Karnin Petera, 15, died on a school trip to Abbey Caves on 9 May 2023.
Fourteen students and two adults were rescued from the cave in heavy rain. Karnin's body was later found.
The school had a risk assessment done for the trip that stated Abbey Caves were "prone to flooding" in heavy rain.
It recommended to postpone the trip if water levels were too high.
The trip went ahead, despite Northland being under a MetService orange rain warning.
WorkSafe said the charges had been filed against the legal entity of the Board of Trustees, not individual members of the board.
WorkSafe's head of inspectorate Rob Pope said it acknowledged the "profound impact" Karnin's death had on whānau, friends, and the wider community.
"A year on, our sympathy and thoughts are with all of those who knew and loved Karnin."
An "extensive" investigation had now pieced together the circumstances of the tragedy and charges had been filed in the Whangārei District Court.
"We encourage school boards of trustees across the country to reflect on their own systems and processes to ensure they are meeting legal requirements for education outside the classroom," Pope said.
"Students should be able to participate safely, and parents must have confidence their rangatahi will be kept safe."
WorkSafe has charged the board under sections 36(2), 36(1)(a), 48(1) and 2(c) of the Health and Safety at Work Act 2015.
Charges include:
- Being a PCBU (Person Conducting a Business or Undertaking), having a duty to ensure, so far as is reasonably practicable, that the health and safety of other persons is not put at risk from work carried out as part of the conduct of the business or undertaking, namely the outdoor education caving activity to Abbey Caves Reserve, did fail to comply with that duty, and that failure exposed other persons, including Karnin Petera, to a risk of death or serious injury.
- Being a PCBU, having a duty to ensure, so far as is reasonably practicable, the health and safety of workers who work for the PCBU, while the workers were at work in the business or undertaking, namely undertaking an outdoor education caving activity to Abbey Caves Reserve, did fail to comply with that duty, and that failure exposed workers to a risk of death or serious injury.
