Office of Compensation Analysis and Support 

(OCAS) 

Document No. OCAS-IG-004 

Effective Date: August 21, 2008 

Revision No. 0 

The Use of Data from Other Facilities in the Completion 

of Dose Reconstructions Under the Energy Employees 

Occupational Illness Compensation Program Act 

Page 1 of 11 

Approval: _______Signature on File_____Date: _8/21/2008_

 J. W. Neton, Assoc. Dir. for Science 

Concurrence: ___Signature on File _____Date: _8/21/2008_

 L. J. Elliott, Director 

Supersedes: 

None 

Table of Contents 

Section Title Page

1.0 Introduction........................................................................3 

2.0 Precedence for the Use of Surrogate Data................................5 

3.0 Criteria for the Use of Surrogate Data.......................................6 

4.0 Examples...........................................................................9 

5.0 References.......................................................................10 
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Record of Issue/Revisions 

Issue 

Authorization 

Date 

Effective 

Date 

Revision 

No. 

Description 

August 21, 2008 August 21, 

2008 

0 Guidelines for the use of data from other 

facilities in the completion of dose 

reconstructions 
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1.0 INTRODUCTION 

The basic principle of dose reconstruction is to characterize the radiation 

environments to which workers were exposed and then place each worker in 

time and space within this exposure environment. Methods are then applied to 

translate exposure to radiation into quantified radiation doses at the specific 

organs or tissues relevant to the types of cancer occurring among the workers. 

To ensure accuracy and completeness, a dose reconstruction should consider all 

relevant monitoring data in the evaluation of exposure. Because personnel 

monitoring data is specific for an individual, it should be given the most weight in 

retrospectively evaluating exposure. This assumes, of course, that the data have 

been determined to provide an accurate characterization of the exposure 

environment. That is, the data have been reviewed for the following: 1) the 

validity of the measurement method for the workplace exposure condition being 

evaluated; 2) the detection limit of the process used; and, 3) the 

representativeness of the data to the segment of the workforce to which it is 

applied. 

When personnel monitoring data are unavailable or limited in number as to be 

unrepresentative, workplace measurements, such as air samples or area 

measurements of external dose may be used. Lacking the above, information 

about the sources and types of radiation present at a facility and the process 

operations involving the radioactive materials may be used to construct a model 

to estimate worker exposure. Table 1 provides a listing of the hierarchical 

approach to data source usage that is prescribed in NIOSH’s dose reconstruction 

regulation (USHHS 2002). 

Table 1: Hierarchy of data sources used in the reconstruction of doses1

Hierarchy Data source Examples 

1 Individual monitoring 

data 

In-vivo analyses, in-vitro analyses, 

breathing zone air samples, external 

dosimeters 

2 Individual monitoring 

data of coworkers2

Information based on in vitro bioassays or 

film badge measurements of coworkers 

3 Workplace monitoring 

data 

General work area air samples or area 

themoluminescent dosimeters 

4 Source term data and 

process information 

Identification of radionuclides and 

quantities available for dispersal, along 

with knowledge of process information 

 

1

 As described in 42 C.F.R. 82.2

2 Coworkers are considered to be workers at a site (potentially grouped by work location, job description, or 

other appropriate category) whose radiation monitoring measurements are considered to be representative 

of those received by one or more workers with no individual monitoring data. 
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When the source term and process information (hierarchy #4) for a particular 

facility need to be supplemented to adequately characterize the workplace 

exposure conditions, it may be necessary to rely on data from another facility to 

completely develop an exposure model. The data, which could be obtained from 

any of the first three sources listed in Table 1, are referred to as surrogate data in 

this implementation guide3

. These data can be used in the reconstruction of 

either internal or external dose, providing that the criteria described in this 

document have been met. In instances, where facility-specific monitoring data 

are sparse, surrogate data can also be used to support the characterization of 

the radiation exposure environment at a facility. 

