[Federal Register Volume 67, Number 85 (Thursday, May 2, 2002)]
[Rules and Regulations]
[Pages 22296-22314]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-10764]



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Part IV





Department of Health and Human Services





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42 CFR Parts 81 and 82



Guidelines for Determining the Probability of Causation and Methods for 
Radiation Dose Reconstruction Under the Employees Occupational Illness 
Compensation Program Act of 2000; Final Rules

  Federal Register / Vol. 67 , No. 85 / Thursday, May 2, 2002 / Rules 
and Regulations  

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DEPARTMENT OF HEALTH AND HUMAN SERVICES

42 CFR Part 81

RIN 0920-ZA01


Guidelines for Determining the Probability of Causation Under the 
Energy Employees Occupational Illness Compensation Program Act of 2000; 
Final Rule

AGENCY: Department of Health and Human Services.

ACTION: Final rule.

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SUMMARY: This rule implements select provisions of the Energy Employees 
Occupational Illness Compensation Program Act of 2000 (``EEOICPA'' or 
``Act''). The Act requires the promulgation of guidelines, in the form 
of regulations, for determining whether an individual with cancer shall 
be found, ``at least as likely as not,'' to have sustained that cancer 
from exposure to ionizing radiation in the performance of duty for 
nuclear weapons production programs of the Department of Energy and its 
predecessor agencies. The guidelines will be applied by the U.S. 
Department of Labor, which is responsible for determining whether to 
award compensation to individuals seeking federal compensation under 
the Act.

DATES: Effective Date: This final rule is effective May 2, 2002.

FOR FURTHER INFORMATION CONTACT: Larry Elliott, Director, Office of 
Compensation Analysis and Support, National Institute for Occupational 
Safety and Health, 4676 Columbia Parkway, MS-R45, Cincinnati, OH 45226, 
Telephone 513-841-4498 (this is not a toll-free number). Information 
requests can also be submitted by e-mail to [email protected]

SUPPLEMENTARY INFORMATION:   

I. Background

A. Statutory Authority

    The Energy Employees Occupational Illness Compensation Program Act 
of 2000(``EEOICPA''), 42 U.S.C. 7384-7385 [1994, supp. 2001], 
established a compensation program to provide a lump sum payment of 
$150,000 and medical benefits as compensation to covered employees 
suffering from designated illnesses (i.e. cancer resulting from 
radiation exposure, chronic beryllium disease, or silicosis) incurred 
as a result of their exposures while in the performance of duty for the 
Department of Energy (``DOE'') and certain of its vendors, contractors, 
and subcontractors. This legislation also provided for payment of 
compensation to certain survivors of covered employees.
    EEOICPA instructed the President to designate one or more federal 
agencies to carry out the compensation program. Pursuant to this 
statutory provision, the President issued Executive Order 13179 titled 
Providing Compensation to America's Nuclear Weapons Workers, which 
assigned primary responsibility for administering the compensation 
program to the Department of Labor (``DOL''). 65 FR 77,487 (Dec. 7, 
2000). DOL published an interim final rule governing its administration 
of EEOICPA on May 25, 2001 (20 CFR Parts 1 and 30).
    The Executive Order directed the Department of Health and Human 
Services (``HHS'') to perform several technical and policymaking roles 
in support of the DOL program:
    (1) HHS is to develop guidelines to be used by DOL to assess the 
likelihood that an employee with cancer developed that cancer as a 
result of exposure to radiation in performing his or her duties at a 
DOE facility or Atomic Weapons Employer (``AWE'') facility. These 
``Probability of Causation'' guidelines are the subject of this final 
rule, and were initially proposed for public comment in a notice of 
proposed rulemaking published on October 5, 2001.
    (2) HHS is also to establish methods to estimate radiation doses 
(``dose reconstruction'') for certain individuals with cancer applying 
for benefits under the DOL program, and HHS is to implement these 
methods in a program of dose reconstruction for EEOICPA claims. HHS 
published these methods as an interim final rule under 42 CFR part 82 
on October 5, 2001, and is publishing them as a final rule 
simultaneously in this issue of the Federal Register. HHS is presently 
applying these methods to conduct the program of dose reconstruction 
required by EEOICPA.
    (3) HHS is to staff the Advisory Board on Radiation and Worker 
Health and provide it with administrative and other necessary support 
services. The Board, a federal advisory committee, was appointed by the 
President in November 2001. It was first convened on January 22, 2001, 
and is advising HHS in implementing its roles under EEOICPA described 
here.
    (4) Finally, HHS is to develop and apply procedures for considering 
petitions by classes of employees at DOE or AWE facilities seeking to 
be added to the Special Exposure Cohort established under EEOICPA. 
Employees included in the Special Exposure Cohort who have a specified 
cancer and meet other conditions, as defined by EEOICPA and DOL 
regulations (20 CFR 30), qualify for compensation under EEOICPA. HHS 
has developed proposed procedures for considering Special Exposure 
Cohort petitions which will be published soon in the Federal Register. 
HHS will obtain public comment and a review by the Advisory Board on 
Radiation and Worker Health before these procedures are made final and 
implemented.
    As provided for under 42 U.S.C. 7384p, HHS is implementing its 
responsibilities with the assistance of the National Institute for 
Occupational Safety and Health (``NIOSH''), an institute of the Centers 
for Disease Control and Prevention, HHS.

B. Purpose of Probability of Causation Guidelines

    Under EEOICPA, a covered employee seeking compensation for cancer, 
other than as a member of the Special Exposure Cohort seeking 
compensation for a specified cancer, is eligible for compensation only 
if DOL determines that the cancer was ``at least as likely as not'' (a 
50% or greater probability) caused by radiation doses incurred in the 
performance of duty while working for DOE and/or an atomic weapons 
employer (AWE) facility. These guidelines provide DOL with the 
procedure to make these determinations, and specify the information DOL 
will use.
    HHS notes that EEOICPA does not authorize the establishment of new 
radiation protection standards through the promulgation of these 
guidelines, and these guidelines do not constitute such new standards.

C. Statutory Requirements for Probability of Causation Guidelines

    EEOICPA has several general requirements concerning the development 
of these guidelines. It requires the guidelines provide for 
determinations that are based on the radiation dose received by the 
employee, incorporating the methods of dose reconstruction to be 
established by HHS. It requires determinations be based on the upper 99 
percent confidence interval of the probability of causation in the 
radioepidemiological tables published under section 7(b) of the Orphan 
Drug Act (42 U.S.C. 241 note), as such tables may be updated. EEOICPA 
also requires HHS to consider the type of cancer, past health-related 
activities, the risk of developing a radiation-related cancer from 
workplace exposure, and other relevant factors. 42 U.S.C. 7384n(c). It 
is also important to

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note EEOICPA does not include a requirement limiting the types of 
cancers to be considered radiogenic for these guidelines.

D. Understanding Probability of Causation

    Probability of Causation is a technical term generally meaning an 
estimate of the percentage of cases of illness caused by a health 
hazard among a group of persons exposed to the hazard. This estimate is 
used in compensation programs as an estimate of the probability or 
likelihood that the illness of an individual member of that group was 
caused by exposure to the health hazard. Other terms for this concept 
include ``assigned share'' and ``attributable risk percent'.
    In this rule, the potential hazard is ionizing radiation to which 
U.S. nuclear weapons workers were exposed in the performance of duty; 
the illnesses are specific types of cancer. The probability of 
causation (PC) is calculated as the risk of cancer attributable to 
radiation exposure (RadRisk) divided by the sum of the baseline risk of 
cancer to the general population (BasRisk) plus the risk attributable 
to the radiation exposure, then multiplied by 100 percent, as follows:
[GRAPHIC] [TIFF OMITTED] TR02MY02.011

This calculation provides a percentage estimate between 0 and 100 
percent, where 0 would mean 0 likelihood that radiation caused the 
cancer and 100 would mean 100 percent certainty that radiation caused 
the cancer.
    Scientists evaluate the likelihood that radiation caused cancer in 
a worker by using medical and scientific knowledge about the 
relationship between specific types and levels of radiation dose and 
the frequency of cancers in exposed populations. Simply explained, if 
research determines that a specific type of cancer occurs more 
frequently among a population exposed to a higher level of radiation 
than a comparable population (a population with less radiation exposure 
but similar in age, gender, and other factors that have a role in 
health), and if the radiation exposure levels are known in the two 
populations, then it is possible to estimate the proportion of cancers 
in the exposed population that may have been caused by a given level of 
radiation.
    If scientists consider this research sufficient and of reasonable 
quality, they can then translate the findings into a series of 
mathematical equations that estimate how much the risk of cancer in a 
population would increase as the dose of radiation incurred by that 
population increases. The series of equations, known as a dose-response 
or quantitative risk assessment model, may also take into account other 
health factors potentially related to cancer risk, such as gender, 
smoking history, age at exposure (to radiation), and time since 
exposure. The risk models can then be applied as an imperfect but 
reasonable approach to determine the likelihood that the cancer of an 
individual worker was caused by his or her radiation dose.

E. Development and Use of the RadioEpidemiological Tables and 
Interactive RadioEpidemiological Program

    In 1985, in response to a congressional mandate in the Orphan Drug 
Act, a panel established by the National Institutes of Health developed 
a set of Radioepidemiological Tables. The tables serve as a reference 
tool providing probability of causation estimates for individuals with 
cancer who were exposed to ionizing radiation. Use of the tables 
requires information about the person's dose, gender, age at exposure, 
date of cancer diagnosis and other relevant factors. The tables are 
used by the Department of Veterans Affairs (DVA) to make compensation 
decisions for veterans with cancer who were exposed in the performance 
of duty to radiation from atomic weapon detonations.
    The primary source of data for the 1985 tables is research on 
cancer-related deaths occurring among Japanese atomic bomb survivors 
from World War II.
    The 1985 tables are presently being updated by the National Cancer 
Institute (NCI) and the Centers for Disease Control and 
Prevention1 to incorporate progress in research on the 
relationship between radiation and cancer risk. The draft update has 
been reviewed by the National Research Council 2 and by 
NIOSH. DOL will employ the updated version of the tables, with 
modifications important to claims under EEOICPA (described below under 
``G'' and in response to public comments under ``II''), as a basis for 
determining probability of causation for employees covered under 
EEOICPA.
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    \1\ Draft Report of the NCI-CDC Working Group to Revise the 1985 
NIH Radioepidemiological Tables, May 31, 2000.
    \2\ A Review of the Draft Report of the NCI-CDC Working Group to 
Revise the ``1985 Radioepidemiological Tables'', National Research 
Council.
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    A major scientific change achieved by this update is the use of 
risk models developed from data on the occurrence of cancers (cases of 
illness) rather than the occurrence of cancer deaths among Japanese 
atomic bomb survivors. The risk models are further improved by being 
based on more current data as well. Many more cancers have been modeled 
in the revised report. The new risk models also take into account 
factors that modify the effect of radiation on cancer, related to the 
type of radiation dose, the amount of dose, and the timing of the dose.
    A major technological change accompanying this update, which 
represents a scientific improvement, is the production of a computer 
software program for calculating probability of causation. This 
software program, named the Interactive RadioEpidemiological Program 
(IREP), allows the user to apply the NCI risk models directly to data 
on an individual employee. This makes it possible to estimate 
probability of causation using better quantitative methods than could 
be incorporated into printed tables. In particular, IREP allows the 
user to take into account uncertainty concerning the information being 
used to estimate probability of causation. There typically is 
uncertainty about the radiation dose levels to which a person has been 
exposed, as well as uncertainty relating levels of dose received to 
levels of cancer risk observed in study populations.
    Accounting for uncertainty is important because it can have a large 
effect on the probability of causation estimates. DVA, in their use of 
the 1985 Radioepidemiological Tables, uses the probability of causation 
estimates found in the tables at the upper 99 percent credibility 
limit. This means when DVA determines whether the cancer of a veteran 
was more likely than not caused by radiation, they use the estimate 
that is 99 percent certain to be greater than the probability that 
would be calculated if the information on dose and the risk model were 
perfectly accurate. Similarly, these HHS guidelines, as required by 
EEOICPA, will use the upper 99 percent credibility limit to determine 
whether the cancers of employees are at least as likely as not caused 
by their occupational radiation doses. 42 U.S.C. 7384n(c)(3)(A). This 
will help minimize the possibility of denying compensation to claimants 
under EEOICPA for those employees with cancers likely to have been 
caused by occupational radiation exposures.

F. Use of IREP for Energy Employees

    The risk models developed by NCI and CDC for IREP provide the 
primary basis for developing guidelines for estimating probability of 
causation under EEOICPA. They directly address 33 cancers and most 
types of radiation

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exposure relevant to employees covered by EEOICPA. These models take 
into account the employee's cancer type, year of birth, year of cancer 
diagnosis, and exposure information such as years of exposure, as well 
as the dose received from gamma radiation, x rays, alpha radiation, 
beta radiation, and neutrons during each year. Also, the risk model for 
lung cancer takes into account smoking history and the risk model for 
skin cancer takes into account race/ethnicity. None of the risk models 
explicitly accounts for exposure to other occupational, environmental, 
or dietary carcinogens. Models accounting for these factors have not 
been developed and may not be possible to develop based on existing 
research. Moreover, DOL could not consistently or efficiently obtain 
the data required to make use of such models.
    IREP models do not specifically include cancers as defined in their 
early stages: carcinoma in situ (CIS). These lesions are becoming more 
frequently diagnosed, as the use of cancer screening tools, such as 
mammography, have increased in the general population. The risk factors 
and treatment for CIS are frequently similar to those for malignant 
neoplasms, and, while controversial, there is growing evidence that CIS 
represents the earliest detectable phase of malignancy.3 
Therefore, for determining compensation under EEOICPA, HHS requires 
that CIS be treated as a malignant neoplasm of the specified site.
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    \3\ Kerlikowske, K, J Barclay, D Grady, EA Sickles, and V 
Ernster. ``Comparison of risk factors for ductal carcinoma in situ 
and invasive breast cancer.'' J. Natl. Canc. Inst. 89:76-82, 1997.
    Grippo, PJ, and EP Sandgren. ``Highly invasive transitional cell 
carcinoma of the bladder in a simian virus 40 T-antigen transgenic 
mouse model.'' Am. J. Pathol. 157:805-813, 2000.
    Correa P, ``Morphology and natural history of cancer 
precursors'' Chapter 4 in: Cancer Epidemiology and Prevention, 2nd 
Edition, D Schottenfeld and JF Fraumeni, Jr, eds. New York: Oxford 
University Press, 1996.
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    Cancers identified by their secondary sites (sites to which a 
malignant cancer has spread), when the primary site is unknown, raise 
another issue for the application of IREP. This situation will most 
commonly arise when death certificate information is the primary source 
of a cancer diagnosis. It is accepted in medicine that cancer-causing 
agents such as ionizing radiation produce primary cancers. This means, 
in a case in which the primary site of cancer is unknown, the primary 
site must be established by inference to estimate probability of 
causation.
    HHS establishes such assignments in these guidelines, based on an 
evaluation of the relationship between primary and secondary cancer 
sites using the National Center for Health Statistics (NCHS) Mortality 
Database for years 1995-1997. Because national cancer incidence 
databases (e.g., the National Cancer Institute's Surveillance, 
Epidemiology and End Results program) do not contain information about 
sites of metastasis, the NCHS database is the best available data 
source at this time to assign the primary site(s) most likely to have 
caused the spread of cancer to a known secondary site. For each 
secondary cancer, HHS identified the set of primary cancers producing 
approximately 75% of that secondary cancer among the U.S. population 
(males and females were considered separately). The sets are tabulated 
in this rule (Table 1). DOL will determine the final assignment of a 
primary cancer site for an individual claim on a case-by-case basis, as 
the site among possible primary sites which results in the highest 
probability of causation estimate.
    Employees diagnosed with two or more primary cancers also raise a 
special issue for determining probability of causation. Even under the 
assumption that the biological mechanisms by which each cancer is 
caused are unrelated, uncertainty estimates about the level of 
radiation delivered to each cancer site will be related. While fully 
understanding this situation requires statistical training, the 
consequence has simple but important implications. Under this rule, 
instead of determining the probability that each cancer was caused by 
radiation independently, DOL will perform an additional statistical 
procedure following the use of IREP to determine the probability that 
at least one of the cancers was caused by the radiation. This approach 
is important to the claimant because it would determine a higher 
probability of causation than would be determined for either cancer 
individually.

