Background on work-related gradual process, disease, or infection injuries

This section describes the background on WRGPDI injuries and why they are covered under the AC Scheme.

A work-related gradual process, disease, or infection injury

A WRGPDI is caused by a work-related task or environment.

Examples of WRGPDI injuries include those arising from working with substances, such as asbestos, which cause illness over time. Other examples include performing tasks that involve a particular forceful and repeated movement that causes a gradual onset injury. Other WRGPDI injuries can be caused by a single exposure, such as certain infections from animals or their carcasses.

WRGPDI injury does not include work-related mental injury. This is covered under section 21B, a separate section of the AC Act unrelated to WRGPDI injury cover, in certain circumstances. Work-related mental injury will not be considered as part of this review.

Cover for work-related gradual process, disease, or infection injuries

Cover for WRGPDI injury has been a fundamental component of workers compensation schemes in Aotearoa New Zealand in the past and of workers compensation schemes internationally to date. It is a requirement under ILO Convention 42, to which Aotearoa New Zealand is a party, for members to provide compensation to workers incapacitated by occupational diseases.

The AC Scheme generally provides cover for injuries (for example, a broken leg), but not for illnesses. Illnesses are cared for through the health and welfare system when they are not a result of somebody’s work activities. However, the WRGPDI settings in the AC Act provide cover for gradual process, diseases and infection caused by work.

These provisions acknowledge that not all injuries have instant effects, some work activities are higher risk than others and workers may have restricted control over their work tasks or environments that cause a disease, injury, or illness.

There are 2 ways that WRGPDI injuries are covered in the AC Act. The first route involves using the three-step test (set out in section 30(2) of the AC Act). This test is used to determine if a personal injury is, on the balance of probabilities, more likely to be caused by a work-related factor than not.

The three-step test enables ACC to consider claims for a variety of WRGPDI injuries, including hearing loss and musculoskeletal conditions, which can also be caused by non-work factors (such as ageing). ACC has recently released a short video describing how WRGPDI injury cover works using the three-step test, which you can watch at the link below.

The essentials of work-related gradual process injury(external link) — YouTube

Occupational Diseases in Schedule 2

The second route to WRGPDI injury cover is being diagnosed with an occupational disease that is on Schedule 2. Schedule 2 provides a simpler pathway to AC cover for individuals who develop an occupational disease. It is appropriate to have a streamlined process when there is existing strong scientific evidence of a causal link between work and a disease, infection or gradual process, as this provides improved efficiency for claimants and decision-makers throughout the claim process.  

The inclusion of occupational diseases in Schedule 2 has reflected strong scientific evidence of a causal link to work to render any other cause unlikely. This is usually demonstrated through separate, good quality studies demonstrating a causal link. Diseases that are not included in Schedule 2 can still be considered for cover through the three-step test.

An occupational disease being listed on Schedule 2 does not guarantee the acceptance of a claim. Claims for cover under Schedule 2 can be declined under section 60 of the AC Act if a claimant does not have a personal injury (e.g., they make a claim for exposure only), or if a personal injury was not caused by their employment (e.g., the causal factor for the condition described in Schedule 2 was not present in their work activities).

The occupational diseases listed in Schedule 2 are largely based on the ILO List which was initially created in 1934 and most recently updated in 2010. The ILO, as part of its workers’ compensation commitments, recommended to members that they implement a list, test, or mixed approach to provide workers’ compensation for occupational diseases.

Aotearoa New Zealand’s approach uses both Schedule 2 and the three-step test to compensate workers for WRGPDI injuries. This mixed approach combines the certainty of cover from the Schedule 2 list of occupational diseases, with the three-step test providing the ability for a flexible response to injuries with less causative evidence linking them to work or new and emerging circumstances.

Last updated: 05 April 2023