Skip directly to site content Skip directly to search


Español  Other Languages


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
 Search
		×
			NIOSH
			NIOSH
				All CDC
				Submit
			For a full list of topics:A-Z Index
			Advanced Search
		Advanced Search


NIOSH Radiation Dose Reconstruction Program








alert icon
            Cybersecurity Modernization Initiative
                We are taking steps to continue to modernize and secure our data, applications, and systems. We completed the first phase and restored many of the functions put on pause in May 2021. Now that the first phase is complete, work will resume at a slower pace but will speed up as new systems and applications are brought online. For more information and updates, please visit our Cybersecurity Modernization Initiative web page.
								

				FAQs: Probability of Causation (POC)						Print
																Related Pages
										The Department of Labor (DOL) is responsible for determining the probability that a cancer included in a claim under EEOICPA (The Act) was caused by workers’ exposure to radiation during nuclear weapons production. DOL will determine the “probability of causation” for each claim for which NIOSH is required to complete a dose reconstruction. Generally, with some exceptions, these claims are for workers who are not a member of the Special Exposure Cohort.
To find answers to your questions about Probability of Causation, click any one of the questions listed below to view its answer.
Probability of CausationWhat is "probability of causation"?
	Under EEOICPA (The Act), probability of causation is a measure of how likely it is that an energy employee’s cancer was “at least as likely as not” caused by occupational exposure to ionizing radiation.What does dose reconstruction have to do with the probability of causation?
	The Department of Labor (DOL) will use the energy employee’s personal characteristics, employment, medical information, and dose reconstruction results developed by NIOSH to determine the probability of causation.What is the Probability of Causation rule?
	This rule provides the guidelines that DOL uses to determine the degree of likelihood that a cancer included in a case was “at least as likely as not” caused by the energy employee’s exposure to radiation during nuclear weapons production.Where can I find a copy of the Probability of Causation rule?
	A copy of the Probability of Causation rule can be found on our website on The Act page.How is probability of causation calculated under EEOICPA (The Act)?
	NIOSH developed a computer program that is used by DOL to determine the probability of causation. The computer program, known as NIOSH-IREP, uses cancer risk models developed primarily by the National Cancer Institute (NCI) to estimate the probability of causation under The Act.
The risk models take into account the energy employee’s cancer type, year of birth, year of cancer diagnosis, exposure information (years of exposure, radiation type, and dose). Smoking history is taken into account for lung cancer cases. Ethnicity is taken into account for skin cancer cases. Under Part B of the Act, exposures to other occupational, environmental, or dietary carcinogens are not currently taken into consideration for the probability of causation calculation.What is the significance of the probability of causation calculation?
	Probability of causation is expressed as a percentage between 0 and 100. A value of 100% means that it is certain that the radiation dose was the cause of the cancer. A value of 0% means that it is certain that the radiation dose was not the cause of the cancer. As defined in The Act, probability of causation values greater than or equal to 50% at the upper 99th percentile credibility limit mean that it is “at least as likely as not” that the radiation dose caused the energy employee’s cancer. Therefore, if the probability of causation for your case is less than 50%, you will not be entitled to compensation. If your probability of causation is between 50% or greater, DOL will recommend that you receive compensation.Does NIOSH determine/calculate the percent that determines the compensability of the claim?
	No, NIOSH reconstructs a worker’s radiation dose and determines a final estimate of the worker’s exposure to radiation. The results from a worker’s dose reconstruction are sent to DOL. DOL determines the probability of causation – the likelihood that the worker’s cancer was related to radiation exposure received while employed at a covered facility.What is uncertainty?
	A term used to describe the lack of precision and accuracy of a given estimate, the extent of which depends upon the amount and quality of the evidence or data available.What are some examples of uncertainty?
	Some statistical issues associated with epidemiological studies (e.g., possible measurement error, possible effects of confounding variables, etc) are:
Amount of radiation exposure
Dose-response assumptions
Transfer of “excess risk” from Japanese and other exposed populations to EEOICPA claimant populationWhat is the effect of uncertainty on the probability of causation?
	Uncertainty is built into nearly every part of the process of estimating causation
Uncertainty distributions are used in dose reconstruction, cancer risk models, etc.
“Credibility limits” are placed around the central estimate of PC
Upper 99th percentile determines final PC result and claim outcome
An accounting of uncertainty is necessary because the upper 99% credibility limit of PC is used in adjudicating claims for compensation
Uncertainty is often a major contributor to PCWhat is an uncertainty distribution?
	A range of discrete or continuous values arrayed to encompass, with high confidence, the true but unknown values of a given quantity or parameter.What is the Upper 99th percent credibility limit?
	The Upper 99th percent credibility limit is the 99th percentile of the range of values in an uncertainty distribution. The uncertainty distribution of the probability of causation (PC) is first estimated, and the upper 99th percentile of this distribution is compared to the decision criterion (a PC of 50%) to determine eligibility for compensation.What factors could influence the probability of causation result?
	Dose reconstruction efficiency process
Erring on the side of the claimant
During case development by DOL
Selection of IREP cancer model: policy often requires running 2 or more models and using the highest PC
Use of NIOSH-IREP “combined” lung cancer risk model
Handling of “unknown primary” cancers
Handling of claims with more than one primary cancer
Special “multiple primary” equation increases the likelihood of compensation.
NIOSH-IREP cancer risk models
Personal characteristics: gender, age at exposure, age at diagnosis, latency, smoking history, ethnicity
Reconstructed radiation dose: organ dose, radiation type, radiation energy, exposure rate
Uncertainty: in cancer risk models, in dose
Policy: multiple primary cancers, unknown primary cancer, alternate cancersHow does NIOSH calculate the probability of causation when a claim has more than one primary cancer?
	NIOSH-IREP includes a procedure to calculate an upper 99% credibility limit of PC when a claim for compensation involves more than one primary cancer.
In all these cases, NIOSH-IREP is run for each primary cancer separately, and the upper 99% credibility limit of probability of causation (PC) for all cancers combined is computed based on the upper 99% credibility limits of all the cancers involved, using the Multiple Cancer Equation:*PCtotal* = 1 – [(1 – *PC*1)x(1 – *PC*2)x...x(1 – *PCn*)]I reported new cancers to DOL and they sent my claim to NIOSH for a new dose reconstruction. I received the results from the new dose reconstruction. The probability of causation is even lower than the first dose reconstruction. Why did this happen?
	NIOSH understands this concern. It may seem obvious that when additional cancers are added to a dose reconstruction it would increase the probability that radiation caused the multiple cancers. However, in some cases, the NIOSH dose reconstruction will result in a lower probability of causation when additional cancers are added. An explanation for how and why this can happen is as follows:
Accurately estimating the exposure a worker received while working at a covered facility is a time consuming process. In order to complete dose reconstructions in as timely and efficient a manner as possible, NIOSH may make assumptions on dose estimates that are favorable to the claimant in order to simplify the dose reconstruction process.
For instance, instead of completing a dose reconstruction which precisely estimates the worker’s exposure for cases that would most likely result in a probability of causation well below the 50% necessary for the claim to be compensable by DOL, NIOSH will significantly over-estimate the exposure based on the highest levels of exposure observed or possible for the facility. If the claim will not be compensable even when using these significantly over-estimated exposure estimates, then no further refinement to the dose reconstruction is required.
This manner of dose reconstruction is called an “efficiency measure.” It allows NIOSH to issue a timely dose reconstruction where attempts to refine the exposure estimate would not result in a compensable claim (i.e., a full dose reconstruction would in all likelihood produce a much lower probability of causation than the over-estimated exposure values used).
Anytime a new cancer(s) is reported to NIOSH by DOL, NIOSH is required to rework the dose reconstruction to include the new cancer(s). If the new cancer(s) creates a potentially compensable case, NIOSH must refine the dose reconstruction using more probable and precise exposure estimates and not the significant over-estimates as mentioned above. These new, more accurate exposure estimates will be lower than the original estimate because we no longer use the assumptions which overestimated the radiation dose for the cancer found in the initial dose reconstruction. The revised radiation dose estimate may result in a probability of causation for the new cancer(s) that is lower than the non-compensable estimate that was obtained for the first cancer using the over-estimated radiation exposure. That is why the addition of a new cancer(s) may result in a probability of causation that is lower than the probability found for the single original cancer. However, this does not always occur when a new cancer(s) is added to a claim and NIOSH has to rework the dose reconstruction. It is possible for additional cancer(s) to produce a full dose reconstruction that will be determined to be compensable by DOL.
The use of “efficiency measures” and procedures for dose reconstructions that NIOSH follows under The Act are described in detail in Final Rule: Methods for Radiation Dose Reconstruction under EEOICPA–42 CFR 82 [ PDF 129 KB (23 pages)].Who do I contact if I have additional questions about probability of causation?
	If you have additional questions about probability of causation, please contact DCAS by email at dcas@cdc.gov or ocas@cdc.gov or 513-533-6800 (toll-free at 1-877-222-7570).
							