G. Limitations of IREP for Energy Employees

    NCI is developing IREP to serve the needs of DVA in deciding cancer 
compensation claims for veterans. This means IREP has to be adapted in 
various ways to meet the needs of DOL, because the radiation exposure 
experience of employees covered by EEOICPA differs substantially.
    Some employees covered by EEOICPA were exposed to radon and other 
sources of high linear energy transfer (LET) radiation. This type of 
radiation exposure has unique properties affecting cancer risk, which 
are not addressed in the risk models included in IREP. Specifically, 
the IREP risk models do not account for a possible inverse dose-rate 
effect for high-LET radiation exposures. This effect means at any 
particular dose level, especially higher dose levels, a dose of high 
LET radiation incurred gradually over time is more likely to cause 
cancer than the same total dose incurred quickly or at once. A 
substantial body of research supports this finding, including studies 
of uranium miners,4 patients exposed to bone-seeking radium 
alpha particles,5 and research on the cancer effects of high 
LET radiation in animals.6 Because high-LET radiation is an 
important type of radiation exposure among employees covered by 
EEOICPA, NIOSH has modified IREP to include uncertainty associated with 
the assumption of an inverse dose-rate effect for these exposures.
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    \4\ Hornung RW, Meinhardt TJ. Quantitative risk assessment of 
lung cancer in U.S. uranium miners. Health Phys 52: 417-430, 1987.
    Lubin JH, Boice JD Jr, Edling C, et al. Radon-exposed 
underground miners and the inverse dose-rate (protraction 
enhancement) effects. Health Phys 69:494-550, 1995.
    \5\ Mays CW, Spiess H. Bone sarcomas in patients given radium-
224. In: Radiation Carcinogenesis: Epidemiology and Biological 
Significance. Boice JD Jr, Fraumeni JF Jr (eds): New York: Raven 
Press, pp 241-252, 1984.
    \6\ Luebeck EG, Curtis SB, Cross FT, Moolgavkar SH. Two-stage 
model of radon-induced malignant lung tumors in rats: effects of 
cell killing. Radiat. Res. 145:163-173, 1996.
    Hall EJ, Miller RC, Brenner DJ. Neoplastic transformation and 
the inverse dose-rate effect for neutrons. Radiat. Res. 128 (Suppl): 
S75-S80, 1991.
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    The DOE workforce has been exposed to various types of neutron 
energies and these exposures are frequently documented in the worker's 
dosimetry records. The relative biological effectiveness (RBE) of 
radiation exposure, a factor in cancer risk models that accounts for 
the differing level of cancer risk associated with different forms of 
radiation, varies as a function of neutron energy.7 This 
variation in RBE related to differing neutron energy is not accounted 
for in the current version of IREP, which contains a single neutron RBE 
distribution. Therefore, NIOSH has modified IREP for DOE workers to 
include different RBE distributions for neutrons of various energies.
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    \7\ International Commission on Radiological Protection (ICRP) 
60: ``1990 Recommendations of the International Commission on 
Radiological Protection.'' Ann. ICRP 21 (1-3): 1-201.
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    The currently public draft of IREP does not incorporate a unique 
lung cancer model for radon exposure, which is an important exposure 
for some workers covered under EEOICPA. Using epidemiologic evidence on 
the lung carcinogenicity of radon exposures, NCI

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has incorporated a lung cancer model for radon exposures into IREP. The 
data source for this model is the analysis conducted by the federal 
Radiation Exposure Compensation Act Committee.8
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    \8\ Final Report of the Radiation Exposure Compensation Act 
Committee, submitted to the Human Radiation Interagency Working 
Group, July 1996 (Appendix A), 30 pp (plus Figures).
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    NIOSH has changed IREP to modify an assumption for non-leukemia 
cancers that low-level acute radiation doses (defined in IREP as doses 
between 3 and 30 cSv) cause less risk, per unit of dose, than higher 
level acute doses. NIOSH will use an uncertainty distribution for the 
dose and dose rate effectiveness factor (DDREF) that more heavily 
weights a DDREF of one, reducing the distinction in risk effects for 
low-level acute doses. A recent study of the Japanese atomic bomb 
survivors supports this change.9
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    \9\ Pierce DA and Preston DL ``Radiation-related cancer risks at 
low doses among atomic bomb survivors.'' Radiat. Res. 154:178-186, 
2000.
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    Additionally, some employees covered by EEOICPA were required, as a 
condition of employment, to undergo routine medical screening with x 
rays. The dose resulting from these x rays will be included in their 
dose reconstruction. This required NIOSH to add to IREP an RBE 
distribution appropriate to the low-energy form of radiation produced 
from some of these x rays. 10
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    \10\ ICRU Report 40: The quality factor in radiation protection. 
Internat. Commission on Radiat. Units and Meas., 33 pp, 1986.
    Hall EJ. ``Linear energy transfer and relative biological 
effectiveness'' Chapter 9 in Radiobiology for the Radiobiologist, 
4th Edition. Philadelphia: J.B. Lippincott, 1994.
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    Research has found bone cancer risk substantially and significantly 
elevated among animals and humans exposed to certain forms of high-LET 
radiation. 11 Although Japanese A-bomb survivor risk models 
for bone cancer have been used for a plutonium risk assessment, 
12 they are based on highly unstable risk models. Therefore, 
NIOSH is using in IREP the risk model recommended in the NCI-IREP 
documentation, which is based on all residual cancers, including bone.
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    \11\ International Agency for Research on Cancer (IARC). IARC 
Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 
78 Ionizing Radiation, Part 2: Some Internally Deposited 
Radionuclides. Lyon, France: IARC Press, 595 pp, 2001.
    \12\ Grogan HA, Sinclair WK, and Voilleque PG. ``Risks of fatal 
cancer from inhalation of 239,240plutonium by humans: a combined 
four-method approach with uncertainty evaluation'' Health Physics 
80:447-461, 2001.
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    Limitations of current research and development have prevented 
NIOSH from considering and implementing all possible improvements to 
IREP at this time. In the future, NIOSH may make additional changes in 
IREP to address differences in radiation-related cancer risk between 
Japanese atomic bomb survivors and employees involved in nuclear 
weapons production. Some research has shown substantial differences in 
risk for certain cancers, such as brain cancer and multiple myeloma 
13. The radiation-related risk of these cancers is 
significantly elevated among employees involved in nuclear weapons 
production, whereas it is not among the Japanese study population. The 
IREP risk models for these cancers were produced using data from the 
Japanese study population.
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    \13\ Alexander V and DiMarco JH. ``Reappraisal of brain tumor 
risk among U.S. nuclear workers: a 10-year review.'' Occupational 
Medicine: State of the Art Reviews 16(2):289-315, 2001.
    Cardis E, Gilbert ES, Carpenter L, et al. ``Effects of low doses 
and low dose rates of external ionizing radiation: cancer mortality 
among nuclear industry workers in three countries.'' Radiat. Res. 
142:117-132, 1995.
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    Similarly, it may be possible to improve the fit of IREP risk 
models to employees covered by EEOICPA with respect to differences 
between the frequency of certain cancers in the general population in 
the United States versus Japan. The IREP risk models include a 
simplistically derived factor (risk transfer) that accounts for these 
differences, based on expert judgment. For some cancers, such as breast 
and stomach cancer, sufficient research may exist to improve this 
factor. In addition, where current IREP risk models could be replaced 
with risk models based on studies of U.S. DOE workers, or other U.S. 
populations, this factor could be omitted entirely. The potential 
future use of risk models based on studies of U.S. DOE workers may also 
eliminate limitations arising because data are sparse for certain 
cancers among the Japanese atomic bomb survivors, such as most specific 
types of leukemia. Using data on the Japanese cohort, the effect on 
risk of age at time of exposure to radiation, an important modifier of 
leukemia risk, cannot be estimated for specific types of leukemia, 
except chronic myeloid leukemia. It can only be estimated for other 
leukemia types by using a general leukemia model that combines data 
from cases of different types of leukemia.
    Finally, NIOSH may make modifications in cancer risk models in 
IREP, as appropriate and if feasible, to account for the changing 
frequency among the general population (baseline rates) of certain 
types of cancer in the United States. Certain types of cancer (e.g., 
lung cancer among women, breast cancer) have become more frequent in 
recent decades. Similarly, NIOSH may make modifications in cancer risk 
models to reflect the differing frequency of certain types of cancer 
among different racial and ethnic groups in the United States (e.g., 
multiple myeloma). The effect of these modifications, at such time as 
they may become available, would be to improve the accuracy of 
probability of causation estimates.

H. Procedures for Review and Public Comment on NIOSH-IREP

    As described under Section G above, some current and potential 
future changes to the cancer risk models in IREP are particularly 
appropriate for addressing the radiation exposures and statutory 
requirements of claimants under EEOICPA. As a result, the version of 
IREP to include NIOSH modifications will be unique and distinguished as 
``NIOSH-IREP.'' This version, which DOL will use to estimate 
probability of causation under EEOICPA, will be reviewed by the 
Advisory Board on Radiation and Worker Health. NIOSH-IREP is available 
for public review on the NIOSH homepage at: www.cdc.gov/niosh/ocas/ocasirep/html. It includes documentation of underlying risk models and 
calculations. The public can obtain complete information about NIOSH-
IREP by contacting NIOSH at its toll-free telephone information 
service: 1-800-35-NIOSH (1-800-356-4674).
    The public may comment on NIOSH-IREP at any time. Comments can be 
submitted by e-mail to [email protected], or by mailing written comments to: 
NIOSH-IREP Comments, National Institute for Occupational Safety and 
Health, 4676 Columbia Parkway, MS-R45, Cincinnati, Ohio 45226. All 
comments will be considered. In addition, NIOSH will forward all 
substantive comments to the Advisory Board on Radiation and Worker 
Health, which will have an ongoing role to review and advise NIOSH on 
possible changes to NIOSH-IREP, as described in this rule.

I. Operating Guide for NIOSH-IREP

    DOL will use procedures specified in the NIOSH-IREP Operating Guide 
to calculate probability of causation estimates under EEOICPA. The 
guide provides current, step-by-step instructions for the operation of 
NIOSH-IREP. The procedures include entering personal, diagnostic, and 
exposure data; setting/confirming appropriate values for variables used 
in calculations; conducting the calculation; and, obtaining, 
evaluating, and reporting results.

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    An initial version of the NIOSH-IREP Operating Guide is available 
to the public online on the NIOSH homepage at: www.cdc.gov/niosh/ocas/ocasirep/html. The public can obtain printed copies by contacting NIOSH 
at its toll-free telephone information service: 1-800-35-NIOSH (1-800-
356-4674).

II. Summary of Public Comments

    On October 5, 2001, HHS proposed guidelines for determining 
probability of causation under EEOICPA (42 CFR 81; see 66 FR 50967). 
HHS initially solicited public comments from October 5 to December 4, 
2001. The public comment period was reopened subsequently from January 
17, 2002 to January 23, 2002 for public comments, and from January 17, 
2002 to February 6, 2002, for comments from the Advisory Board on 
Radiation and Worker Health (67 FR 2397).
    HHS received comments from 12 organizations and 24 individuals. 
Organizations commenting included several labor unions representing DOE 
workers, a community based organization, an administrative office of 
the University of California, several DOE contractors, and several 
federal agencies. A summary of these comments and HHS responses is 
provided below. These are organized by general topical area.

A. Appropriateness of Adapting Compensation Policy Used for Atomic 
Veterans

    One commenter requested explanation of the appropriateness of 
adapting existing compensation policy for atomic veterans to a 
compensation program for nuclear weapons workers. The comment appears 
to question whether this existing policy for atomic veterans is an 
appropriate starting point from which to develop compensation policy 
under EEOICPA. In the notice of proposed rulemaking, HHS had solicited 
public comment on whether it had appropriately adapted compensation 
policy for atomic veterans to meet the needs of this workforce, which 
has a substantially different occupational and radiation exposure 
experience.
    Congress determined the veteran's compensation policy as a starting 
point for HHS. It did so by requiring the determination of probability 
of causation based on radiation doses and the use of the NIH 
Radioepidemiological Tables, and by requiring that the cancer covered 
in a claim be determined to be ``at least as likely as not'' caused by 
radiation doses incurred in the performance of duty, based on the upper 
99 percent credibility limit. These are defining features of 
compensation policy for atomic veterans.
    The public should also recognize that the Radioepidemiological 
Tables required years to initially develop and then additional years to 
update (the update is not completed). Without this critical, highly 
sophisticated element developed for the veterans' program, it would not 
have been possible to establish and implement a policy for nuclear 
weapons workers in a timely fashion.
    HHS adapted these policies for nuclear weapons workers through two 
prominent measures, discussed in the notice of proposed rulemaking and 
below. HHS included provisions to allow NIOSH to adapt the cancer risk 
models in the latest version of the NIH Radioepidemiological Tables to 
reflect the unique radiation exposure experience of nuclear weapons 
workers. And HHS established transparent, objective procedures for DOL 
to handle a variety of circumstances in which various information 
relevant to determining probability of causation will be unknown. The 
majority of comments received on this rule suggest most commenters view 
as appropriate the measures HHS has taken to adapt existing 
compensation policy to this new program.

