Insoluble Particulate Tritium 
 

Example Dose Reconstruction
 

for the
 

Pinellas Plant
 

National Institute for Occupational
 

Safety and Health
 

February 3, 2016 

Mutty M. Sharfi
 

Oak Ridge Associated Universities Team
 

-

Reviewed by Jim Neton, CHP and Peter Darnell, CHP, RRPT
 

Division of Compensation Analysis and Support
 

NOTICE: This report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 USC §552a and has been cleared for distribution. 
 02/03/2016 Page 2 of 5 

NOTICE: This report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 USC §552a and has been cleared for distribution. 

 

 

 

 

 

 

 

 

 

 

 

Pinellas Plant 

Insoluble Tritium Example Dose Reconstruction for Advisory Board

Employee Information 

Cancer Description:	 Lung (ICD-9: 162); diagnosed 12/31/2015 

Liver (ICD-9: 155); diagnosed 12/31/2015 

Prostate (ICD-9: 185); diagnosed 12/31/2015 

BCC (ICD-9: 173); diagnosed 12/31/2015 

SCC (ICD-9: 173); diagnosed 12/31/2015 

Year of birth: 1932 

Gender: Male 

Smoking: Never Smoked 

Ethnicity: “White, non-Hispanic” 

Employment Information 

Start date: 01/01/1957 

End date: 12/31/1997 

Occupation: Unknown 

Dosimetry Data: None 

Organ Dose Assessed 1 

Cancer External Organ Used Internal Organ Used 

Lung Lung Lung 

Liver Liver Liver 

Prostate Urinary Bladder Heart Wall2 

Skin Skin Skin 

1. ORAUT-OTIB-0005 

2. Non-metabolic organ with the highest dose. 

External Dose 

Not applicable for tritium exposures. 

Internal Dose 

At the Pinellas Plant, insoluble particulate tritium [i.e., metal tritides (MT) and certain more 

insoluble forms of organically bound tritium compounds (insoluble OBT)] were handled in areas 

where the more dispersible and soluble forms of tritium [i.e., elemental tritium (HT), tritiated 

water (HTO), and certain more soluble forms of organically bound tritium compounds (soluble 

OBT)] were present. A review of the available dosimetry records indicates that the Pinellas 

Plant routinely monitored workers with any potential for exposure to tritium with bioassay (i.e. 

urinalysis) due to the potential exposure to the more soluble forms. This means that workers 
 02/03/2016 Page 3 of 5 

NOTICE: This report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 USC §552a and has been cleared for distribution. 

 

 

 

Pinellas Plant
 

Insoluble Tritium Example Dose Reconstruction for Advisory Board

with potential exposure to insoluble particulate tritium can be identified by the fact that they 

would have been included in the standard tritium bioassay program. Therefore, the insoluble 

particulate tritium intake rates below are applied only to the periods that workers were monitored 

for tritium via bioassay. 

Contamination Levels 

The available information on the Pinellas Plant indicates that only a relatively small portion of 

the Pinellas Plant’s workforce had the potential to be exposed to dispersible forms of insoluble 

particulate tritium, and those scenarios were typically limited to accidents. The available 

incident information in the monthly health physics reports (SRDB 13358, 27095, 133577, 

133579, 133580, 133581, 133583, 133586, and 133591) indicate that when the contamination 

levels exceeded the control level, the affected areas were cleaned up immediately. These 

monthly health physics reports indicate that as early as 1959, areas greater than 2×10-5 μCi/in2 

(688 dpm/100 cm2) were recommended for decontamination. In 1969, the control limit was 

reported as 440 dpm/100 cm2

. This indicates that a routine contamination control program was in 

place throughout the history of the site and that it would be unlikely to see high contamination 

levels for extended periods of time. This was confirmed in an interview of a former radiological 

control employee (SRDB 127111) who indicated that metal tritide contamination was cleaned up 

fairly quickly. They indicated that radiological control personnel would take wipes in the 

morning and, if contamination was identified, they would then mop up the area and re-survey. 

The likelihood of routine high surface contamination level should be considered unusual and 

short in duration. 

The source of the contamination indicated in these reported incidents are generally not associated 

with insoluble particulate tritium. Rather, they are associated with loaded glass tubes of tritiated 

gas (HT) that were dropped releasing the tritium gas or from maintenance activities (which 

would likely be associated with soluble OBT). Exposures associated with these types of releases 

would be captured in the assessment of the individual’s tritium bioassay. 

The monthly health physics reports also provide information on the maximum tritium surface 

contamination levels. Between 1957 and 1973, the highest surface contamination level identified 

in the health physics reports was in 1970, 4.4×106

 dpm/100 cm2 (10,000 times the control limit). 

This incident was actually associated with maintenance activities and not insoluble particulate 

tritium. There were three other instances where contamination levels were reported as greater 

than 1×106

 dpm/100 cm2. None of these instances were associated with insoluble particulate 

tritium. The majority of the rest of the maximum surface contamination levels reported in the 

monthly health physics reports are at least an order of magnitude or more lower than these. 

The Mound Plant was a facility that performed insoluble particulate tritium work similar to the 

Pinellas Plant. The highest annual 95th percentile surface contamination level associated with 

SW-8 and R-108 at the Mound Plant was less than 3×105 dpm/100 cm2. This is about an order of 

magnitude lower than the maximum surface contamination level identified at the Pinellas Plant. 
 

 

 

 

 

 

Pinellas Plant
 

Insoluble Tritium Example Dose Reconstruction for Advisory Board

Therefore, the use of a constant contamination level of 4.4×106 dpm/100 cm2 at the Pinellas 

Plant is considered bounding and favorable to the claimant. 

Resuspension Factors 

Based on a review of various methodologies for other sites, a resuspension factor of 1×10-6 m-1is 

generally used for decontaminated undisturbed areas; whereas, a resuspension factor of 1×10-5 

m-1 or greater is generally used for areas with ongoing operations in areas with a significant 

amount of loose contamination. The assumption for the Mound Plant is a resuspension factor of 

5×10-5 m-1 . The Pinellas Plant was aware of the impact of contaminated areas and worked to 

maintain a clean work environment when contamination was identified, therefore a resuspension 

factor of 1×10-6 to 1×10-5 m-1 is probably more consistent with the conditions at the Pinellas 

Plant. However, given that the type of tritium work and facilities at Pinellas are similar to those 

at Mound, the more favorable to the claimant resuspension factor of 5×10-5 m-1 will be used. 

Intake Analysis 

Based on the information above, the bounding potential unmonitored insoluble particulate tritium 

exposure will be based on: 

• Constant surface contamination level of 4.4×106 dpm/100 cm2 (4.4×108 dpm/m2) 

• Resuspension factor of 5×10-5 m-1 

This resulted in a calculated particulate tritium air concentration of 24,200 dpm/m3

. Applying a 

breathing rate of 1.2 m3

/hour and an exposure time assumption of 50-hour weeks (based on a 

review of telephone interviews provided by former workers) for 52 weeks per year (2,600 hours 

total per year), the annual inhalation and ingestion intake rates for insoluble particulate tritium 

were calculated and are provided in the table below. Ingestion rates are based on guidance from 

OCAS-TIB-0009. 

Inhalation Ingestion 

3.09×107 pCi/year 

8.47×105 pCi/calendar day 

5.80×105 pCi/year 

1.59×103 pCi/calendar day 

These values account for only potential insoluble particulate tritium intakes. Exposure to soluble 

forms of tritium (HT, HTO, and soluble OBT) will be assessed based on the worker’s tritium 

bioassay data. The assessment of tritium bioassay (i.e., soluble forms of tritium) is not covered 

in this example dose reconstruction. 

Solubility Types M and S tritiated compounds were present at the Pinellas Plant. There is limited 

information to clearly indicate which form of insoluble tritiated compound(s) a worker might 

have been exposed to, the potential exposures are based on the more favorable to the claimant 

solubility type. 

 02/03/2016 Page 4 of 5 

NOTICE: This report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 USC §552a and has been cleared for distribution. 
 

 

 

Pinellas Plant
 

Insoluble Tritium Example Dose Reconstruction for Advisory Board

Uncertainty 

Because the assigned intakes represent an upper-bound for the energy employee’s potential 

unmonitored insoluble particulate tritium intakes, all doses are applied as a constant distribution. 

Summary 

The assessment methods presented in this report define the methods by which a dose estimate 

can be determined for the evaluated worker class. These methods support NIOSH’s conclusion 

that the operationally-related internal dose for the evaluated worker class can be bounded. A 

summary of the doses and probability of causations are provided below. 

Cancer External 

(rem) 

Internal 

(rem) 

Total 

(rem) 

Probability of 

Causation 

Lung 4.632 4.632 22.12% 

Liver 0.009 0.009 0.12% 

Prostate n/a 0.009 0.009 0.02% 

Skin BCC 0.009 0.009 0.04% 

Skin SCC 0.009 0.009 0.01% 

 02/03/2016 Page 5 of 5 

NOTICE: This report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 USC §552a and has been cleared for distribution.