In practice, surrogate data are most often used by NIOSH in the reconstruction of 

internal doses. This is because a complete exposure model for internal dose 

must not only consider the quantity and composition of the source term, but must 

also predict the plausible levels of airborne contamination that are generated 

from the variety of work processes that occurred at a facility. Later in this 

document, examples of the application of surrogate data to the reconstruction of 

an internal and an external exposure scenario are provided. 

To use surrogate data in the development of an exposure model, certain 

conditions must be met to ensure that the established exposure values 

accurately estimate (or plausibly bound) the exposure conditions at a facility. 

The purpose of this document is to: 1) review the past practices reported in the 

open literature on the use of surrogate data; 2) describe the conditions under 

which surrogate data can be used for conducting dose reconstructions under the 

Energy Employees Occupational Illness Compensation Program Act (EEOICPA); 

and 3) provide examples of the use of such data. 

2.0 PRECEDENCE FOR THE USE OF SURROGATE DATA

2.1 Epidemiologic Studies 

Surrogate data has been used in epidemiological studies to estimate exposure to 

individuals in the workplace. Two previously published review papers provide a 

good summary of the various methods that have been used in reconstructing 

exposures for epidemiological study cohorts (Kauppinen et. al 1994 and Seixas 

et. al 1996). Because the information available for reconstructing chemical and 

physical agent exposures in the workplace has historically been incomplete, a 

number of papers have been published that report on the use of surrogate data 

 

3

 Traditionally, the term “surrogate data” refers to the use of any data that is not a direct measure 

of the individual worker’s exposure conditions (e.g., general air samples or coworker models). In 

this document, however, “surrogate data” is only considered in the context of the use of data from 

another facility. 
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in reconstructing these types of exposures. For example, Hornung, et al. (1994) 

developed a statistical model for the prediction of ethylene oxide exposure that 

was applied to reconstruct exposure in an occupational mortality study. The data 

used in the development of the model were obtained from measurements made 

at 20 different facilities and walk through observations at 36 different plants. 

Another study reported on the development of a model to estimate chemical 

exposures to funeral embalmers using measurements taken at a surrogate test 

facility in which the various parameters that affect exposure could be controlled 

(Stewart et. al 1992). 

Other studies that specifically report on the use of surrogate data for 

reconstructing occupational radiation exposures have been published. In the 

study by Eheman and Tolbert (1999), a job exposure matrix was developed for a 

wide variety of occupations that are potentially externally exposed to radiation. 

For each occupation, a time-dependent log normal probability distribution 

(characterized by a geometric mean and geometric standard deviation) was 

developed that could be used in the reconstruction of individual dose. 

In another publication, involving a comprehensive study of historical exposures to 

radiologic technologists, Simon et al. (2006) used published data from a number 

of medical facilities to establish the distribution of exposures to unmonitored 

technologists. The exposure models developed using these data were used to 

estimate the risk of contracting cancer after exposure to ionizing radiation in the 

workplace. 

2.2 Compensation Programs 

The Radiation Exposure Compensation Act

The use of surrogate data has also been employed in the evaluation of exposure 

in U.S. compensation programs. For example, the evaluation of certain claims 

under the Radiation Exposure Compensation Act (RECA) requires proof of a total 

radon exposure of greater than 40 working level months. If actual radon 

measurements in the mine where a claimant worked are unavailable, RECA 

specifies the following graded approach for evaluating exposure (USDOJ 2004): 

(i) If actual measurements from three or more mines of the same or 

similar type, ventilation, and ore composition are available from the 

mines in the same locality as the mine in which the claimant was 

employed, the average of the exposure levels from mines in the 

same locality will be used. 

(ii) If there are insufficient actual measurements from mines in the 

same locality...an average of the exposure levels in the same 

mining district will be used. 
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(iii) If there is no average of exposure levels from mines in the same 

mining district, the average of exposure levels in the same state will 

be used. 