B. Compensability

    Various comments relating to the use of these guidelines were 
received. Specifically, HHS received comments on: awarding compensation 
based upon a proportional level of probability of causation; the use of 
the upper 99 percent confidence limit to estimate probability of 
causation; awarding compensation for employees who incurred radiation 
doses within regulated radiation safety limits; automatically 
qualifying employees who incurred doses in excess of the maximum 
allowable radiation dose under Atomic Energy Commission regulations; 
waiving dose reconstruction and probability of causation for employees 
with rare cancers; and automatically compensating employees for whom 
DOE is unwilling or unable to provide employment records.
    The development and use of these guidelines for determining 
compensability and the benefit structure are statutorily mandated and 
therefore these comments were not adopted.
    One commenter suggested prohibiting the use of probability of 
causation findings as proof of fault in litigation. This suggestion was 
not adopted because prohibiting the use of probability of causation 
findings for litigation purposes is not authorized by the statute. 
However, because these findings will be based on NIOSH dose 
reconstructions, which will not always produce complete or best 
estimates of the actual doses received by an individual,14 
HHS does not believe these findings should be used for any purpose 
other than the adjudication of claims under EEOICPA.
---------------------------------------------------------------------------

    \14\ For explanation of these possible limitations of NIOSH dose 
reconstructions, see the discussion under ``II. Summary of Public 
Comments; A. Purpose of the Rule'' in the preamble of 42 CFR Part 82 
(the HHS dose reconstruction rule).
---------------------------------------------------------------------------

C. Need for Peer Review

    Several commenters recommended that HHS obtain peer review of the 
cancer risk models that comprise NIOSH-IREP, and of changes to NIOSH-
IREP, as it is updated based on progress in the underlying sciences. 
Several commenters recognized that the Advisory Board on Radiation and 
Worker Health is intended by HHS as one means of obtaining such peer 
review, but the commenters raised concerns about whether the Board 
would have sufficient expertise for this purpose.
    HHS recognizes the importance of peer review. Consequently, as 
indicated above, the National Cancer Institute obtained peer review of 
IREP by the National Research Council. NCI and NIOSH have made 
modifications in IREP consistent with this peer review. NIOSH has also 
obtained peer-review by independent subject matter experts of changes 
developed by NIOSH to adapt IREP to the experience of nuclear weapons 
workers. These peer-reviews are posted on the NIOSH website and are 
also available to the public by request.
    In addition, the Advisory Board on Radiation and Worker Health will 
be reviewing the cancer risk models in NIOSH-IREP, as indicated above 
and in the notice of proposed rulemaking. Contrary to the public 
comments noted above, HHS finds the Board has appropriate expertise for 
such a review, including eminent physicians and scientists from the 
field of health physics. Moreover, the Board maintains the option to 
commission additional independent scientists to participate in the 
Board's review. HHS also has the option to obtain additional peer 
reviews by the National Academy of Sciences, as recommended by some 
commenters.
    In response to comments recommending peer review and to the 
recommendations of the Advisory Board on Radiation and Worker Health 
discussed below, HHS has added a new requirement to this rule to affirm 
the commitment of HHS to involve the

[[Page 22301]]

Board in peer-review of future decisions to change NIOSH-IREP and to 
ensure this process is open to public participation. These provisions, 
which were previously contained in the preamble of the notice of 
proposed rulemaking, are now incorporated into the rule itself under 
Sec. 81.12.
    One commenter recommended HHS extend the comment period of the rule 
to provide the public with additional time to review NIOSH-IREP.
    As indicated in the notice of proposed rulemaking and above, the 
public can comment on NIOSH-IREP at any time. The rule comment period 
applies only to provisions of the rule itself.

D. Updating NIOSH-IREP to Remain Current With Science

    Commenters supported the intent of HHS to update NIOSH-IREP as 
scientific progress enables HHS to improve the cancer risk models. Two 
commenters recommended that DOL apply updates to NIOSH-IREP 
retrospectively to claims that were denied on the basis of a 
probability of causation finding that might change as a result of the 
update.
    Under 42 CFR 81.12 NIOSH will notify the public and DOL when 
changes to NIOSH-IREP are completed and explain the effect of changes 
on probability of causation estimates. This will enable DOL and 
claimants with denied claims to identify denied claims potentially 
affected by the changes and evaluate the effect of this new 
information.

E. Chemical or Non-Occupational Radiation Exposures as Risk Factors

    Some nuclear weapons workers were exposed to potential and known 
chemical carcinogens as well as radiation in the performance of duty. 
Several commenters urged that cancer risk models in NIOSH-IREP take 
into account the effects that these combined or ``mixed'' exposures 
might have on risk associated with radiation exposure.
    There is no adjustment in NIOSH-IREP for chemical exposures. It is 
not clear that the state of science presently could support risk 
adjustments that account for possibly differing roles of chemical 
exposures. A second, probably overriding, practical concern is whether 
this compensation program for nuclear weapons workers, which already 
requires the collection and consideration of large amounts of 
information, could produce fair, timely decisions with the addition of 
a substantial new informational burden. New information would be 
required for each claim regarding the type, level, duration, and timing 
of relevant chemical exposures, as well as the use of administrative 
measures and protective equipment to protect exposed workers.
    Despite these limitations, NIOSH will consider taking into account 
the effect of mixed exposures at such time as this may become 
scientifically supportable and feasible. HHS has added section 
81.10(b)(4) to specifically include this possibility.
    Several other commenters made similar but distinct recommendations 
to modify the cancer risk models in NIOSH-IREP to account for cancer 
risks that might be independent of radiation risks, arising from 
occupational and community exposures to chemicals or non-occupational 
exposures to radiation. Some commonplace examples of such exposures 
might include exposures to solvents or preservatives used at work or 
home, radon in the home, second-hand tobacco smoke, or sun exposure. 
The recommendation relates to the fact that groups have different 
``background'' risks of cancers depending on their exposure to these 
various carcinogens. Groups with higher than normal background risks 
might be shown in studies of radiation risks to have lower increases in 
cancer risk attributable to radiation. Likewise, groups with lower than 
normal background risks might be shown to have higher increases in risk 
attributable to radiation, depending on the form of interaction between 
radiation exposures and these other cancer risk factors.
    It is not scientifically supportable or feasible to adjust NIOSH-
IREP risk models for the multitude of occupational and community 
exposures. The carcinogenic risks associated with most chemical 
exposures, and the appropriate form of their interaction with 
radiation, have not been adequately quantified. Moreover, DOL generally 
would not have access to exposure data on the individual's exposure to 
chemicals or radiation in the community. As discussed above, access to 
data on occupational exposures to chemicals is also infeasible at this 
time.

F. Covered Exposures

    A few commenters recommended changes in the set of exposures 
included by this rule to contribute to the probability of causation 
calculation.
    Several commenters recommended against HHS including medical 
screening x rays administered to nuclear weapons employees as a 
condition of employment. Similar comments were received on the interim 
final HHS dose reconstruction rule (42 CFR 82) as well. Commenters 
argue that the benefit of these exposures justifies their attendant 
risks, and therefore they should not contribute to the acceptance of a 
claim for compensation.
    HHS will not exclude radiation exposures resulting from these 
occupationally required medical screening x rays. The important factor 
in this decision is that the exposures were incurred ``in the 
performance of duty,'' as specified by EEOICPA. The employees were 
required to receive these x ray screenings and hence were exposed to 
radiation in performing this duty.
    Several commenters recommended HHS include cancer risks associated 
with chemical exposures and in effect calculate a probability of 
causation related to all occupational exposures, rather than radiation 
exposures alone.
    HHS cannot include the cancer risks associated with chemical 
exposures in the calculation of probability of causation. EEOICPA 
explicitly limits these guidelines and DOL to making determinations as 
to whether the cancer subject to a claim was caused by radiation doses 
incurred in the performance of duty (see Sec. 7384(n)(c) of EEOICPA).

G. Covered Illnesses

    HHS received several comments addressing the exclusion or inclusion 
of illnesses covered by these guidelines.
    Several commenters noted that EEOICPA only covers cancers but 
should cover other or all illnesses. A second commenter recommended 
that probability of causation should be determined for inherited 
genetic effects (among offspring of covered workers).
    The probability of causation guidelines cover only cancers because 
this is a statutory requirement of EEOICPA (see discussion of statutory 
requirements above). Moreover, science has not progressed sufficiently 
to permit probability of causation determinations for many radiogenic 
illnesses other than cancers; specifically not for inherited genetic 
effects.
    Readers should note, however, that part B of EEOICPA, which 
provides lump sum payments of $150,000 as well as medical benefits, 
provides coverage for chronic beryllium disease and silicosis (when 
incurred by workers exposed in connection with mining of tunnels for 
atomic weapons tests or experiments in Nevada or Alaska), two well 
documented occupational illnesses. Part B also provides for medical 
monitoring of covered workers with beryllium sensitivity. In addition, 
part D of EEOICPA provides assistance through a worker advocacy program 
administered by DOE to assist nuclear

[[Page 22302]]

weapons workers with illnesses that might have resulted from toxic 
occupational exposures who are seeking state workers' compensation 
benefits. Panels of expert physicians appointed by HHS will review the 
medical records in connection with each of these cases and make a 
determination as to whether the illness was likely to have been caused 
by toxic occupational exposures.
    Another commenter recommended that HHS not permit probability of 
causation to be determined for cancers in situ--that is, cancers that 
have yet to spread to neighboring tissues. In other words, the comment 
recommends assigning a probability of causation of zero to individuals 
with this early stage of cancer.
    HHS is retaining the procedures it proposed for estimating 
probability of causation for carcinomas in situ, treating them within 
NIOSH-IREP identically to invasive cancers. Although more research is 
needed, some studies have shown the risk factors for a carcinoma in 
situ are similar to cancer at a later stage. In addition, for any given 
individual, it is not possible to determine which carcinomas in situ 
will progress to become invasive cancers.

H. Radiation Dose Threshold for Calculating Probability of Causation

    Several commenters recommended HHS establish a radiation dose 
threshold below which DOL would deny the claim without calculating 
probability of causation. One commenter proposed NIOSH-IREP be modified 
to take into account alternative theories of radiation effects at low 
cumulative doses. The commenters argue that it is unknown whether 
cancers can be caused at radiation doses below 10 to 20 rem. In 
addition, several commenters note that claims for rare cancers, for 
which there is likely to be a high level of uncertainty about the dose-
risk relationship, would have unfair advantage over claims for more 
common cancers, due to the use of the 99 percent credibility limit.
    The National Research Council, which reviewed IREP, noted concern 
about the effect of uncertainty with respect to rare cancers. NCI has 
responded to this concern by grouping rare cancers in more general 
cancer categories, for which there is a more robust research basis for 
quantifying risk.
    HHS does not find that any further measures are necessary, 
particularly the application of a threshold. The issue of whether or 
not there is a threshold for causation of cancer by radiation is 
controversial. Moreover, the issue is avoided by the practical approach 
taken in this rule. Doses resulting in a probability of causation 
finding of 50 percent or greater are determined based on current and 
cumulative epidemiologic findings. The NCI solution of grouping rare 
cancers addresses the concern about high levels of uncertainty for rare 
cancers.

I. Non-Radiogenic Cancers

    One commenter recommended against the proposed rule's consideration 
of chronic lymphocytic leukemia (CLL) as non-radiogenic (Sec. 81.30). 
This provision requires DOL to assign a probability of causation of 
zero for a claim for CLL. The commenter asserts that it cannot be 
proven that this form of leukemia is non-radiogenic.
    As discussed in the notice of proposed rulemaking and below, CLL is 
widely considered non-radiogenic by the radiation health research 
community and is not covered by other radiation compensation programs. 
Moreover, there is no risk model appropriate to CLL, nor data to 
support the development of such a risk model. Consequently, it is not 
possible to calculate probability of causation for CLL and it is both 
appropriate and necessary to consider CLL as non-radiogenic for the 
purposes of this rule.

J. Documentation of NIOSH-IREP

    Several commenters recommended NIOSH fully document the risk models 
and calculations of NIOSH-IREP so that the basis for its calculations 
are fully transparent. One commenter added that in this documentation, 
NIOSH should explain how different sources of uncertainty are taken 
into account.
    NIOSH agrees with the comment and, as indicated in the notice of 
proposed rulemaking, is committed to maintaining and providing full 
documentation on NIOSH-IREP. To a substantial extent, this 
documentation is directly available to the public while using or 
examining NIOSH-IREP. The software, which is accessible for public use 
from the NIOSH homepage on the internet, has a feature that allows the 
user to call-up the formulae and information underlying each 
calculation. The user can also call-up graphic illustrations (pie 
charts) that quantitatively depict the role of different sources of 
uncertainty in contributing to the overall uncertainty calculated for 
use in a probability of causation estimate.15 As noted 
above, the documentation is also available in print form by contacting 
NIOSH.
---------------------------------------------------------------------------

    \15\ The uncertainty distributions for the various sources of 
uncertainty involved in a probability of causation estimate are 
combined in NIOSH-IREP using a Monte Carlo simulation program that 
draws values randomly, repeatedly from each distribution to derive a 
single, representative uncertainty distribution.
---------------------------------------------------------------------------

K. Current Technical Elements of NIOSH-IREP

    HHS received a variety of comments on specific aspects of the 
cancer risk models in NIOSH-IREP. While these risk models are not 
themselves subject to this rulemaking, HHS is committed to receiving 
and responding to public comments on NIOSH-IREP, and making 
improvements as appropriate. As indicated in Sec. 81.12 of this rule, 
recommendations for modifications to NIOSH-IREP will be addressed 
routinely through a public process involving the Advisory Board on 
Radiation and Worker Health. Hence, HHS addresses current comments 
submitted during the rulemaking comment period below, but notes that 
some of these issues may receive further consideration subsequent to 
this rulemaking, once HHS has obtained advice on these issues by the 
Advisory Board. The Advisory Board has received these public comments 
for review.
    One commenter generically recommended against making use in NIOSH-
IREP of cancer risk models developed for determining probability of 
causation for atomic veterans. As discussed above and in the notice of 
proposed rulemaking, most of the risk models in IREP were developed 
based on the exposure and disease experience of Japanese survivors of 
the atomic bomb detonations in World War II. The commenter finds the 
differences between the exposure conditions of these survivors and 
those of nuclear weapons employees too great to support probability of 
causation determinations for the latter.
    HHS recognizes the substantial differences between the radiation 
exposure experiences of these two populations and discussed these 
differences above and in the notice of proposed rulemaking. To address 
these differences, NIOSH has adapted the available risk models to the 
extent feasible and supportable using current science. The difference 
in exposure characteristics is also part of the rationale for the 
provisions of this rule supporting updates of NIOSH-IREP, as scientific 
progress allows additional improvements. One of the specified goals of 
such updates is to use, as this becomes feasible, risk findings derived 
from occupational health studies of nuclear weapons workers.
    Nonetheless, NIOSH maintains that the current scientific basis 
applied in

