tractor on field

In agriculture, personal protective equipment such as air-purifying respirators, powered air purifiers, gas masks and air-supplied respirators are crucial for preventing long-term damage.  

However, these tools are just the first lines of defence against toxic gases. It is important to know what kinds of poisonous substances you work around so you can identify symptoms and warning signs:


Hydrogen Sulphide (H2S)

  • Has a distinct rotten egg smell, is extremely flammable and is heavier than air
  • Workers exposed to the gas even for a short time become immune to the odour.
  • Symptoms include eye and respiratory tract irritation, headache, nausea and dizziness.
  • Causes death at high concentrations

Ammonia (NH3)

  • Colourless gas with a distinct, pungent odour that is heavier than air
  • Causes eye and respiratory tract irritation as well as ulceration to the eyes in high concentrations

Carbon Dioxide (CO2)

  • Common sources in agribusiness are soil, plant and animal respiration as well as microbial respiration in manure
  • Acts as an asphyxiant by replacing oxygen in the air, which is especially dangerous to both humans and animals in confined spaces or poorly ventilated buildings
  • Odourless and difficult to detect
  • Early symptoms are dizziness and shortness of breath.

Methane (CH4)

  • Odourless and lighter than air
  • Accumulates on top of manure pits
  • Main hazard is its ability to easily ignite and explode

Nitrogen Dioxide (NO2)

  • Sharp, biting odour and red-brown in colour, but only visible at very high concentrations
  • Extremely toxic, but easily detected by smell
  • Present at the bottom of enclosed spaces
  • Symptoms include bronchitis, pneumonia, and lung damage



Find out more:

This list is not exhaustive. Download your own copy of our “Agriculture Employee Safety Manual” for more ways to keep your agribusiness employees safe: