Accident Compensation Act 2001, s 30
In general ACC doesn’t cover conditions, diseases or infections that are caused gradually, rather than by a specific event. However, there are some exceptions to this, and a key one is when you’re exposed to something harmful at work over a period of time and as a result you develop a disease or infection or a condition like hearing loss or repetitive strain injury (RSI). For your claim to succeed you’ll have to show that:
your work tasks or work environment had a particular characteristic (like the presence of a harmful substance, or loud noise) that caused the harm, and
this characteristic isn’t found to any real extent outside your work, and
the risk of suffering the harm is significantly greater for people who do your particular work tasks or have your particular work environment than it is for other people.
Note: For some specific occupational diseases, you don’t have to prove that your work tasks or environment were the cause. These diseases include conditions caused by asbestos, lead, arsenic or mercury. Here you only have to show that your job exposed you to the particular substance.
Because conditions that are caused gradually are only covered if they’re work-related, this means ACC won’t cover you if you develop a condition like RSI or hearing loss from a hobby or other activity in your non-work life.
Illnesses and infections are also covered if they were caused by medical treatment (see below, “Injuries caused by medical treatment: ‘Treatment injuries”). Otherwise, illnesses and infections aren’t covered by ACC.