[[Page 22303]]

NIOSH-IREP is the best available at this time and that its use is both 
reasonable and fair. As discussed throughout this rule, NIOSH has taken 
into account, whenever feasible, recognized limitations in the current 
state of relevant sciences.
    Several commenters recommended changes in the way the lung cancer 
risk model adjusts risk according to the individual's smoking history. 
The risk model produces a higher probability of causation that lung 
cancer was caused by radiation for a non-smoker than a smoker, at a 
given level and pattern of radiation exposure.
    One commenter indicated that the probability of causation estimate 
for a heavy smoker should be much lower than currently estimated by the 
risk model. The other commenters recommended the opposite, that NIOSH 
should eliminate adjustment for smoking history. They assert research 
indicates that smoking may have a multiplicative effect on lung cancer 
risk, when combined with radiation exposure. If this research were 
proven correct, then smoking history would not affect the contribution 
of radiation to cancer risk, and could indeed be omitted from 
consideration.
    The adjustment for smoking history in NIOSH-IREP has been adopted 
from the approach developed by NCI, and fully takes into account the 
cumulative body of research evaluating the interaction between smoking 
and radiation risks, as well as leading scientific views on this 
research. The NCI review of relevant literature, and a scientific 
consensus panel opinion (UNSCEAR 200016), conclude that the 
best-supported risk models to evaluate the form of interaction between 
smoking and radiation are based on meta-analyses of radon-exposed 
workers. Combined analyses of these studies suggest that the most 
appropriate form of interaction is sub-multiplicative (i.e., the excess 
relative risk from radiation exposure among smokers is less than the 
excess relative risk among non-smokers), but greater than additive 
(Lubin and Steindorf 1995). NCI used this scientific basis to develop 
an uncertainty distribution for the form of interaction between smoking 
and radiation in the lung cancer risk models that is centered on a sub-
multiplicative model (i.e., a model which assumes the excess relative 
risk of cancer per unit of radiation dose is lower for individuals who 
smoke more), but includes the possibility of either a multiplicative 
model (i.e., that excess relative risk per unit of radiation dose is 
the same for various levels of smoking, including non-smokers) or a 
super-multiplicative model (i.e., that excess relative risk per unit 
dose is higher for individuals who smoke more). As with all 
assumptions, this uncertainty distribution is subject to modification 
in future revisions of NIOSH-IREP, pending the availability of new 
scientific information.
---------------------------------------------------------------------------

    \16\ United National Scientific Committee on the Effects of 
Atomic Radiation. 2000. Sources and Effects of Ionizing Radiation: 
UNSCEAR 2000 Report to the General Assembly, with Scientific 
Annexes, Volume II: Effects; p. 201-203.
    Lubin JH and Steindorf K. 1995. Cigarette use and the estimation 
of lung cancer attributable to radon in the United States. Radiat. 
Res. 141:79-85.
---------------------------------------------------------------------------

    Several commenters recommended against use of a factor that reduces 
cancer risk for workers who were exposed to radiation at older ages. In 
support of this recommendation, they contend atomic bomb survivor and 
occupational studies do not find an inverse relationship for adults 
between age at time of radiation exposure and cancer risk.
    NIOSH is using in NIOSH-IREP the NCI approach to adjusting 
radiation risk estimates for different exposure ages. This approach is 
based on new epidemiological analyses of atomic bomb survivors who were 
of working age when exposed during the blast, and uses an approach 
recommended by an international expert committee (Pierce et al. 1993, 
UNSCEAR 2000 17). It addresses all solid cancers except skin 
and thyroid. Thus, for most cancers NIOSH-IREP relies on direct 
evidence from the A-bomb survivors exposed as adults rather than as 
children. NCI did not incorporate any age at exposure effect for the 
following cancers: acute myeloid leukemia, chronic myeloid leukemia, 
lung cancer (non-radon exposures), and female genital cancers other 
than ovary. The NCI models do incorporate a trend of decreasing risk 
per unit dose with increasing age at exposure for the following cancer 
sites: acute lymphocytic leukemia, all leukemia other than chronic 
lymphocytic, basal cell carcinoma, and cancers of thyroid. For radon 
exposures and lung cancer, there is no direct adjustment for exposure 
age: risks are dependent on time since last exposure and on age at 
diagnosis. The effect of this adjustment is that, at a constant ``time 
since last exposure'', the risk decreases for increasing age at last 
exposure; however, for constant ``age at diagnosis'', the risk 
increases for increasing age at last exposure. For all other cancers, 
the NCI models incorporate a trend of decreasing risk per unit dose for 
exposure ages between 15 and 30, and assume constancy (no effect of 
age) thereafter.
---------------------------------------------------------------------------

    \17\ Pierce DA, Preston DL. 1993. Joint analysis of site-
specific cancer risks for the A-bomb survivors. Radiat. Res. 
137:134-142.
    United National Scientific Committee on the Effects of Atomic 
Radiation. 2000. Sources and Effects of Ionizing Radiation: UNSCEAR 
2000 Report to the General Assembly, with Scientific Annexes, Volume 
II: Effects; p. 208.
---------------------------------------------------------------------------

    There is substantial evidence from several key studies in addition 
to those of the A-bomb cohort that suggests radiation risk for many 
cancers decreases with increasing age at exposure. These include 
studies of breast cancer among x-ray tuberculosis patients (Boice et 
al. 1991 18), of thyroid cancer among medically- and 
occupationally-exposed populations (summarized in UNSCEAR 2000a3), and 
of skin cancer (UNSCEAR 2000b3). While some studies of DOE workers 
suggest no effect or find increased relative risk estimates for certain 
cancers from exposure to radiation at older ages, this information is 
insufficient to support the selection of appropriate cancers and an 
appropriate method for quantitatively incorporating this information 
into risk adjustments in NIOSH-IREP. As indicated in the rule, HHS will 
re-evaluate this issue in future revisions of NIOSH-IREP, as warranted 
by advances in scientific information.
---------------------------------------------------------------------------

    \18\ Lubin JH, Boice JD Jr, Edling C, et al. 1995. Lung cancer 
risk in radon-exposed miners and estimation of risk from indoor 
exposure. J. Natl. Canc. Inst. 87:817-827.
    Boice JD Jr, Engholm G, Kleinerman RA, et al. 1991. Frequent 
chest x-ray fluoroscopy and breast cancer incidence among 
tuberculosis patients in Massachusetts. Radiat. Res. 125:214-222.
    United National Scientific Committee on the Effects of Atomic 
Radiation. 2000a. Sources and Effects of Ionizing Radiation: UNSCEAR 
2000 Report to the General Assembly, with Scientific Annexes, Volume 
II: Effects; p. 338-343.
    United National Scientific Committee on the Effects of Atomic 
Radiation. 2000b. Sources and Effects of Ionizing Radiation: UNSCEAR 
2000 Report to the General Assembly, with Scientific Annexes, Volume 
II: Effects; p. 402.
    Richardson DB, Wing S, Hoffmann W. 2001. Cancer risk from low-
level ionizing radiation: the role of age at exposure. Occupat. 
Med.: State of the Art Reviews 16:191-218.
---------------------------------------------------------------------------

    Several commenters recommended adding a risk adjustment factor to 
NIOSH-IREP to account for a possible ``healthy survivor effect'' 
presently unaccounted for in the research on Japanese atomic bomb 
survivors. The theory underlying this comment is that atomic bomb 
survivors may be healthier than the general public and less likely to 
incur cancer. Therefore, according to this theory, it would be mistaken 
to equate the level of increased cancer risk from radiation among this 
robustly healthy population to the level of increased cancer risk among 
the U.S. population, with its normal distribution of health. If this 
were proven correct, the risk models in NIOSH-IREP should

[[Page 22304]]

be adjusted to increase the level of cancer risk caused by a unit of 
radiation dose, since the U.S. population would presumably be more 
susceptible than the Japanese survivor population to the cancer-causing 
effects of radiation.
    The possible existence of a healthy survivor effect has been 
theorized by some researchers (Stewart and Kneale 199019), 
and has been determined by others to be of small magnitude or non-
existent (Little and Charles 1990, NCRP 1997). The NCI determined that 
insufficient information on the possible effect of this bias is 
available for use the IREP program. NIOSH, in consultation with the 
Advisory Board on Radiation and Worker Health, will consider whether to 
add an adjustment factor to future versions of NIOSH-IREP to account 
for a possible healthy survivor effect, if supported by new scientific 
information. HHS notes such a finding would be equally relevant for 
claimants under EEOICPA and under the Atomic Veterans Compensation 
Program, and thus should be decided by scientific consensus between 
these two programs whose relevant policies are both determined by HHS.
---------------------------------------------------------------------------

    \19\ Stewart AM, and Kneale GW. 1990. A-bomb radiation and 
evidence of late effects other than cancer. Health Phys. 58:729-735.
    Little MP, and Charles MW. 1990. Bomb survivor selection and 
consequences for estimates of population cancer risks. Health Phys. 
59:765-775.
    National Council on Radiation Protection and Measurements 
(NCRP). 1997. Uncertainties in fatal cancer risk estimates used in 
radiation protection. NCRP report 126. 112 pp.
---------------------------------------------------------------------------

    Several commenters recommended changing the factor in NIOSH-IREP 
that reduces cancer risk for workers who were exposed to low linear 
energy transfer (LET) 20 radiation at low dose rates 
(workers who received many small doses of radiation, versus fewer large 
doses). They cite reports by the Nuclear Regulatory Commission and the 
International Agency for Research on Cancer as finding no relationship 
between the rate at which low LET radiation doses are incurred and the 
risk of cancer.
---------------------------------------------------------------------------

    \20\ See Sec. 81.4 in rule for a definition of LET.
---------------------------------------------------------------------------

    HHS agrees that this is an area of substantial uncertainty. Many 
studies suggest that risks are reduced for particular cancers when 
doses are fractionated or received at low dose-rate, while other 
studies suggest no effect of dose-rate or dose fractionation on 
radiation risk.
    NIOSH-IREP accounts for this uncertainty. For chronic exposures, 
NIOSH-IREP adopts the approach used in the final revision of the NCI-
IREP program, which more heavily weights a probability that there is no 
attenuation of risk at low dose rates of exposure. This uncertainty 
distribution also includes a small probability that dose-rate reduction 
or dose fractionation enhances, rather than reduces, radiation risk.
    One commenter recommends that NIOSH-IREP account for a possible 
inverse relationship between exposure to low doses of high LET 
radiation and cancer risk. The commenter cites recent research 
suggesting that individuals who incurred high LET radiation doses at 
lower rates had higher risk of cancer, compared with individuals who 
incurred the same cumulative doses at higher rates.
    As indicated in the notice of proposed rulemaking and above, NIOSH 
has incorporated the possibility of this inverse relationship into 
NIOSH-IREP for both neutron and low-LET exposures. Based on reviews of 
subject matter experts, the revised version of NIOSH-IREP includes a 
small probability of an inverse dose-rate effect for alpha radiation 
exposures as well.
    One commenter noted that a linear-quadratic model of the dose-risk 
relationship is not equivalent to use of a dose-rate correction factor 
to reduce the per-unit contribution of low doses to cumulative risk of 
cancer. The commenter recommended either using a dose-rate correction 
factor to keep these model elements separate, or alternatively to 
explain why it is appropriate to use the linear-quadratic model to 
mimic a reduced cancer risk effect at low dose rates.
    This comment is contradicted by several research groups, including 
the NCI-IREP working group, the NIH Ad Hoc Working Group which 
initially developed the Radioepidemiological Tables (NIH 1985 
21), and the Committee on Biological Effects of Ionizing 
Radiation (BEIR)V. The BEIR V committee explicitly states that ``[Dose 
rate] reductions should be applied only to the non-leukemia risks, as 
the leukemia risks already contain an implicit DREF [dose rate 
effectiveness factor] owing to the use of the linear-quadratic model'' 
22. The theoretical basis for this equivalence is the 
observation that the use of a linear-quadratic dose assumption applies 
a reduction in risk that is equivalent to using a dose-and-dose-rate 
reduction factor of about two, which has been commonly recommended by 
advisory groups for modeling leukemia risk.
---------------------------------------------------------------------------

    \21\ National Institutes of Health (NIH). 1985. Report of the 
National Institutes of Health Ad Hoc Working Group to Develop 
Radioepidemiological Tables. US DHHS. NIH Publication No. 85-2748, 
p. 88.
    \22\ National Research Council. 1990. Health Effects of Exposure 
to Low Levels of Ionizing Radiation: BEIR V. National Academy Press, 
Washington, DC. 421 pp., p.174.
---------------------------------------------------------------------------

    One commenter recommended NIOSH change the dose and dose rate 
effectiveness factor (DDREF) for leukemia (for low LET radiation 
exposure) to three. This would reduce by two-thirds the probability of 
causation estimates for workers with leukemia who accrued their 
cumulative radiation doses slowly. The commenter cites two studies to 
support this recommendation.
    NIOSH-IREP uses the models developed by the NCI Working Group for 
leukemia risk from low-LET exposure. As discussed previously, rather 
than incorporating a DDREF of greater than one for leukemia risk 
models, the dose-response function for leukemia is of the linear-
quadratic form. This corresponds approximately to a DDREF of two for 
leukemia risk at low compared to high doses and dose rates. This 
approach has been recommended by several expert committees, referenced 
above.6, 7 While findings from individual 
epidemiological studies may vary from this approach, these individual 
study findings are subject to the limitations of the studies. For this 
reason, risk modeling requires consideration of the totality of 
scientific evidence regarding the effects of dose protraction. 
Consistent with the extensive expert analyses cited above, NIOSH-IREP 
uses a linear-quadratic model with uncertainty in the model parameters, 
which best captures the uncertainties associated with the effects at 
low doses and dose rates.
    One commenter recommends NIOSH obtain peer review for the radiation 
weighting factors used in NIOSH-IREP. These weighting factors take into 
account the differing biological effect potency of different types of 
radiation in inducing cancer. The commenter states that a factor of 40 
used for alpha radiation in NIOSH-IREP, that this is ``too 
conservative'' (i.e., results in probability of causation estimates 
that would be higher than scientifically justified), and notes that the 
International Commission on Radiological Protection (ICRP) intends to 
lower its recommended weight for alpha radiation from 20 to 10.
    The commenter misunderstands how information on the biological 
effectiveness of radiation types is used in NIOSH-IREP. The ICRP and 
other leading expert groups recommend weighting factors in the form of 
point estimates to summarize the differing biological effectiveness of 
various types of radiation for use by radiation protection programs. 
These programs