The Nuclear Test Personnel Review

Another example of the use of surrogate data in a U.S. radiation exposure 

compensation program can be found in the Nuclear Test Personnel Program 

(NTPR) that is administered by the U.S. Department of Veterans Affairs. This 

program covers military personnel who participated in the U.S. nuclear 

atmospheric weapons tests that were conducted from 1945 to 1962. Also 

covered are members of the U.S. military forces who occupied Hiroshima and 

Nagasaki, Japan, after the atomic bombs were dropped in 1945. 

Part of the dose reconstruction for this military cohort requires the reconstruction 

of internal dose due to the inhalation of radioactive particulate. In many 

instances, there are no available bioassay samples or measurements of the 

concentration of radioactivity in air. To reconstruct the inhalation intake of 

radioactive material that deposited on the surface of ships, the NTPR relies on 

the use of resuspension factors that were derived from surrogate data. That is, 

the resuspension factors were developed at a site that performed similar 

operations to those being evaluated under NTPR. 

2.3 General Exposure Modeling 

Knowledge of the extent to which physical parameters and processes affect the 

level of airborne radioactive material in buildings has been used by the U.S. 

Department of Energy to develop exposure models for occupants of a building. 

For example, the RESRAD-BUILD4

 program provides a framework for evaluating 

the dose to an individual who works in a building that is contaminated with 

radioactive material. It allows for the prediction of airborne contamination using 

model input parameters, such as surface contamination levels, building air 

exchanges rates, and resuspension fractions. The bases for many of the 

exposure scenario values used in this program are taken from those reported in 

the literature. Thus, this model relies to a large extent on the use of surrogate 

data. 

3.0 CRITERIA FOR THE USE OF SURROGATE DATA

3.1 Introduction 

In situations where NIOSH lacks personal and/or area monitoring data, the dose 

reconstruction regulation (USHHS 2002, 42 C.F.R. § 82.14 (h)(1) thru (5)) 

 

4

 RESRAD-BUILD – residual radioactivity in a building. 
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provides for the use of source-term and process data to complete 

reconstructions. Specifically, in section 82.2(c), it states: 

If neither adequate worker nor workplace monitoring data are available, 

the dose reconstruction may rely substantially on process description 

information to analytically develop an exposure model. 

Because NIOSH has encountered a number of facilities where radiation 

monitoring data are sparse, models that incorporate non-facility-specific data to 

provide actual or bounding estimates of exposure are necessary to complete 

some dose reconstructions. These models may be needed to reconstruct dose 

for each type of exposure that is evaluated under EEOICPA (i.e., internal, 

external, environmental, and medical). To the extent possible, facility-specific 

data should be used in any dose reconstruction, however, data from other 

facilities should be used when necessary, according to the criteria outlined in this 

Implementation Guide. 

3.2 Source Term 

To model the exposure for a specific process, NIOSH must have, at a minimum, 

knowledge of the types and general quantities of material being processed at the 

facility for which a model is being developed. That is, to some extent the source 

term must be known (USHHS 2002; 42 C.F.R. § 82.14 (h)(1) thru (5)). Section 

83.13 of the Special Exposure Cohort (SEC) rule requires that a dose 

reconstruction must, as a starting point, be based on some information from the 

site where the employee worked (USHHS 2004). For reconstructing exposures, 

this means that some information must be available to identify the radionuclide(s) 

or radiation generating equipment that were present at the facility. 

At Atomic Weapons Employer facilities, where it is more likely that surrogate data 

might be used, the radionuclide dose being reconstructed is most often uranium 

and/or thorium. Thus, if it can be established that the facility processed uranium 

or thorium, the criterion of section 83.13 has been met. Although for practical 

purposes, additional process information would be needed as well. Care must 

be taken, however, to ensure that any disequilibrium in the uranium or thorium 

decay series that is created as a result of chemical processing is taken into 

account in the model. 

3.3 Facility and Process Similarities 

For an exposure model to be sufficiently accurate, it must be based on a process 

that is substantially similar to the one being reconstructed. For example, 

operations that involve grinding, welding, or cutting have a high potential for 

generating airborne particulate and would be inappropriately modeled using data 

from a facility that performed solvent extraction operations. For process-specific 

models, breathing zone air samples are considered the most representative 
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sources of data for modeling inhalation intakes. If breathing zone samples are 

not available, general area air samples may be used, but corrections must be 

made to account for the potential negative bias associated with these types of 

samples. When resuspension models are being developed, it is appropriate to 

rely on general air sample measurements. This is because general area 

samples are less affected by the airborne particulate generated by workplace 

production activities (e.g., grinding, welding, rolling, etc.) 

The physical parameters (e.g., size and ventilation) of the surrogate work area 

must also be considered. How closely the surrogate work area and the area for 

which reconstructions are being performed must match depends to a large extent 

on the types of exposures being evaluated. When attempting to model ambient 

airborne levels in a plant (for example radon levels), care must be taken to relate 

the facilities on size and ventilation rates. This is somewhat less important when 

one is evaluating process-specific breathing zone samples. These samples tend 

to be taken very near the source and are less affected by the facility size and 

general ventilation patterns. These types of samples may, however, be 

influenced by the existence of local capture exhaust ventilation, so care must be 

taken to consider this in model development. 

3.4 Temporal Considerations 

Because building design and processes change over time, it is important to 

consider matching the surrogate facility time period of operation with the facility 

being modeled. If the era of operation of the surrogate facility differs 

substantially from the time period of operation for the facility being modeled, the 

appropriateness of the use of such data should be justified. To the extent 

possible this should be based on the actual recorded conditions at the facilities, 

but input from site subject matter experts can also be used when such 

information are lacking. 

3.5 Data Evaluation 

As with any data used in reconstructing doses, it is important to evaluate the 

quality of the data used in the development of an exposure model. For internal 

exposure models, the methods employed to measure bioassay samples or 

generate air sample results must be evaluated to determine if they were capable 

of detecting the radionuclide being assayed. In addition, the detection limits of 

the method should be considered in the development of the model. If data have 

been censored due to the use of recording or reporting practices (e.g., the 

reporting of zero values or use of less than values that reflect regulatory limits), 

the effect of this practice on the overall usefulness of the data should also be 

evaluated. The overall uncertainty of the model should reflect the uncertainty of 

that data used in its generation. 

3.6 Review of Bounding Exposure Models 
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When a bounding exposure model is developed using surrogate data, the upper 

bound must be plausible. That is, it must be realistically possible given the 

nature of operations at the facility being modeled and other relevant factors. 

While it is not possible to provide fixed criteria for evaluating plausibility, certain 

reasonableness tests can be applied. For example, internal exposures should 

not predict dust loading that would result in asphyxiating conditions, nor should 

external exposure rates produce conditions that would result in acute radiation 

syndrome (unless a criticality event were being modeled or employees 

experienced acute radiation syndrome). Each model should be evaluated for 

plausibility in light of the known conditions in existence at the facility. 

Another test for plausibility might be to compare the exposure values estimated 

by the surrogate model to any facility-specific values that exist for other time 

periods of operation. After taking into consideration differences in plant 

conditions, the predicted values should be evaluated to see if they vary 

substantially (e.g., differences of an order of magnitude or more) from the plantspecific measurements. If large differences are found to exist, efforts should be 

made to determine why the model may or may not be representative of the true 

exposure conditions. 

4.0 EXAMPLES 

4.1 Internal Dose

A common use of surrogate data in the reconstruction of internal dose is the 

evaluation of bounding air concentration values at a facility that worked with 

uranium metal. During the early years of the Atomic Energy Commission’s 

(AEC’s) operations, there were a number of AWE facilities that had contractual 

agreements to conduct forming or shaping work on pieces of uranium metal. 

Because the contracts with a number of these facilities involved short duration 

projects, AEC did not attempt to establish routine radiological monitoring 

programs. 

There exists, however, a significant amount of monitoring data from the uranium 

metal working operations that were engaged in longer-term production activities. 

