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VENTILATION of parking areas

Enclosed or underground car or bike parks require adequate ventilation to prevent the build-up of toxic gases.

Carbon monoxide is a poisonous gas emitted by operating petrol, gas and, to a lesser extent, diesel-powered motors. Being colourless, tasteless and odourless, carbon monoxide build-up to dangerous levels can go undetected in poorly ventilated spaces.


  • Good ventilation is essential in underground car and bike parks.
  • Turn your car engine off once you park.
  • Close windows while in a car park.

Potential harm

  • Headaches
  • Impaired motor skill
  • Breathing difficulties

Identified hazards and controls

Exposure to build-up of carbon monoxide


  • Inadequate ventilation in car park.

What workers can do

  • Be aware of dangers and keep your exposure level to a minimum, such as keeping your windows closed.
  • Do not leave your car idling once you are parked.
  • Although gas motors using LNG or LPG produce significantly less carbon monoxide than petrol motors, you still need to exercise caution, particularly in poorly ventilated areas.
  • Diesel motors produce much less carbon monoxide then either petrol or gas. They are less of a problem because toxic diesel exhaust gases are unpleasant to inhale and more easily identified and remedied. However, diesel motors should not be run continuously in poorly ventilated or enclosed areas.

What employers can do

  • Ensure the car park is well ventilated either by natural air movement or mechanical ventilation.
  • If you, as the employer, are not the owner or manager of the car park, discuss safety issues with the car park owner.

More information




Page last reviewed: 25 April 2021

Comcare (Office Safety tool)
GPO Box 9905, Canberra, ACT 2601
1300 366 979 |

Date printed 21 Apr 2024