[[Page 22305]]

require a point estimate to calculate appropriate safety criteria that 
can be applied to protect populations. On the other hand, the task 
involving NIOSH-IREP is to calculate probability of causation for 
individual claims, taking into account sources of scientific 
uncertainty. There is substantial uncertainty of science in describing 
the biological effectiveness of various types of radiation, and in part 
due to this uncertainty, there are differences in the review findings 
of ICRP, the International Commission on Radiation Units and 
Measurements, and the National Council on Radiation Protection and 
Measurements. In addition, some radiation exposures are incompletely 
addressed by the reviews by these expert groups.
    To evaluate scientific uncertainty, NIOSH analyzed the reviews of 
biological effectiveness of radiation by each of the expert committees 
cited above and, where these reviews were incomplete, other expert 
reviews and primary research as well. Based on this analysis, NIOSH 
established the central tendency of ``relative biological 
effectiveness'' for each type of radiation and assigned a probability 
distribution to describe the scientific uncertainty about the central 
tendency estimate. To calculate probability of causation, NIOSH-IREP 
will apply these resulting uncertainty distributions derived by NIOSH, 
instead of point estimate weighting factors, to account for the 
differing biological effectiveness of various radiation types.
    The NIOSH analysis of relative biological effectiveness described 
here has been summarized in a scientific paper, peer-reviewed by 
subject matter experts, and revised accordingly. It is available to the 
public, along with the peer-review comments, from the NIOSH homepage on 
the internet or by direct request to NIOSH (addresses provided above) 
23.
---------------------------------------------------------------------------

    \23\ The paper was originally titled: ``Proposed Radiation 
Weighting Factors for Use in Calculating Probability of Causation 
for Cancers'' and is now published with revisions and more extensive 
explanation under the title: ``Relative Biological Effectiveness 
Factors (RBE) for Use in Calculating Probability of Causation of 
Radiogenic Cancers.''
---------------------------------------------------------------------------

    One commenter questions how the lung cancer model for radon in 
NIOSH-IREP compares with the recommendations of the Committee on Health 
Risks of Exposure to Radon (BEIR VI) 24.
---------------------------------------------------------------------------

    \24\ National Research Council. 1999. Health Effects of Exposure 
to Radon: BEIR VI. National Academy Press, Washington, DC. 500 pp.
---------------------------------------------------------------------------

    As discussed in the notice of proposed rulemaking and above, the 
lung cancer model for radon in NIOSH-IREP was developed based on an 
analysis of risk by the Radiation Exposure Compensation Act (RECA) 
Committee 25, as recommended by the National Research 
Council review of the NCI IREP software. The RECA committee recommended 
scientific methods for adapting the radon and lung cancer risk models 
derived from uranium miner research to compensation decisions. These 
research findings were an important component of the BEIR VI analyses 
as well.
---------------------------------------------------------------------------

    \25\ Final Report of the Radiation Exposure Compensation Act 
Committee, submitted to the Human Radiation Interagency Working 
Group, July 1996 (Appendix A), 30 pp (plus Figures).
---------------------------------------------------------------------------

L. HHS Dose Reconstruction Program (42 CFR 82)

    HHS received several comments addressed to this rule that relate to 
HHS dose reconstructions under EEOICPA. In some cases, the comments 
were directed to this rule because dose reconstruction results serve as 
inputs to calculate probability of causation. The HHS rule establishing 
methods for dose reconstruction, 42 CFR Part 82, is being published 
simultaneously in this issue of the Federal Register.
    Several commenters recommended that these guidelines prescribe the 
selection of uncertainty distributions associated with radiation dose 
information supplied by the NIOSH dose reconstruction.
    As discussed in the dose reconstruction rule, uncertainty 
distributions associated with the dose information will indeed be 
defined by NIOSH in its individual dose reconstruction final reports 
provided to DOL, the claimant, and DOE. This information, also included 
in the electronic dose files provided to DOL by NIOSH, will be imported 
into NIOSH-IREP by DOL when it calculates probability of causation.
    These uncertainty distributions associated with dose information 
cannot be generically prescribed by these guidelines. This information 
will vary substantially depending on radiation exposure circumstances 
and informational sources associated with each claim. Therefore, NIOSH 
will be defining the use of appropriate uncertainty distributions on a 
claim-by-claim basis, based on technical procedures established by 
NIOSH to implement the HHS dose reconstruction rule.
    One commenter recommended NIOSH use a default assumption that 
characterizes radiation doses as chronic rather than acute. The 
commenter indicated that the radiation doses incurred by many workers 
are more accurately characterized as chronic using traditional 
definitions.
    NIOSH will characterize radiation doses as chronic when it has 
information to substantiate this designation. However, in most cases 
NIOSH is unlikely to have sufficient information to make this 
distinction. For these cases, NIOSH will continue to characterize doses 
as acute as the default assumption, since this gives claimants the 
benefit of the doubt. As discussed above, this rule, consistent with 
the requirement of EEOICPA to calculate probability of causation at the 
upper 99 percent credibility limit, gives claimants the benefit of the 
doubt with respect to uncertainty. The use of chronic as a default 
assumption would reduce the level of probability of causation 
calculated for some claims.
    One commenter recommended NIOSH-IREP include as an input radiation 
doses from nuclides (types of radiation) associated with particle 
accelerators.
    The radiation weighting factors included in NIOSH-IREP cover the 
vast majority of exposures that have occurred or will occur in the 
claimant population. Exposures to the most unusual radiation exposure 
types, such as protons and other accelerator produced particles, will 
be addressed on an individual basis, as specified by NIOSH. It would 
not be useful to construct a priori probability distributions for these 
radiation types without knowledge of the range of energies likely to be 
involved in an actual exposure. Probability distributions developed for 
these unusual radiation types will be incorporated into the probability 
of causation calculation for affected claimants by DOL through a user-
definable feature of NIOSH-IREP. NIOSH will define the probability 
distribution to be applied by DOL and summarize its technical basis in 
the dose reconstruction report.
    One commenter questioned how NIOSH would know the energies of 
neutron doses, since this information will not always be available from 
DOE or AWE records.
    As discussed in the interim final and final dose reconstruction 
rules, NIOSH will assign the energies for claims in which this specific 
information is unknown. NIOSH will give the benefit of the doubt to the 
claimant in making such assignments, such that the energy selected is 
consistent with available information and represents the case most 
favorable to the claimant for calculating probability of causation.

[[Page 22306]]

    One commenter recommended that NIOSH combine the internal and 
external dose reconstruction data into single annual dose values.
    It is unclear how this suggested change would be useful. Moreover, 
it would rarely be feasible. It would be feasible only when radiation 
doses in a given year are limited to a single type of radiation and the 
uncertainty distributions for the external and internal doses are 
identical.
    Several commenters questioned why HHS added a parameter to the 
definition of ``covered employee,'' under Sec. 81.4 of the proposed 
rule, that is not specified in EEOICPA. HHS specified more narrowly 
than EEOICPA that a covered employee, for the purposes of the HHS 
rules, is a DOE or AWE employee for whom DOL has requested HHS perform 
a dose reconstruction.
    This distinction results practically from the separate 
responsibilities of DOL and HHS in implementing EEOICPA. DOL is solely 
responsible for initially reviewing each claim, evaluating whether the 
claim represents a covered employee with a covered illness, and 
determining whether or not the claim requires a dose reconstruction. 
The only claims DOL will forward to HHS for dose reconstructions are 
those involving a covered employee with a cancer not covered by 
provisions of the Special Exposure Cohort. Hence, HHS retains its 
proposed definition in this rule to be clear that NIOSH will only 
conduct dose reconstructions under EEOICPA for the subset of claims 
submitted by DOL to HHS for dose reconstructions. This is intended to 
avoid the possible confusion and delay that would arise if claimants or 
the public were to directly submit to NIOSH requests for dose 
reconstructions.

M. Special Exposure Cohort

    HHS received several comments that provide recommendations, 
criteria, or concerns related to adding members to the Special Exposure 
Cohort established under EEOICPA. These comments fall outside the scope 
of this rule and address related but separate procedures to be 
established by HHS.
    As discussed above, HHS is proposing procedures by which it will 
consider petitions by classes of employees at DOE or AWE facilities to 
be added to the cohort, with the advice of the Advisory Board on 
Radiation and Worker Health. These procedures will be published soon in 
the Federal Register. The proposed HHS procedures and their 
accompanying explanation address the comments received and directly 
solicit additional public comments, which HHS will fully consider in 
establishing final procedures.

N. DOL Responsibilities Under EEOICPA

    HHS received several comments that relate to DOL responsibilities 
under EEOICPA and thus fall outside the scope of this rule.
    One commenter recommended that claimants be provided with full 
documentation of the basis for the probability of causation estimate 
determined for their claim by DOL.
    DOL will provide the claimant with a recommended decision which 
will explain the decision based upon the probability of causation. In 
addition, NIOSH will provide the claimant with complete documentation 
on the dose reconstruction conducted for the claim, which, together 
with the DOL report, provides the claimant with a complete set of the 
claim-related data and information used to calculate probability of 
causation.
    The claimant would not, however, automatically receive 
documentation of the formulae and underlying research basis for the 
cancer risk models applied to the claim in NIOSH-IREP. This information 
is highly technical and complex and is unlikely to be of value to most 
claimants. Claimants who desire this information, however, can obtain 
it either from NIOSH-IREP, from the NIOSH homepage, or by contacting 
NIOSH directly (see contact information above). Some details of IREP 
documentation are only available at this time from NCI but will be 
incorporated into NIOSH informational resources as soon as possible.
    One commenter recommended that claimants be permitted to submit 
affidavits in lieu of medical records when necessary.
    DOL determines what types of information can constitute medical 
evidence of a diagnosis of cancer (see 20 CFR 30.211.). More details 
can be obtained by contacting DOL.
    One commenter recommended that staff working for contractor support 
services offsite from the DOE facility should be treated as covered 
employees under EEOICPA. The comment identifies workers providing 
offsite laundry services as an example of such support staff. As 
discussed above, DOL is responsible for determining whether an 
individual is a covered employee within the scope of coverage defined 
by Congress in EEOICPA. Individuals who are concerned that certain 
employee groups involved in nuclear weapons production or related 
activities might be excluded from coverage under EEOICPA should consult 
DOL, which makes these determinations.

III. Review and Recommendations of the Advisory Board on Radiation 
and Worker Health

    As discussed above, the Advisory Board on Radiation and Worker 
Health is required by Section 7384(n)(c) of EEOICPA to conduct a 
technical review of these HHS guidelines. The Board reviewed the 
guidelines during public meetings on January 22-23 and February 5, 
2002. In preparation for the meeting, the Board members individually 
reviewed the notice of proposed rulemaking as well as the HHS interim 
final rule providing the methods of dose reconstruction (42 CFR 82) 
that govern the estimation of radiation doses to be used under these 
guidelines. The members also reviewed public comments on these rules 
and written comments by subject matter experts who evaluated technical 
elements of NIOSH-IREP. In addition, NIOSH staff members gave formal 
presentations on the HHS rules, implementation procedures, and related 
issues during the Board meetings. The transcripts and minutes of these 
meetings are included in the NIOSH docket for this rule and are 
available to the public.
    All of the Board members participated in the technical review of 
these guidelines and they unanimously concurred in establishing the 
Board findings and recommendations. The Board organized its findings 
and recommendations to correspond with the three general questions for 
public comment HHS identified in the notice for proposed rulemaking. 
The findings and recommendations are provided below, together with 
responses by HHS to the recommendations:
    Board Comment #1: The Board agrees that the NIOSH guidelines and 
procedures for probability of causation determinations have been 
developed using the best and most current scientific information 
relating radiation exposures to cancer risks. The use of current 
recommendations from independent expert bodies lends strength to the 
approach proposed by NIOSH. The NIOSH approach also implements the 
spirit of concern for nuclear workers that was inherent in the 
legislation underlying this compensation program. In this context, the 
NIOSH guidelines and procedures provide an appropriate application of 
existing science to the compensation process.
    HHS Response: No response is necessary, but it may be helpful to 
readers to explain the Board's reference to the ``spirit of concern.'' 
HHS has

[[Page 22307]]

implemented the ``spirit of concern'' to which the Board refers by 
consistently and reasonably giving the benefit of the doubt to nuclear 
weapons workers, whenever feasible, with respect to policy decisions 
and technical procedures involving factual or scientific unknowns and 
uncertainty.
    Board Comment #2: ``The Board has also noted the differences 
between the approach being used in this compensation program and that 
of the Atomic Veterans Act. There are significant differences in the 
categories of compensation covered by the two acts. In some cases, the 
Atomic Veterans Act required primarily that the claimants were present 
in a specific area, had one of the specified cancers, and were 
therefore compensated. This proposed rule is an effort to address much 
more complicated situations and to face the reality that simple 
exposure to radiation does not automatically presume the development of 
disease. The Board recognizes the excellent efforts of NIOSH staff and 
their subject matter experts in bringing the best known current science 
to an appropriate method for translating experience gained in the 
veterans exposure calculations to this civilian nuclear worker 
proposal.''
    HHS Response: No response necessary.
    Board Comment #3: ``The Board also agrees that the proposed NIOSH 
procedures appropriately allow for the incorporation of new scientific 
information into the compensation procedures as this new information 
becomes available. However, given the limited time that the Board has 
had to review the details of the probability of causation procedures 
and the potential impact of changes in the NIOSH IREP on compensation 
decisions, the Board recommends that the regulations be amended to 
formalize the role of the Board in reviewing any substantial changes in 
these procedures (i.e., the NIOSH IREP). This change should include 
publication of the planned changes in the Federal Register, an 
appropriate opportunity for public comment, and then review by this 
Board before finalization. Although these actions are included in the 
Preamble ``Background,'' (Section III, Subsection I, Paragraph 3) of 42 
CFR Part 81, making them part of the rule itself would formalize the 
updating process, significantly strengthening assurance that review of 
revisions by the Board will occur.''
    HHS Response: HHS accepts this recommendation by the Board. 
Accordingly, as discussed above in response to public comments on peer-
review, HHS has moved provisions for peer-review involving the Board 
from the preamble of the notice of proposed rulemaking into the body of 
the rule itself. These provisions can be found at 42 CFR 81.12.