					
							Last Reviewed:  June 30, 2022						Source: 	National Institute for Occupational Safety and Health
					Facebook
        Twitter
        LinkedIn
        Syndicate homeRadiation Dose ReconstructionAbout DCASThe Act/EEOICPADose Reconstruction (DR)plus iconDataplus iconSourcesFormats & TypesSensitive DataWork History                            Phone CallData Search and Capture EffortsMethodsProductionTechnical Documents Used in Dose ReconstructionsProgram Evaluation Reports and PlansQuality Assurance and Quality ControlSupport ContractorSoftware (IMBA)RECA ClaimsProbability of Causationplus iconCalculating PCNews & UpdatesNIOSH-IREP SoftwareSpecial Exposure Cohortplus iconSubmit a PetitionCheck Petition Statusplus iconSEC Status TableGet HelpResidual ContaminationAdvisory Boardplus iconPublic MeetingsSubcommittee and Work GroupsSEC Petition RecommendationsTechnical Support for the Review of NIOSH Dose Reconstruction ProgramReports from the Advisory Board's Technical Support ContractorTechnical Review Summaries from the Technical Support ContractorProceduresCorrespondenceWork Site InformationPublications & ProductsProgram ReviewsReports to CongressPolicies, Procedures, and GuidelinesNIOSH Public DocketRelated Program LinksContact UsHELPplus iconHelp A – ZAccessibilityAcronymsFrequently Asked Questions (FAQs)plus iconThe ActCase ConcernsClaimant CorrespondenceConflict or BiasDose ReconstructionFreedom of Information Act (FOIA)National Defense Authorization ActNIOSH-IREPProbability of CausationResidual Contamination ReportResponsibilities under Subtitle B of EEOICPA (The Act)Special Exposure CohortTechnical DocumentsWork History Phone CallGlossary Follow NIOSH Facebook
Pinterest
Twitter
YouTube
 NIOSH Homepage NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs
Contact NIOSH


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue