Conditions for Entitlement – Occupational Diseases Policy 21-111 | Effective Date: March 18, 2026

Policy

An occupational disease is any disease that is peculiar to or characteristic of a particular industrial process, trade or occupation. Occupational diseases or related disablements may have occurred over time and may have resulted from an exposure with one employer or from multiple exposures at various workplaces.

WorkSafeNB makes decisions on acceptance of all claims, including occupational disease claims, using Section 7 of the Workers’ Compensation Act (WC Act) and Policy 21-100 Conditions for Entitlement – General Principles. However, given the complexity of occupational diseases, this policy provides additional information for decision-making on occupational diseases.

Specifically, guidance is provided to inform:

• Population-level causation: Whether the identified disease is recognized as an occupational disease in the general population; and
• Individual causation: The type of information gathered to determine whether it is more likely than not that the worker's disease is work-related.

To determine the existence of an occupational disease at the population level, WorkSafeNB relies on two approaches:

• Use of Appendix A, which outlines diseases that WorkSafeNB considers occupational diseases; or
• By evaluating scientific and medical literature to determine the link between the disease and the characteristics of a particular trade, occupation, or work environment.

Regardless of the approach, occupational diseases must undergo WorkSafeNB’s adjudication process to determine if the disease arose out of and in the course of employment.

To make a decision on the claim, WorkSafeNB gathers and analyzes all information related to the claim, as per Policy 21-113 Decision-making. WorkSafeNB considers medical evidence to be the most important information for establishing if a work-related exposure could have caused the disease. When the preponderance of all the evidence weighs more heavily towards that the disease is an occupational disease that arose out of and in the course of employment, the claim is accepted.

For more information on the types of medical and scientific literature WorkSafeNB accepts, see Policy 25-014 Medical Aid Decisions.

For the decision-making process for occupational hearing loss claims, please see Policy 21-112 Occupational Hearing Loss and for infectious diseases claims, please see Policy 21-109 Conditions for Entitlement – Infectious Diseases.

Interpretation

Determining an occupational disease at a population level

1. WorkSafeNB primarily consults Appendix A to confirm the diagnosed illness as an occupational disease. If the disease is not listed in the appendix, WorkSafeNB applies the Bradford Hill criteria to determine a potential causal link between exposure and disease. 

2. The Bradford Hill criteria is a tool that was developed to interpret epidemiological evidence of a general causal relationship between exposure to an agent and the disease.  WorkSafeNB applies the Bradford Hill criteria to its analysis of medical and scientific literature to determine any causal association between the exposure and the disease. Specifically, WorkSafeNB uses this criteria to determine: 

• Plausibility – Is there a biologically plausible mechanism linking exposure and disease? 
• Temporal – Did the exposure precede disease onset appropriately?
• Specificity – Is the disease associated specifically with the exposure type?
• Dose-response – Does severity increase with exposure dose or duration?
• Consistency – Are results consistent across multiple studies?
• Strength of association – the relative incidence of the condition under study between those exposed and those non-exposed.

3. Bradford Hill’s strength of association criteria is measured using the attributable risk fraction to determine whether it is more likely than not that the type of occupational exposure reported is capable of causing the disease in the general population. An Attributable Risk Fraction of:

• Fifty percent or greater means it is more probable than not that a case of the disease is attributable to the specified agent, exposure, or occupation;
• Between twenty-five and forty-nine percent means a case of the disease could possibly be attributable to the specified agent, exposure, or occupation; but it is not probable; or
• Less than twenty-five percent means there is insufficient evidence to suggest that a case of the disease is attributable to the specified agent, exposure or occupation.

Determining if the specific exposure caused the worker’s disease

4. Population-level information plays a key role in WorkSafeNB's decision-making process. However, even with strong evidence of causality at the population level, the worker’s specific exposure and individual circumstances must be considered.

5. In addition to the information at the population level, WorkSafeNB examines the specific facts and information of the worker to determine if it is reasonable that the individual disease arose out of and in the course of employment, including:

• Latency period specific to that disease;
• Pathology reports;
• Specialists’ reports;
• Where the exposure occurred;
• Type, nature, duration, and frequency of exposure;
• Specificity of exposure;
• Whether or not personal protective equipment was used;
• The worker’s medical history; and
• Evidence of alternate cause.

6. WorkSafeNB reviews all information on file to assess its reliability and relevance. Information deemed both reliable and relevant is admitted as evidence for the purpose of determining:

• The worker was exposed to the substance that was reported to have caused the disease;
• The exposure occurred at work; and
• The exposure caused the disease.

7. Occupational diseases commonly involve mixed causation. Occupational exposure need not be the sole or primary cause of a disease. Entitlement may be established where, on a preponderance of evidence, occupational exposure materially contributed to the development or clinical manifestation of the disease, consistent with Section 7 of the Workers’ Compensation Act.

Date of accident

8. For occupational disease, other than occupational hearing loss, the date of accident is the date of disablement. When there is no evidence of disablement, WorkSafeNB uses the date of diagnosis as the date of accident. For more information, please see Policy 21-106 Accident Reporting and Application for Benefits.

Previous versions

• Policy 21-111 Conditions for Entitlement – Occupational Diseases release 3, effective January 17, 2019
• Policy 21-111 Conditions for Entitlement – Occupational Diseases release 2, effective February 20, 2013
• Policy 21-111 Conditions for Entitlement – Occupational Diseases, release 1, effective February 28, 2008