IV. Summary of the Rule

    Congress, in enacting EEOICPA, created a new Energy Employees 
Occupational Illness Compensation Program to ensure an efficient, 
uniform, and adequate compensation system for certain employees. 
Through Executive Order 13179, the President assigned primary 
responsibility for administering the program to DOL. The President 
assigned various technical responsibilities for policymaking and 
assistance to HHS. Included among these is promulgation of this rule to 
establish guidelines DOL will apply to adjudicate cancer claims for 
covered employees seeking compensation for cancer, other than as 
members of the Special Exposure Cohort seeking compensation for a 
specified cancer. Sections 81.20-81.25 and 81.30 provide guidelines for 
determining the probability of causation with respect to all known 
cancers.
    In the summary below, HHS indicates all the changes in provisions 
of this rule made since the notice of proposed rulemaking. These occur 
under Secs. 81.10(b) and 81.12.

Introduction

    Sections 81.0 and 81.1 briefly describe how this rule relates to 
DOL authorities under EEOICPA and the assignment of authority for this 
rule to HHS. Section 81.2 summarizes the specific provisions of EEOICPA 
directing HHS in the development of this rule.

Definitions

    This section of the regulation defines the principal terms used in 
this part. It includes terms specifically defined in EEOICPA that, for 
the convenience of the reader of this part, are repeated in this 
section. The citation to EEOICPA has been revised to reflect the 
codification of the Act in the United States Code.

Data Required To Estimate Probability of Causation

    Sections 81.5 and 81.6 identify the sources and types of personal, 
medical, and radiation dose information that would be required by this 
regulation. Claimants will provide personal and medical information to 
DOL under DOL regulations 20 CFR Part 30. NIOSH will provide radiation 
dose information pursuant to 20 CFR Part 30. NIOSH will develop the 
dose information required pursuant to the HHS regulation under 42 CFR 
Part 82, which was promulgated on October 5, 2001 as an interim final 
rule and is being promulgated as a final rule simultaneously with this 
final rule in this issue of the Federal Register. The application of 
this personal, medical, and radiation dose information to estimate 
probability of causation is described generally under Secs. 81.22--
81.25.

Requirements for Risk Models Used To Estimate Probability of Causation

    Sections 81.10 and 81.11 describe the use of cancer risk models and 
uncertainty analysis underlying the NIH RadioEpidemiological Tables in 
their current, updated form, which is a software program named the 
``Interactive RadioEpidemiological Program'' (IREP). NIOSH-IREP, the 
version of IREP to be used by DOL to implement this rule, is discussed 
extensively in the notice of proposed rulemaking and above. These 
sections also propose criteria by which the risk models in NIOSH-IREP 
may be changed to ensure that probability of causation estimates 
calculated for EEOICPA claimants represent the unique exposure and 
disease experiences of employees covered by EEOICPA. In response to 
public comments, a criterion discussed above has been added to 
Sec. 81.10. This criterion authorizes NIOSH to modify NIOSH-IREP to 
account for new understanding of the potential interaction between 
cancer risks associated with occupational exposures to chemical 
carcinogens and radiation-related cancer effects (see 
Sec. 81.10(b)(4)).
    Section 81.12 was added in response to comments and describes the 
procedure to update NIOSH-IREP. NIOSH may periodically revise NIOSH-
IREP to add, modify, or replace cancer risk models, improve the 
modeling of uncertainty, and improve the functionality and user-
interface of NIOSH-IREP. Principal sources of potential improvements in 
cancer risk models include new epidemiologic research on DOE employee 
populations and periodic updates from scientific committees evaluating 
such research (e.g., the Committee on Biological Effects of Ionizing 
Radiation).
    Improvements may also be recommended by the Advisory Board on 
Radiation and Worker Health, scientific reviews relevant to or 
addressing this program, public comment, or by DOL, which is the 
principal user and hence may require functional changes and 
improvements in the user-interface.
    Substantive changes to NIOSH-IREP (changes that would substantially 
affect

[[Page 22308]]

estimates of probability of causation calculated using NIOSH-IREP, 
including the addition of new cancer risk models) will be submitted to 
the Advisory Board on Radiation and Worker Health for review. Proposed 
changes provided to the Advisory Board for review will also be made 
available to the public, which will have opportunity to comment and 
have its comments considered by NIOSH and the Board.
    To facilitate public participation in updating NIOSH-IREP, NIOSH 
will periodically publish a notice in the Federal Register informing 
the public of proposed substantive changes to NIOSH-IREP currently 
under development, the status of the proposed changes, and the expected 
completion dates. NIOSH will also publish a notice in the Federal 
Register notifying DOL and the public of the completion of substantive 
changes to NIOSH-IREP. In the notice, NIOSH will address relevant 
public comments and recommendations from the Advisory Board received by 
NIOSH.

Guidelines To Estimate Probability of Causation

    Sections 81.20 and 81.21 require DOL to use NIOSH-IREP to estimate 
probability of causation for cancers for which probability of causation 
estimates can be calculated using available cancer risk models. Section 
81.21 also requires DOL to assume carcinoma in situ (ICD-9 
26 codes 230-234), neoplasms of uncertain behavior (ICD-9 
codes 235-238), and neoplasms of unspecified nature (ICD-9 code 239) 
are malignant, for purposes of estimating probability of causation.
---------------------------------------------------------------------------

    \26\ ICD-9 is a version of the standard system of classifying 
diseases that will be used by IREP. The most recent version of this 
system, ICD-10, will not be used because the cancer risk models have 
been constructed using ICD-9.
    See: The International Classification of Diseases Clinical 
Modification (9th Revision) Volume I&II. [1991] Department of Health 
and Human Services Publication No. (PHS) 91-1260, U.S. Government 
Printing Office, Washington, D.C.
---------------------------------------------------------------------------

    Sections 81.22-81.25 provide general guidelines for the use of 
NIOSH-IREP and specific applications to accommodate special 
circumstances anticipated. The special circumstances include claims in 
which: (1) The primary site of a metastasized cancer is unknown; (2) 
the subtype of leukemia presented lacks a single, optimal risk model in 
NIOSH-IREP; and (3) two or more primary cancers are presented, 
requiring further statistical adjustment of probability of causation 
estimates calculated using NIOSH-IREP.
    The procedure concerning subtypes of leukemia (2) is needed because 
of a limitation of the data on Japanese atomic bomb survivors, as 
discussed above and in the notice of proposed rulemaking. The general 
leukemia model in IREP allows for adjustment for age at exposure, which 
is an important modifier of leukemia risk. The data are too sparse, 
however, to allow for such an adjustment with respect to specific types 
of leukemia, with the exception of chronic myeloid leukemia. Since it 
is not possible to determine which factor, age at exposure or leukemia 
subtype, is more important to determining probability of causation for 
most specific types of leukemia, the guidelines require use of both the 
general model and the specific model. The guidelines require DOL to use 
the findings of whichever model produces the higher probability of 
causation estimate.
    Section 81.30 specifies one cancer to be considered non-radiogenic 
for the purposes of this rule: chronic lymphocytic leukemia (ICD-9 
Code: 204.1). DOL would assign a value of zero to the probability of 
causation for a claim based on this type of leukemia. There is general 
consensus among the scientific and medical communities that treatment 
of this leukemia as non-radiogenic is appropriate, and such treatment 
is consistent with other radiation illness compensation programs.

V. Significant Regulatory Action (Executive Order 12866)

    This rule is a ``significant regulatory action,'' within the 
meaning of Executive Order 12866, because it raises novel or legal 
policy issues arising out of the legal mandate established under 
EEOICPA. The rule is designed to establish objective guidelines, 
grounded in current science, to support DOL in the adjudication of 
applicable claims seeking compensation for cancer under EEOICPA. The 
guidelines will be applied by DOL to calculate a reasonable, 
scientifically supported determination of the probability that a cancer 
for which a claimant is seeking compensation was as likely as not 
caused by radiation doses incurred in the performance of duty by the 
covered employee. The financial cost to the federal government of 
applying these guidelines is covered under administrative expenses 
estimated by DOL under its rule (see FR 28948, May 25, 2001).
    The rule carefully explains the manner in which the regulatory 
action is consistent with the mandate for this action under 
Sec. 3623(c) of EEOICPA and implements the detailed requirements 
concerning this action under this section of EEOICPA. The rule does not 
interfere with State, local, and tribal governments in the exercise of 
their governmental functions.
    The rule is not considered economically significant, as defined in 
section 3(f)(1) of the Executive Order 12866. This rule has a 
subordinate role in the adjudication of claims under EEOICPA, serving 
as one element of an adjudication process administered by DOL under 20 
CFR Parts 1 and 30. DOL has determined that its rule fulfills the 
requirements of Executive Order 12866 and provides estimates of the 
aggregate cost of benefits and administrative expenses of implementing 
EEOICPA under its rule (see FR 28948, May 25, 2001).

VI. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA), 5 U.S.C. 601 et seq., 
requires each agency to consider the potential impact of its 
regulations on small entities including small businesses, small 
governmental units, and small not-for-profit organizations. HHS 
certifies that this rule will not have a significant economic impact on 
a substantial number of small entities within the meaning of the RFA. 
This rule affects only DOL, HHS, and some individuals filing 
compensation claims under EEOICPA. Therefore, a regulatory flexibility 
analysis as provided for under RFA is not required.

VII. Paperwork Reduction Act

    The Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et seq., requires 
an agency to invite public comment on and to obtain OMB approval of any 
regulation that requires ten or more people to report information to 
the agency or to keep certain records. This rule does not contain any 
information collection requirements. It provides guidelines only to the 
U.S. Department of Labor (DOL) for adjudicating compensation claims and 
thus requires no reporting or record keeping. Information required by 
DOL to apply these guidelines is being provided by HHS and by 
individual claimants to DOL under DOL regulations 20 CFR 30. Thus, HHS 
has determined that the PRA does not apply to this rule.

VIII. Small Business Regulatory Enforcement Fairness Act

    As required by Congress under the Small Business Regulatory 
Enforcement Fairness Act of 1996 (5 U.S.C. 801 et seq.), the Department 
will report to Congress promulgation of this rule. The report will 
state that the Department has concluded that this rule is not a ``major 
rule'' because it is not likely to result in

[[Page 22309]]

an annual effect on the economy of $100 million or more. However, this 
rule has a subordinate role in the adjudication of claims under 
EEOICPA, serving as one element of an adjudication process administered 
by DOL under 20 CFR Parts 1 and 30. DOL has determined that its rule is 
a ``major rule'' because it will likely result in an annual effect on 
the economy of $100 million or more.

IX. Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1531 
et seq.) directs agencies to assess the effects of Federal regulatory 
actions on State, local, and tribal governments, and the private 
sector, ``other than to the extent that such regulations incorporate 
requirements specifically set forth in law.'' For purposes of the 
Unfunded Mandates Reform Act, this rule does not include any Federal 
mandate that may result in increased annual expenditures in excess of 
$100 million by State, local or tribal governments in the aggregate, or 
by the private sector.

X. Executive Order 12988 (Civil Justice)

    This rule has been drafted and reviewed in accordance with 
Executive Order 12988, Civil Justice Reform and will not unduly burden 
the Federal court system. Probability of causation may be an element in 
reviews of DOL adverse decisions in the United States District Courts 
pursuant to the Administrative Procedure Act. However, DOL has 
attempted to minimize that burden by providing claimants an opportunity 
to seek administrative review of adverse decisions, including those 
involving probability of causation. HHS has provided a clear legal 
standard for DOL to apply regarding probability of causation. This rule 
has been reviewed carefully to eliminate drafting errors and 
ambiguities.

XI. Executive Order 13132 (Federalism)

    The Department has reviewed this rule in accordance with Executive 
Order 13132 regarding federalism, and has determined that it does not 
have ``federalism implications.'' The rule does not ``have substantial 
direct effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''

XII. Executive Order 13045 (Protection of Children From 
Environmental, Health Risks and Safety Risks)

    In accordance with Executive Order 13045, HHS has evaluated the 
environmental health and safety effects of this rule on children. HHS 
has determined that the rule would have no effect on children.

XIII. Executive Order 13211 (Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use)

    In accordance with Executive Order 13211, HHS has evaluated the 
effects of this rule on energy supply, distribution or use, and has 
determined that the rule will not have a significant adverse effect on 
them.

XIV. Effective Date

    The Secretary has determined, pursuant to 5 U.S.C. 553(d)(3), that 
there is good cause for this rule to be effective immediately to avoid 
undue hardship on and facilitate payment to eligible claimants.

List of Subjects in 42 CFR Part 81

    Cancer, Government Employees, Probability of Causation, Radiation 
Protection, Radioactive Materials, Workers' Compensation.

Text of the Rule

    For the reasons discussed in the preamble, the Department of Health 
and Human Services is amending 42 CFR to add Part 81 to read as 
follows:

PART 81--GUIDELINES FOR DETERMINING PROBABILITY OF CAUSATION UNDER 
THE ENERGY EMPLOYEES OCCUPATIONAL ILLNESS COMPENSATION PROGRAM ACT 
OF 2000

Subpart A--Introduction
Sec.
81.0   Background.
81.1   Purpose and Authority.
81.2   Provisions of EEOICPA concerning this part.
Subpart B--Definitions
81.4   Definition of terms used in this part.
Subpart C--Data Required To Estimate Probability of Causation
81.5   Use of personal and medical information
81.6   Use of radiation dose information.
Subpart D--Requirements for Risk Models Used To Estimate Probability of 
Causation
81.10   Use of cancer risk assessment models in NIOSH-IREP.
81.11   Use of uncertainty analysis in NIOSH-IREP.
81.12  Procedure for updating NIOSH-IREP.
Subpart E--Guidelines To Estimate Probability of Causation
81.20   Required use of NIOSH-IREP.
81.21   Cancers requiring the use of NIOSH-IREP.
81.22   General guidelines for use of NIOSH-IREP.
81.23   Guidelines for cancers for which primary site is unknown.
81.24   Guidelines for leukemia.
81.25   Guidelines for claims involving two or more primary cancers.
81.30   Non-radiogenic cancers.

Appendix A to Part 81--Glossary of ICD-9 codes and their cancer 
descriptions.

    Authority: 42 U.S.C. 7384n(c); E.O. 13179, 65 FR 77487, 3 CFR, 
2000 Comp., p. 321.

Subpart A--Introduction


Sec. 81.0  Background.