Further, the equipment at these facilities (e.g., rolling mills, automatic grinding 

machines, lathes, etc.) was substantially similar. If care is exercised in the 

interpretation of the monitoring data available from these facilities, using the 

criteria described in section 3 of this implementation guide, it should be possible 

to develop ranges of air concentrations to which workers were exposed. 

4.2 External Dose 

When a source term and its geometric configuration is known, it is possible to 

model external exposure rates from first principles using knowledge of the 
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inherent radiological properties associated with specific radioactive materials or 

radiation generating devices. Based on this, the external radiation exposure 

rates for various source-terms can be developed using standard Monte Carlo 

based computer codes such as the Los Alamos Monte Carlo N-Particle (MCNP) 

transport code. In certain situations, however, the source terms are not present 

in configurations that easily lend themselves to modeling. This is especially true 

for chemical processing facilities where the radioactive material moves through 

the plant in various chemical forms and degrees of radioactive equilibrium. For 

these types of facilities, it is sometimes possible to bound external exposures 

using the distribution of external doses observed at a facility where a personnel 

monitoring program was in place. In keeping with the requirements of section 3, 

care must be used to ensure that the source term, production rates, and 

processing operations are substantially similar. 

An example where this type of analysis could be employed is in the 

reconstruction of external doses for workers in the phosphate ore processing 

industry. A review of the literature indicates that a fairly extensive evaluation of 

film badge measurements of workers at phosphate plants has been compiled by 

the Florida Institute of Phosphate Research (FIPR). Given that many phosphate 

plants use similar chemical separation processes and equipment, it could be 

possible to bound external exposures at phosphate plants using the distribution 

of data developed by the FIPR. 

5.0 REFERENCES

Eheman, CR and Tolbert, PE (1999). “Estimating occupational radiation doses 

when individual dosimetry is not available: a job exposure matrix,” Amer. J. 

Ind. Med. 36, 348-359. 

Hornung, RW, Greife, AL, Stayner, LT, Steenland, NK, Herrick, RF, Elliott, LJ, 

Ringenburg, VL and Morawetz, J (1994). “Statistical model for prediction of 

retrospective exposure to ethylene oxide in an occupational mortality study,” 

Amer. J. Ind. Med. 25, 825-836. 

Kauppinen, TP (1994). “Assessment of exposure in occupational epidemiology,” 

Scand. J. Work. Environ. Health 20, 19-29. 

Seixas, NS and Checkoway, H (1995). “Exposure assessment in industry specific 

retrospective occupational epidemiology studies,” Occup. Environ. Med. 52, 

625-633. 

Simon, SL, Weinstock, RM, Doody, MM, Neton, J, Wenzl, T, Stewart, P, Mohan, 

AK, Yoder, RC, Hauptmann, M and Linet, M (2006). “Estimating historical 

radiation doses to a cohort of U.S. radiologic technologists,” Radiat. Res. 166, 

174-192. 
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Stewart, PA, Herrick, RF, Feigley, CE, Utterback, DF, Hornung, R, Mahar, H, 

Hayes, R, Douthit, DE and Blair, A (1992). “Study design for assessing 

exposures of embalmers for a case-control study. Part 1. monitoring results,” 

Appl. Occup. Environ. Hyg. 7(8), 532-540. 

U.S. Department of Health and Human Services. Methods for radiation dose 

reconstruction under the Energy Employees Occupational Illness 

Compensation Program Act of 2000, final rule. Washington, DC: U.S. 

Government Printing Office; 42 CFR Part 82; 2002. 

U.S. Department of Health and Human Services. Procedures for designating 

classes of employees as members of the special exposure cohort under the 

Energy Employees Occupational Illness Compensation Program Act of 

2000; final rule. Washington, DC: U.S. Government Printing Office; 42 CFR 

Part 83; 2004. 

U.S. Department of Justice. Claims under the Radiation Exposure Compensation 

Act, Washington, DC: U.S. Government Printing Office; 28 CFR Part 79; 

2004.