Confined spaces: Safety basics

Occupational health and safety law has special requirements about working in confined spaces.


What is a confined space?

A confined space is an enclosed or partly enclosed space that has other features that combine to make it potentially dangerous to work in. For example, it's hard to get in and out of, and it may have low oxygen levels, or contain harmful fumes. It may store something that could crush or suffocate, like sand or grain.

Examples of potential confined spaces:

  • storage tanks, tank cars
  • process vessels, pressure vessels
  • silos
  • pits and degreasers
  • pipes, sewers, sewer pump stations
  • wet and dry wells, shafts and tunnels
  • ship cargo tanks, ballast or oil tanks, and void spaces

Risks of working in confined spaces

There are serious health and safety risks working in confined spaces. For example:

  • loss of consciousness, injury or death from contaminants in the air
  • a fire or explosion that kills or seriously injures
  • suffocation from oxygen deficiency
  • crushing or suffocation from something like grain, sand, flour or fertiliser if you fall into it

Incidents in confined spaces have sometimes involved multiple deaths. Other workers enter a space to rescue a victim, unaware of the risks. But they can also be overcome by toxic fumes or gases.

Managing safety in confined spaces

The Confined spaces compliance code has information to help you check if you have any confined spaces, and contains details about hazards, risks and controls.

If you have enclosed spaces that aren’t technically confined spaces, they can still be dangerous. For example, you should evaluate the safety of using an LPG forklift in an enclosed cool storeroom.


Involving your employees in health and safety issues can result in a safer workplace. That's why consultation is an important part of risk management. In certain situations employers must consult about health and safety issues with employees and health and safety representatives (HSRs) if they have them.

Find the hazards

If you have a confined space, you must identify all the hazards associated with work in that space. This might include things like ignition hazards from open flames, and environmental hazards like heat or damp.

Assess the risks

Once you have identified the hazards, you must assess the risks associated with the hazards.

Testing the atmosphere helps you know what hazards are present so you can control the risks in the confined space. It tells you oxygen levels, and if there are air contaminants, flammable gases or vapours. Testing is important because many toxic gases can’t be seen or smelled.

Control risks

The best solution is to eliminate the risk by finding a way to do the work without entering the space. For example, you might be able to clean a tank with a high-pressure hose through the hatch.

If it's not possible to do the work from outside, look at ways to reduce the risk. For example, you could scrape the surface of a tank instead of using chemicals or replace a flammable solvent with a non-flammable one.

Review risk controls

Review your risk controls to make sure they are working properly. You must review and, if needed revise them if, for example:

  • a notifiable incident occurs
  • the risk controls do not control the risk effectively
  • an HSR requests.

Legal duties

The Occupational Health and Safety Act 2004 sets out duties in relation to health and safety in the workplace. The Occupational Health and Safety Regulations 2017 also have specific duties about confined spaces (including purging or ventilation of any contaminants in the atmosphere of a confined space). See the Compliance code: Confined spaces for full detail of duties for:

  • employers
  • self-employed people
  • employees
  • designers, manufacturers and suppliers of plant (machinery and equipment)