    The Energy Employees Occupational Illness Compensation Program Act 
(EEOICPA), 42 U.S.C. 7384-7385 [1994, supp. 2001], provides for the 
payment of compensation benefits to covered employees and, where 
applicable, survivors of such employees, of the United States 
Department of Energy, its predecessor agencies and certain of its 
contractors and subcontractors. Among the types of illnesses for which 
compensation may be provided are cancers. There are two categories of 
covered employees with cancer under EEOICPA for whom compensation may 
be provided. The regulations that follow under this part apply only to 
the category of employees described under paragraph (a) of this 
section.
    (a) One category is employees with cancer for whom probability of 
causation must be estimated or determined, as required under 20 CFR 
30.115.
    (b) The second category is members of the Special Exposure Cohort 
seeking compensation for a specified cancer, as defined under EEOICPA. 
The U.S. Department of Labor (DOL) which has primary authority for 
implementing EEOICPA, has promulgated regulations at 20 CFR 30.210 et 
seq. that identify current members of the Special Exposure Cohort and 
requirements for compensation. Pursuant to section 7384(q) of EEOICPA, 
the Secretary of HHS is authorized to add additional classes of 
employees to the Special Exposure Cohort.


Sec. 81.1  Purpose and Authority.

    (a) The purpose of this regulation is to establish guidelines DOL 
will apply to adjudicate cancer claims for covered employees seeking 
compensation for cancer, other than as members of the Special Exposure 
Cohort seeking compensation for a specified cancer. To award a claim, 
DOL must first determine that it is at least as likely as not that the 
cancer of the employee was caused by radiation doses incurred by the 
employee in the performance of

[[Page 22310]]

duty. These guidelines provide the procedures DOL must apply and 
identify the information DOL will use.
    (b) Section 7384(n)(b) of EEOICPA requires the President to 
promulgate these guidelines. Executive Order 13179 assigned 
responsibility for promulgating these guidelines to the Secretary of 
HHS.


Sec. 81.2  Provisions of EEOICPA concerning this part.

    EEOICPA imposes several general requirements concerning the 
development of these guidelines. It requires that the guidelines 
produce a determination as to whether it is at least as likely as not 
(a 50% or greater probability) that the cancer of the covered employee 
was related to radiation doses incurred by the employee in the 
performance of duty. It requires the guidelines be based on the 
radiation dose received by the employee, incorporating the methods of 
dose reconstruction to be established by HHS. It requires 
determinations be based on the upper 99 percent confidence interval 
(credibility limit) of the probability of causation in the 
RadioEpidemiological tables published under section 7(b) of the Orphan 
Drug Act (42 U.S.C. 241 note), as such tables may be updated. EEOICPA 
also requires HHS consider the type of cancer, past health-related 
activities, the risk of developing a radiation-related cancer from 
workplace exposure, and other relevant factors. Finally, it is 
important to note EEOICPA does not include a requirement limiting the 
types of cancers to be considered radiogenic for these guidelines.

Subpart B--Definitions


Sec. 81.4  Definition of terms used in this part.

    (a) Covered employee, for purposes of this part, means an 
individual who is or was an employee of DOE, a DOE contractor or 
subcontractor, or an atomic weapons employer, and for whom DOL has 
requested HHS to perform a dose reconstruction.
    (b) Dose and dose rate effectiveness factor (DDREF) means a factor 
applied to a risk model to modify the dose-risk relationship estimated 
by the model to account for the level of the dose and the rate at which 
the dose is incurred. As used in IREP, a DDREF value of greater than 
one implies that chronic or low doses are less carcinogenic per unit of 
dose than acute or higher doses.
    (c) Dose-response relationship means a mathematical expression of 
the way that the risk of a biological effect (for example, cancer) 
changes with increased exposure to a potential health hazard (for 
example, ionizing radiation).
    (d) EEOICPA means the Energy Employees Occupational Illness 
Compensation Program Act of 2000, 42 U.S.C. Secs. 7384-7385 [1994, 
supp. 2001].
    (e) Equivalent dose means the absorbed dose in a tissue or organ 
multiplied by a radiation weighting factor to account for differences 
in the effectiveness of the radiation in inducing cancer.
    (f) External dose means the portion of the equivalent dose that is 
received from radiation sources outside of the body.
    (g) Interactive RadioEpidemiological Program (IREP) means a 
computer software program that uses information on the dose-response 
relationship, and specific factors such as a claimant's radiation 
exposure, gender, age at diagnosis, and age at exposure to calculate 
the probability of causation for a given pattern and level of radiation 
exposure.
    (h) Internal dose means the portion of the equivalent dose that is 
received from radioactive materials taken into the body.
    (i) Inverse dose rate effect means a phenomenon in which the 
protraction of an exposure to a potential health hazard leads to 
greater biological effect per unit of dose than the delivery of the 
same total amount in a single dose. An inverse dose rate effect implies 
that the dose and dose rate effectiveness factor (DDREF) is less than 
one for chronic or low doses.
    (j) Linear energy transfer (LET) means the average amount of energy 
transferred to surrounding body tissues per unit of distance the 
radiation travels through body tissues (track length). Low LET 
radiation is typified by gamma and x rays, which have high penetrating 
capabilities through various tissues, but transfer a relatively small 
amount of energy to surrounding tissue per unit of track length. High 
LET radiation includes alpha particles and neutrons, which have weaker 
penetrating capability but transfer a larger amount of energy per unit 
of track length.
    (k) NIOSH means the National Institute for Occupational Safety and 
Health, Centers for Disease Control and Prevention, United States 
Department of Health and Human Services.
    (l) Non-radiogenic cancer means a type of cancer that HHS has found 
not to be caused by radiation, for the purposes of this regulation.
    (m) Primary cancer means a cancer defined by the original body site 
at which the cancer was incurred, prior to any spread (metastasis) to 
other sites in the body.
    (n) Probability of causation means the probability or likelihood 
that a cancer was caused by radiation exposure incurred by a covered 
employee in the performance of duty. In statistical terms, it is the 
cancer risk attributable to radiation exposure divided by the sum of 
the baseline cancer risk (the risk to the general population) plus the 
cancer risk attributable to the radiation exposure.
    (o) RadioEpidemiological Tables means tables that allow computation 
of the probability of causation for various cancers associated with a 
defined exposure to radiation, after accounting for factors such as age 
at exposure, age at diagnosis, and time since exposure.
    (p) Relative biological effectiveness (RBE) means a factor applied 
to a risk model to account for differences between the amount of cancer 
effect produced by different forms of radiation. For purposes of 
EEOICPA, the RBE is considered equivalent to the radiation weighting 
factor.
    (q) Risk model means a mathematical model used under EEOICPA to 
estimate a specific probability of causation using information on 
radiation dose, cancer type, and personal data (e.g., gender, smoking 
history).
    (r) Secondary site means a body site to which a primary cancer has 
spread (metastasized).
    (s) Specified cancer is a term defined in Sec. 7384(l)(17) of 
EEOICPA and 20 CFR 30.5(dd) that specifies types of cancer that, 
pursuant to 20 CFR part 30, may qualify a member of the Special 
Exposure Cohort for compensation. It includes leukemia (other than 
chronic lymphocytic leukemia), multiple myeloma, non-Hodgkin's 
lymphoma, renal cancers, and cancers of the lung (other than carcinoma 
in situ diagnosed at autopsy), thyroid, male breast, female breast, 
esophagus, stomach, pharynx, small intestine, pancreas, bile ducts, 
gall bladder, salivary gland, urinary bladder, brain, colon, ovary, 
liver (not associated with cirrhosis or hepatitis B), and bone.
    (t) Uncertainty is a term used in this rule to describe the lack of 
precision of a given estimate, the extent of which depends upon the 
amount and quality of the evidence or data available.
    (u) Uncertainty distribution is a statistical term meaning a range 
of discrete or continuous values arrayed around a central estimate, 
where each value is assigned a probability of being correct.
    (v) Upper 99 percent confidence interval is a term used in EEOICPA 
to mean credibility limit, the probability of causation estimate 
determined at the 99th percentile of the range of

[[Page 22311]]

uncertainty around the central estimate of probability of causation.

Subpart C--Data Required To Estimate Probability of Causation


Sec. 81.5  Use of personal and medical information.

    Determining probability of causation may require the use of the 
following personal and medical information provided to DOL by claimants 
under DOL regulations 20 CFR part 30:
    (a) Year of birth
    (b) Cancer diagnosis (by ICD-9 code) for primary and secondary 
cancers
    (c) Date of cancer diagnosis
    (d) Gender
    (e) Race/ethnicity (if the claim is for skin cancer or a secondary 
cancer for which skin cancer is a likely primary cancer)
    (f) Smoking history (if the claim is for lung cancer or a secondary 
cancer for which lung cancer is a likely primary cancer)


Sec. 81.6  Use of radiation dose information.

    Determining probability of causation will require the use of 
radiation dose information provided to DOL by the National Institute 
for Occupational Safety and Health (NIOSH) under HHS regulations 42 CFR 
part 82. This information will include annual dose estimates for each 
year in which a dose was incurred, together with uncertainty 
distributions associated with each dose estimate. Dose estimates will 
be distinguished by type of radiation (low linear energy transfer 
(LET), protons, neutrons, alpha, low-energy x-ray) and by dose rate 
(acute or chronic) for external and internal radiation dose.

Subpart D--Requirements for Risk Models Used To Estimate 
Probability of Causation


Sec. 81.10  Use of cancer risk assessment models in NIOSH IREP.

    (a) The risk models used to estimate probability of causation for 
covered employees under EEOICPA will be based on risk models updated 
from the 1985 NIH Radioepidemiological Tables. These 1985 tables were 
developed from analyses of cancer mortality risk among the Japanese 
atomic bomb survivor cohort. The National Cancer Institute (NCI) and 
Centers for Disease Control and Prevention (CDC) are updating the 
tables, replacing them with a sophisticated analytic software program. 
This program, the Interactive RadioEpidemiological Program (IREP)\1\, 
models the dose-response relationship between ionizing radiation and 33 
cancers using morbidity data from the same Japanese atomic bomb 
survivor cohort. In the case of thyroid cancer, radiation risk models 
are based on a pooled analysis of several international cohorts\1a\.
---------------------------------------------------------------------------

    \1\ NIOSH-IREP is available for public review on the NIOSH 
homepage at: www.cdc.gov/niosh/ocas/ocasirep/html.
    \1a\ Ron E, Lubin JH, Shore RE, et al. ``Thyroid cancer after 
exposure to external radiation: a pooled analysis of seven 
studies.'' Radiat. Res. 141:259-277, 1995.
---------------------------------------------------------------------------

    (b) NIOSH will change the risk models in IREP, as needed, to 
reflect the radiation exposure and disease experiences of employees 
covered under EEOICPA, which differ from the experiences of the 
Japanese atomic bomb survivor cohort. Changes will be incorporated in a 
version of IREP named NIOSH-IREP, specifically designed for 
adjudication of claims under EEOICPA. Possible changes in IREP risk 
models include the following:
    (1) Addition of risk models to IREP, as needed, for claims under 
EEOICPA (e.g., malignant melanoma and other skin cancers)
    (2) Modification of IREP risk models to incorporate radiation 
exposures unique to employees covered by EEOICPA (e.g., radon and low 
energy x rays from employer-required medical screening programs, 
adjustment of relative biological effectiveness distributions based on 
neutron energy).
    (3) Modification of IREP risk models to incorporate new 
understanding of radiation-related cancer effects relevant to employees 
covered by EEOICPA (e.g., incorporation of inverse dose-rate 
relationship between high LET radiation exposures and cancer; 
adjustment of the low-dose effect reduction factor for acute 
exposures).
    (4) Modification of IREP risk models to incorporate new 
understanding of the potential interaction between cancer risk 
associated with occupational exposures to chemical carcinogens and 
radiation-related cancer effects.
    (5) Modification of IREP risk models to incorporate temporal, race 
and ethnicity-related differences in the frequency of certain cancers 
occurring generally among the U.S. population.
    (6) Modifications of IREP to facilitate improved evaluation of the 
uncertainty distribution for the probability of causation for claims 
based on two or more primary cancers.


Sec. 81.11  Use of uncertainty analysis in NIOSH-IREP.

    (a) EEOICPA requires use of the uncertainty associated with the 
probability of causation calculation, specifically requiring the use of 
the upper 99% confidence interval (credibility limit) estimate of the 
probability of causation estimate. As described in the NCI 
document,2 uncertainty from several sources is incorporated 
into the probability of causation calculation performed by NIOSH-IREP. 
These sources include uncertainties in estimating: radiation dose 
incurred by the covered employee; the radiation dose-cancer 
relationship (statistical uncertainty in the specific cancer risk 
model); the extrapolation of risk (risk transfer) from the Japanese to 
the U.S. population; differences in the amount of cancer effect caused 
by different radiation types (relative biological effectiveness or 
RBE); the relationship between the rate at which a radiation dose is 
incurred and the level of cancer risk produced (dose and dose rate 
effectiveness factor or DDREF); and, the role of non-radiation risk 
factors (such as smoking history).
---------------------------------------------------------------------------

    \2\ Draft Report of the NCI-CDC Working Group to Revise the 1985 
NIH Radioepidemiological Tables, May 31, 2000, p. 17-18, p. 22-23.
---------------------------------------------------------------------------

    (b) NIOSH-IREP will operate according to the same general protocol 
as IREP for the analysis of uncertainty. It will address the same 
possible sources of uncertainty affecting probability of causation 
estimates, and in most cases will apply the same assumptions 
incorporated in IREP risk models. Different procedures and assumptions 
will be incorporated into NIOSH-IREP as needed, according to the 
criteria outlined under Sec. 81.10.


Sec. 81.12  Procedure to update NIOSH-IREP.

    (a) NIOSH may periodically revise NIOSH-IREP to add, modify, or 
replace cancer risk models, improve the modeling of uncertainty, and 
improve the functionality and user-interface of NIOSH-IREP.
    (b) Revisions to NIOSH-IREP may be recommended by the following 
sources:
    (1) NIOSH,
    (2) The Advisory Board on Radiation and Worker Health,
    (3) Independent reviews of NIOSH-IREP or elements thereof by 
scientific organizations (e.g., National Academy of Sciences),
    (4) DOL,
    (5) Public comment.
    (c) NIOSH will submit substantive changes to NIOSH-IREP (changes 
that would substantially affect estimates of probability of causation 
calculated using NIOSH-IREP, including the addition of new cancer risk 
models) to the Advisory Board on Radiation and Worker Health for 
review. NIOSH will obtain such review and address any recommendations 
of the review before completing and implementing the change.

