Deanna Trevarthen died from mesothelioma in December 2016 at the age of 45. She believed her illness arose from contact as a child with her father, whose occupation as an electrician likely involved high exposure to asbestos. She sought cover for a personal injury caused by inhalation of a foreign object on a specific occasion.

Before she died, ACC declined her claim, reasoning that for cover to be available for mesothelioma, the disease must arise as a result of work exposure. ACC’s decision was upheld on review and by the District Court. However, in the High Court, Mallon J allowed the appeal by Ms Trevarthen’s estate and held that she was entitled to cover under the Accident Compensation Act 2001 because her mesothelioma was a personal injury caused by an accident to her.

On 27 May 2021, the Court of Appeal unanimously ruled that Ms Trevarthen’s non work-related mesothelioma was a personal injury under s 26(1)(a) and (b).

In dismissing ACC's case, the Court of Appeal held that the exclusion provision under s 26(2) did not apply because Ms Trevarthen’s personal injury was not caused wholly or substantially by gradual process, disease or infection.

ACC cover was available to her under s 20(2)(a) because her injury was caused by an accident, which was the inhalation of asbestos fibres.