Accident Compensation Act 2001, s 25

An “accident” means a specific event where your body is subject to some force or resistance outside your body (including when you’re injured in a fall), or where you move suddenly to avoid an external force or resistance, or where you twist your body in some way.

The term “accident” also includes:

• breathing in or swallowing a gas, liquid or foreign object on one specific occasion (long-term exposure at work to harmful substances like asbestos can also be covered under a separate ACC category: see below “Conditions caused gradually: Covered only if work-related”)
• burns, or exposure to radiation or rays on one specific occasion (but usually not sunburn: see below, “What aren’t ‘accidents’?”)
• absorbing chemicals through your skin over a period of up to one month.

The following things aren’t “accidents” and won’t be covered by ACC:

• injuries not caused by any specific event – for example, if you develop muscle pain after a long drive
• injuries like slipped discs that are caused by sneezing or coughing fits (because they’re caused by forces inside your body, not external forces)
• catching common illnesses like colds or flu by breathing in viruses or bacteria
• sunburn, hypothermia and other conditions caused by exposure to the elements (sun, rain, cold, wind and so on), unless your normal activities are restricted by the condition for at least a month
• damage to your teeth or dentures (false teeth) that’s caused by natural use of those teeth or dentures. So if you break a tooth while eating, ACC won’t cover you.

  Note: In the past, ACC had accepted claims if teeth had been damaged by biting on a foreign object that had gotten into food, like a small stone or piece of glass, because they saw this as not being “natural use” of teeth (they wouldn’t accept your claim if it was through biting on something hard that was part of the food, like a piece of bone or a peach stone, as they saw that as “natural use”). However, recent court decisions have taken a narrower approach to “natural use”, and so in 2017 ACC announced there would never be cover for damage to teeth caused by biting on something hard in your food, whether it’s part of the food or a foreign object like a stone.