[[Page 22312]]

    (d) NIOSH will inform the public of proposed changes provided to 
the Advisory Board for review. HHS will provide instructions for 
obtaining relevant materials and providing public comment in the notice 
announcing the Advisory Board meeting, published in the Federal 
Register.
    (e) NIOSH will publish periodically a notice in the Federal 
Register informing the public of proposed substantive changes to NIOSH-
IREP currently under development, the status of the proposed changes, 
and the expected completion dates.
    (f) NIOSH will notify DOL and publish a notice in the Federal 
Register notifying the public of the completion and implementation of 
substantive changes to NIOSH-IREP. In the notice, NIOSH will explain 
the effect of the change on estimates of probability of causation and 
will summarize and address relevant comments received by NIOSH.
    (g) NIOSH may take into account other factors and employ other 
procedures than those specified in this section, if circumstances arise 
that require NIOSH to implement a change more immediately than the 
procedures in this section allow.

Subpart E--Guidelines To Estimate Probability of Causation


Sec. 81.20  Required use of NIOSH-IREP.

    (a) NIOSH-IREP is an interactive software program for estimating 
probability of causation for covered employees seeking compensation for 
cancer under EEOICPA, other than as members of the Special Exposure 
Cohort seeking compensation for a specified cancer.
    (b) DOL is required to use NIOSH-IREP to estimate probability of 
causation for all cancers, as identified under Secs. 81.21 and 81.23.


Sec. 81.21  Cancers requiring the use of NIOSH-IREP.

    (a) DOL will calculate probability of causation for all cancers, 
except chronic lymphocytic leukemia as provided under Sec. 81.30, using 
NIOSH-IREP.
    (b) Carcinoma in situ (ICD-9 codes 230-234), neoplasms of uncertain 
behavior (ICD-9 codes 235-238), and neoplasms of unspecified nature 
(ICD-9 code 239) are assumed to be malignant, for purposes of 
estimating probability of causation.
    (c) All secondary and unspecified cancers of the lymph node (ICD-9 
code 196) shall be considered secondary cancers (cancers resulting from 
metastasis of cancer from a primary site). For claims identifying 
cancers of the lymph node, Table 1 in Sec. 81.23 provides guidance for 
assigning a primary site and calculating probability of causation using 
NIOSH-IREP.


Sec. 81.22  General guidelines for use of NIOSH-IREP.

    DOL will use procedures specified in the NIOSH-IREP Operating Guide 
to calculate probability of causation estimates under EEOICPA. The 
guide provides current, step-by-step instructions for the operation of 
IREP. The procedures include entering personal, diagnostic, and 
exposure data; setting/confirming appropriate values for variables used 
in calculations; conducting the calculation; and, obtaining, 
evaluating, and reporting results.


Sec. 81.23  Guidelines for cancers for which primary site is unknown.

    (a) In claims for which the primary cancer site cannot be 
determined, but a site of metastasis is known, DOL will calculate 
probability of causation estimates for various likely primary sites. 
Table 1, below, indicates the primary cancer site(s) DOL will use in 
NIOSH-IREP when the primary cancer site is unknown.

Table 1

    Primary cancers (ICD-9 codes 3) for which probability of 
causation is to be calculated, if only a secondary cancer site is 
known. ``M'' indicates cancer site should be used for males only, and 
``F'' indicates the cancer site should be used for females only. A 
glossary of cancer descriptions for each ICD-9 code is provided in 
Appendix A to this part.
---------------------------------------------------------------------------

    \3\ The International Classification of Diseases Clinical 
Modification (9th Revision) Volume I&II. [1991] Department of Health 
and Human Services Publication No. (PHS) 91-1260, U.S. Government 
Printing Office, Washington D.C.

------------------------------------------------------------------------
Secondary cancer (ICD-9 code)     ICD-9 code of likely primary cancers
------------------------------------------------------------------------
Lymph nodes of head, face and  141, 142 (M), 146 (M), 149 (F), 161 (M),
 neck (196.0).                  162, 172, 173, 174 (F), 193 (F).
Intrathoracic lymph nodes      150 (M), 162, 174 (F).
 (196.1).
Intra-abdominal lymph nodes    150 (M), 151 (M), 153, 157 (F), 162, 174
 (196.2).                       (F), 180 (F), 185 (M), 189, 202 (F).
Lymph nodes of axilla and      162, 172, 174 (F).
 upper limb (196.3).
Inguinal and lower limb lymph  154 (M), 162, 172, 173 (F), 187 (M).
 nodes (196.5).
Intrapelvic lymph nodes        153 (M), 154 (F), 162 (M), 180 (F), 182
 (196.6).                       (F), 185 (M), 188.
Lymph nodes of multiple sites  150 (M), 151 (M), 153 (M), 162, 174 (F).
 (196.8).
Lymph nodes, site unspecified  150 (M), 151, 153, 162, 172, 174 (F), 185
 (196.9).                       (M).
Lung (197.0).................  153, 162, 172 (M), 174 (F), 185 (M), 188
                                (M), 189.
Mediastinum (197.1)..........  150 (M), 162, 174 (F).
Pleura (197.2)...............  150 (M), 153 (M), 162, 174 (F), 183 (F),
                                185 (M), 189 (M).
Other respiratory organs       150, 153 (M), 161, 162, 173 (M), 174 (F),
 (197.3).                       185 (M), 193 (F).
Small intestine, including     152, 153, 157, 162, 171, 172 (M), 174
 duodenum (197.4).              (F), 183 (F), 189 (M).
Large intestine and rectum     153, 154, 162, 174 (F), 183 (F), 185 (M).
 (197.5).
Retroperitoneum and            151, 153, 154 (M), 157, 162 (M), 171, 174
 peritoneum (197.6).            (F), 182 (F), 183 (F).
Liver, specified as secondary  151 (M), 153, 154 (M), 157, 162, 174 (F).
 (197.7).
Other digestive organs         150 (M), 151, 153, 157, 162, 174 (F), 185
 (197.8).                       (M).
Kidney (198.0)...............  153, 162, 174 (F), 180 (F), 185 (M), 188,
                                189, 202 (F).
Other urinary organs (198.1).  153, 174 (F), 180 (F), 183 (F), 185 (M),
                                188, 189 (F).
Skin (198.2).................  153, 162, 171 (M), 172, 173 (M), 174 (F),
                                189 (M).
Brain and spinal cord (198.3)  162, 172 (M), 174 (F).
Other parts of nervous system  162, 172 (M), 174 (F), 185 (M), 202.
 (198.4).
Bone and bone marrow (198.5).  162, 174 (F), 185 (M).
Ovary (198.6)................  153 (F), 174 (F), 183 (F).
Suprarenal gland (198.7).....  153 (F), 162, 174 (F).
Other specified sites (198.8)  153, 162, 172 (M), 174 (F), 183 (F), 185
                                (M), 188 (M).
------------------------------------------------------------------------


[[Page 22313]]

    (b) DOL will select the site producing the highest estimate for 
probability of causation to adjudicate the claim.


Sec. 81.24  Guidelines for leukemia.

    (a) For claims involving leukemia, DOL will calculate one or more 
probability of causation estimates from up to three of the four 
alternate leukemia risk models included in NIOSH-IREP, as specified in 
the NIOSH-IREP Operating Guide. These include: ``Leukemia, all types 
except CLL'' (IDC-9 codes: 204-208, except 204.1), ``acute lymphocytic 
leukemia'' (ICD-9 code: 204.0), and ``acute myelogenous leukemia'' 
(ICD-9 code: 205.0).
    (b) For leukemia claims in which DOL calculates multiple 
probability of causation estimates, as specified in the NIOSH-IREP 
Operating Guide, the probability of causation estimate DOL assigns to 
the claim will be based on the leukemia risk model producing the 
highest estimate for probability of causation.


Sec. 81.25  Guidelines for claims including two or more primary 
cancers.

    For claims including two or more primary cancers, DOL will use 
NIOSH-IREP to calculate the estimated probability of causation for each 
cancer individually. Then DOL will perform the following calculation 
using the probability of causation estimates produced by NIOSH-IREP:

EQUATION 1

Calculate: 1-[{1 x PC1}  x  {1-PC2}  x  . . .  x 


{1-PCn}] = PCtotal, 
where PC1 is the probability of causation for one of the 
primary cancers identified in the claim, PC2 is the 
probability of causation for a second primary cancer identified in the 
claim, and PCn is the probability of causation for the nth 
primary cancer identified in the claim. PCtotal is the 
probability that at least one of the primary cancers (cancers 1 through 
``n'') was caused by the radiation dose estimated for the claim when 
Equation 1 is evaluated based on the joint distribution of 
PC1, . . ., PCn.\4\ DOL will use the probability 
of causation value calculated for PCtotal to adjudicate the 
claim.


Sec. 81.30  Non-radiogenic cancers

    The following cancers are considered non-radiogenic for the 
purposes of EEOICPA and this part. DOL will assign a probability of 
causation of zero to the following cancers:
    (a) Chronic lymphocytic leukemia (ICD-9 code: 204.1)
    (b) [Reserved]

------------
    \4\ Evaluating Equation 1 based on the individual upper 99th 
percentiles of PC1, . . ., PCn approximates 
the upper 99th percentile of PCtotal whenever 
PC1, . . ., PCn are highly related, e.g., when 
a common dose-reconstruction is the only non-negligible source of 
uncertainty in the individual PCi's. However, this 
approximation can overestimate it if other sources of uncertainty 
contribute independently to the PC1, . . ., 
PCn, whereas treating the joint distribution as fully 
independent could substantially underestimate the upper 99th 
percentile of PCtotal whenever the individual 
PCi's are positively correlated.

     Appendix A to Part 81--Glossary of ICD-9 Codes and Their Cancer
                            Descriptions \1\
------------------------------------------------------------------------
                ICD-9 code                       Cancer description
------------------------------------------------------------------------
140.......................................  Malignant neoplasm of lip.
141.......................................  Malignant neoplasm of
                                             tongue.
142.......................................  Malignant neoplasm of major
                                             salivary glands.
143.......................................  Malignant neoplasm of gum.
144.......................................  Malignant neoplasm of floor
                                             of mouth.
145.......................................  Malignant neoplasm of other
                                             and unspecified parts of
                                             mouth.
146.......................................  Malignant neoplasm of
                                             oropharynx.
147.......................................  Malignant neoplasm of
                                             nasopharynx.
148.......................................  Malignant neoplasm of
                                             hypopharynx.
149.......................................  Malignant neoplasm of other
                                             and ill-defined sites
                                             within the lip, oral
                                             cavity, and pharynx.
150.......................................  Malignant neoplasm of
                                             esophagus.
151.......................................  Malignant neoplasm of
                                             stomach.
152.......................................  Malignant neoplasm of small
                                             intestine, including
                                             duodenum.
153.......................................  Malignant neoplasm of colon.
154.......................................  Malignant neoplasm of
                                             rectum, rectosigmoid
                                             junction, and anus.
155.......................................  Malignant neoplasm of liver
                                             and intrahepatic bile
                                             ducts.
156.......................................  Malignant neoplasm of gall
                                             bladder and extrahepatic
                                             bile ducts.
157.......................................  Malignant neoplasm of
                                             pancreas.
158.......................................  Malignant neoplasm of
                                             retroperitoneum and
                                             peritoneum.
159.......................................  Malignant neoplasm of other
                                             and ill-defined sites
                                             within the digestive organs
                                             and peritoneum.
160.......................................  Malignant neoplasm of nasal
                                             cavities, middle ear, and
                                             accessory sinuses.
161.......................................  Malignant neoplasm of
                                             larynx.
162.......................................  Malignant neoplasm of
                                             trachea, bronchus and lung.
163.......................................  Malignant neoplasm of
                                             pleura.
164.......................................  Malignant neoplasm of
                                             thymus, heart, and
                                             mediastinum.
165.......................................  Malignant neoplasm of other
                                             and ill-defined sites
                                             within the respiratory
                                             system and intrathoracic
                                             organs.
170.......................................  Malignant neoplasm of bone
                                             and articular cartilage.
171.......................................  Malignant neoplasm of
                                             connective and other soft
                                             tissue.
172.......................................  Malignant melanoma of skin.
173.......................................  Other malignant neoplasms of
                                             skin.
174.......................................  Malignant neoplasm of female
                                             breast.
175.......................................  Malignant neoplasm of male
                                             breast.
179.......................................  Malignant neoplasm of
                                             uterus, part unspecified.
180.......................................  Malignant neoplasm of cervix
                                             uteri.
181.......................................  Malignant neoplasm of
                                             placenta.
182.......................................  Malignant neoplasm of body
                                             of uterus.
183.......................................  Malignant neoplasm of ovary
                                             and other uterine adnexa.
184.......................................  Malignant neoplasm of other
                                             and unspecified female
                                             genital organs.
185.......................................  Malignant neoplasm of
                                             prostate.
186.......................................  Malignant neoplasm of
                                             testis.

[[Page 22314]]

 
187.......................................  Malignant neoplasm of penis
                                             and other male genital
                                             organs.
188.......................................  Malignant neoplasm of
                                             urinary bladder.
189.......................................  Malignant neoplasm of kidney
                                             and other unspecified
                                             urinary organs.
190.......................................  Malignant neoplasm of eye.
191.......................................  Malignant neoplasm of brain.
192.......................................  Malignant neoplasm of other
                                             and unspecified parts of
                                             nervous system.
193.......................................  Malignant neoplasm of
                                             thyroid gland.
194.......................................  Malignant neoplasm of other
                                             endocrine glands and
                                             related structures.
195.......................................  Malignant neoplasm of other
                                             and ill-defined sites.
196.......................................  Secondary and unspecified
                                             malignant neoplasm of the
                                             lymph nodes.
197.......................................  Secondary malignant neoplasm
                                             of the respiratory and
                                             digestive organs.
198.......................................  Secondary malignant neoplasm
                                             of other tissue and organs.
199.......................................  Malignant neoplasm without
                                             specification of site.
200.......................................  Lymphosarcoma and
                                             reticulosarcoma.
201.......................................  Hodgkin's disease.
202.......................................  Other malignant neoplasms of
                                             lymphoid and histiocytic
                                             tissue.
203.......................................  Multiple myeloma and other
                                             immunoproliferative
                                             neoplasms.
204.......................................  Lymphoid leukemia
205.......................................  Myeloid leukemia.
206.......................................  Monocytic leukemia.
207.......................................  Other specified leukemia.
208.......................................  Leukemia of unspecified cell
                                             type.
------------------------------------------------------------------------
1 The International Classification of Diseases Clinical Modification
  (9th Revision) Volume I&II. [1991] Department of Health and Human
  Services Publication No. (PHS) 91-1260, U.S. Government Printing
  Office, Washington, D.C.


    Dated: April 10, 2002.
Tommy G. Thompson,
Secretary, Department of Health and Human Services.
[FR Doc. 02-10764 Filed 4-30-02; 8:45 am]
BILLING CODE 4160-17-P