National Institute for Occupational Safety and Health

SEC-00256 Pinellas Plant

Evaluation Report

Megan Lobaugh, PhD, CHP

Research Health Physicist

Advisory Board on Radiation and Worker Health, 143rd Meeting

December 8-9, 2021
About Pinellas Plant

 Clearwater, FL

– 99.9-acre site midway between 

Largo and Pinellas Park, FL

 Produced high-technology nuclear 

weapons-related components

 Timeline

– Operations: 1957 – September 1994

– D & D: October 1994 – 1997

– Remediation: 1999, 2008 – 2009

Photo from Gueretta 2015

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Pinellas Plant

 Employed about 2000 people at 

its peak

 Manufactured neutron 

generators for first 10 years

 Expanded mission to include 

other specialized electronic and 

support components

• Specialty capacitors, LAMB 

batteries, vacuum switch tubes, 

RTGs

Figure from Martin Marietta 1993a

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SEC-00256 Petition for Pinellas Plant

 83.13 Petition received December 16, 2019

– Revised on May 20, 2020 and August 17, 2020

 Temporary Plant in St. Petersburg (prior to 1957) not covered

 Final Petitioner-Requested Class:

– All employees who worked in any area of the Pinellas Plant in Largo, FL 

from January 1957 through December 1997.

 Extensive supporting documentation

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SEC-00256 Petition Qualification

 Petition qualified for evaluation October 20, 2020

– (F.4) Basis: Tiger Team Assessment of the Pinellas Plant [DOE 1990a] 

discussed bioassay compliance (i.e., samples not being submitted)

 Class defined by NIOSH for further evaluation:

– All employees of the Department of Energy, its predecessor agencies, 

and their contractors and subcontractors who worked at the Pinellas 

Plant in Clearwater, Florida for the period from January 1, 1957 

through December 31, 1990.

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Number of Pinellas Plant Claims

(as of May 3, 2021)

Description Totals

Total number of claims submitted for dose reconstruction 503

Total number of claims submitted for energy employees who worked 

during the period under evaluation (January 1, 1957 through December 

31, 1990)

496

Number of dose reconstructions completed for energy employees who 

worked during the period under evaluation 456

Number of claims for which NIOSH obtained internal dosimetry records 

for the time period in the evaluated class definition 279

Number of claims for which NIOSH obtained external dosimetry records 

for the time period in the evaluated class definition 277

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Internal Radiological Exposure Sources

 Tritium

• Tritiated water (HTO), 

Tritium gas, Organically 

bound tritium (OBT), Metal 

tritides (MT)

 Not internal dose concerns

• Kr-85 (noble gas) 

• Plutonium (encapsulated RTG source)

• Uranium (contained in tritium storage 

and borosilicate glass)

• C-14 (negligible quantity used in 

labeling)

• Ni-63 (contained in vacuum tubes)

• Cs-137 and other sealed sources

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Monitoring Data- Internal Exposure

 Tritium urine bioassay with routine schedule frequencies (i.e., daily or on 

each performance, weekly, monthly) based on exposure potential

– Detailed internal dose data for all years under evaluation

 Plutonium urine bioassay annually for the RTG project workers

 Area air monitoring in areas with potential for tritium release and for 

plutonium in RTG area

 Routine smear survey monitoring for tritium in areas with potential for 

tritium release and for plutonium in RTG area

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Summary of Pinellas Plant Internal Monitoring 

1986-1995

Year Number 

Monitored

Total Dose

(person-mrem)

Average Dose 

(mrem)

Highest Individual 

Dose (mrem)

1986 194 699 3.60 86

1987 139 358 2.58 105

1988 129 565 4.38 130

1989 201 557 2.77 97

1990 177 184 1.04 31

1991 202 390 1.93 101

1992 164 150 0.91 35

1993 134 103 0.77 21

1994 217 17 0.08 6.3

1995 215 224 1.04 93

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External Radiological Exposure Sources

