500 h per year

U air concentration results

10 h during March – April 1956 

Th air concentration calculated using 

a mass loading approach

Resuspension 2000 h per year U resuspension Remainder of 1956 and all of 1957 

Th resuspension

Material 

Assessed as

U-234 including recycled U 

contaminants

Th-232 including Th daughter 

products in secular equilibrium
NIOSH Proposed Dose Reconstruction MethodsExternal Exposures (1952-1957)

Exposure Type Uranium Thorium

Direct Rolling

500 h per year

Battelle-TBD-6000 

rolling operations dose

10 h in March – April 1956

MCNP modeling and distance guidance 

in Battelle-TBD-6000

Submersion 

Rolling

500 h per year submersion 

using DCF from EPA-FGR-12

10 h in March – April 1956 submersion 

using DCF from EPA-FGR-12 

Direct Storage

500 h per year 

Battelle-TBD-6000

1m dose rate

190 h in March – April 1956

MCNP modeling for dose rate at 1m

Post-rolling

2000 h per year submersion 

and direct exposure using 

DCF from EPA-FGR-12

Remainder of 1956 and all of 1957 

submersion and direct exposure using 

DCF from EPA-FGR-12
Dose Reconstruction Feasibility Conclusion

 NIOSH has sufficient air data and process information to bound internal 

and external dose from AEC uranium metal rolling operations.

 NIOSH has sufficient process information to bound internal and external 

dose from the small-scale, commercial thorium metal rolling operation.

 The NIOSH Site Profile for Superior Steel Co. (effective date 2005) will be 

updated with the additional information captured and reviewed in this 

evaluation.
Evaluation of Petition Basis- Internal Monitoring

 “Individual uranium urinalysis data are unavailable for Superior Steel Workers and 

none are known to exist.” (ORAUT-TKBS-0034)

– When personal internal monitoring data are unavailable, NIOSH uses air 

monitoring data from worker breathing zones and work areas, in accordance 

with NIOSH’s OCAS-IG-002, Internal Dose Reconstruction Implementation 

Guideline.

– Sufficient site-specific air monitoring data and process data to calculate 

estimates of worker internal uranium doses with sufficient accuracy

– Airborne mass loading calculations using available uranium process air 

monitoring data to estimate worker internal thorium doses
 “No external dosimetry results are available for Superior Steel employees.”

(ORAUT-TKBS-0034)

– When personal and area external monitoring data are unavailable, NIOSH uses 

workplace information (e.g., source term, process) to estimate dose, in 

accordance with NIOSH’s OCAS-IG-001, External Dose Reconstruction 

Implementation Guideline.

– Sufficient applicable site-specific information, using the methods of BattelleTBD-6000, to model potential external uranium exposures

– Model thorium metal related exposures in accordance with the methods 

presented in Battelle-TBD-6000 using MCNP

Evaluation of Petition Basis- External Monitoring
Feasibility Findings for SEC-00247 Superior Steel Co. 

January 1, 1952 to December 31, 1957

Source of Exposure Dose Reconstruction Feasible

Internal Yes

Uranium Yes

Thorium Yes

External Yes

Uranium Yes

Thorium Yes

Occupational Medical X-rays Yes
References

 AEC, 1955a, Superior Steel Company Air Dust Monitoring of Hot Strip Rolling of 

Uranium; U.S. Atomic Energy Commission (AEC) Health and Safety Laboratory 

(HASL); issued July 1, 1955; SRDB Ref ID: 6877

 AEC, 1955b, Superior Steel Company Air Dust Monitoring of Hot Strip Rolling of 

Uranium; U.S. Atomic Energy Commission (AEC) Health and Safety Laboratory 

(HASL); issued November 15, 1955; SRDB Ref ID: 6888

 Klevin, 1953a, Superior Steel Company Air Dust Monitoring of Hot Strip Rolling of 

Uranium; Paul B. Klevin, Industrial Hygiene Branch Health and Safety Division; 

issued May 22, 1953; SRDB Ref ID: 6898

 Klevin, 1953b, Superior Steel Company Air Dust Monitoring of Hot Strip Rolling of

Uranium; Paul B. Klevin, Industrial Hygiene Branch Health and Safety Division;

issued September 8, 1953; SRDB Ref ID: 6899, PDF pp. 2-12
References- continued

 Myrick, 1981, Preliminary Site Survey Report for the Former Superior Steel Mill at 

Carnegie, Pennsylvania; T. E. Myrick and C. Clark, Oak Ridge National Laboratory; 

April 1981; SRDB Ref ID: 14657

 USACE, 2018, Superior Steel Site Fact Sheet (January 2018), U.S. Army Corps of 

Engineers- Buffalo District, Environmental Project Management Team; January 

2018; SRDB Ref ID: 173724