 Photon- testing neutron tubes and neutron generators, RTG work, ion 

accelerator, Kr-85 component leak testing

 Beta- Kr-85 component leak testing incidents, x-ray diffraction and e-beam 

device incidents

– Tritium not an external dose hazard due to low energy beta 

– C-14 quantities considered negligible

 Neutron- neutron generator testing, RTG, ion accelerator

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Monitoring Data- External Exposure

 Monitored workers with potential for radiological exposure and routinely 

entered radiation areas

– Individual monitoring is available for the entire evaluation period

 Typical personnel external monitoring exchange frequency was monthly 

until January 1990 when it switched to quarterly

 Area monitoring consisted of direct radiation surveys, area film 

monitoring, and work support surveys

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Summary of Pinellas Plant External Monitoring 

1985-1995

Year Number 

Monitored

Total Dose

(person-mrem)

Average Dose 

(mrem)

Highest 

Individual Dose 

(mrem)

1985 Not Reported 5,525 Not Reported 411

1986 Not Reported 2,837 Not Reported 550

1987 Not Reported 2,102 Not Reported 321

1988 171 1,712 6.7 170

1989 187 1,847 4.9 180

1990 185 2,104 8.3 280

1991 107 830 3.9 40

1992 117 350 1.7 30

1993 88 270 2.3 50

1994 80 60 0.5 20

1995 72 243 0.28 10 12
Qualifying Petition Basis

From the Tiger Team Assessment of the Pinellas Plant: 

 “GEND estimated that 20 percent of the personnel that terminated in 

1988 did not provide a termination bioassay.” [DOE 1990a, PDF p. 224]

 “Seventy percent of the required monthly samples and 35% of the 

required weekly samples were not submitted.” [DOE 1990a, PDF p. 224]

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Evaluation of Qualifying Petition BasisTermination Bioassays

“GEND estimated that 20 percent of the personnel that terminated in 1988 

did not provide a termination bioassay.” [DOE 1990a, PDF p. 224]

 Termination bioassay data are available to NIOSH

 Due to the short biological half-life of tritium, termination samples only 

provide an indication of exposure just preceding the sample collection

 NIOSH finds dose reconstruction feasible

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Evaluation of Qualifying Petition BasisRoutine Samples

“Seventy percent of the required monthly samples and 35% of the required 

weekly samples were not submitted.” [DOE 1990a, PDF p. 224]

 Interviews with 16 former workers and DOE oversight staff

– Pinellas Plant employees generally compliant

– Did not know of workers not submitting samples as requested

– Ideas as to why monitoring compliance was not at the desired level:

• Employees with non-routine entries to tritium areas added to 

routine monitoring

• Leave/vacation

 Review of NOCTS claims for consistency in monitoring

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Evaluation of Qualifying Petition BasisRoutine Samples (continued)

“Seventy percent of the required monthly samples and 35% of the required 

weekly samples were not submitted.” [DOE 1990a, PDF p. 224]

 No increase in site-wide or individual average internal dose after increase 

in compliance

– No significant internal dose went unmonitored

 Most highly exposed workers (i.e., those on weekly monitoring) more 

compliant

– Dataset available from monitored workers is likely biased high

 Doses for monitored workers are low

– Can bound tritium dose

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Conclusion: Evaluation of Qualifying Petition BasisRoutine Samples

“Seventy percent of the required monthly samples and 35% of the required 

weekly samples were not submitted.” [DOE 1990a, PDF p. 224]

 Unmonitored Dose

– Current External TBD assigns 100mrem dose

– Based on whole body dose data from monitored workers

• external WB + tritium internal

– Update to Internal TBD

 Approaches to assign dose to workers with gaps in monitoring

 NIOSH finds dose reconstruction is feasible

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Feasibility Findings for Pinellas Plant

SEC-00256

Internal Source of Exposure Dose Reconstruction 

Feasible?

Tritium Yes

Plutonium, uranium, carbon-14, 

nickel-63, krypton-85 Not Applicable

External Source of Exposure Dose Reconstruction 

Feasible?

Beta, gamma, neutron Yes

Occupational Medical Yes

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Questions?