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Firefighter Guidance Note: Exposure to Noxious Weeds

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.


Firefighters may come into contact with noxious weeds. Noxious weeds colonize in a wide range of habitats but prefer rich, damp soil found along railroad right-of-ways, roadside ditches, stream banks or other moist areas.


Noxious weeds contain toxic compounds found in the sap of plant stems, leaves and flowers. These toxic compounds may become absorbed by your skin and energized when exposed to ultraviolet light from the sun on both sunny and cloudy days.

You can be exposed through inhalation (breathing), skin contact, eye contact or ingestion (swallowing).

Exposure to these compounds can cause serious rashes, burns or blisters to your skin. Contact with eyes may lead to temporary or permanent blindness. Your airway could swell closed from mucus membrane exposure.

When exposed to fire these plants can be an inhalation hazard as the smoke/fumes emitted can blister your airways and lungs.

Actions for employers

Employers should:

  • assess the potential risk of occupational exposure to noxious weeds
  • do pre-planning by contacting municipal parks and recreation for any known locations of noxious weeds
  • put in place practices to prevent or reduce the risk of exposure at the scene and/or upon return to the station

Some examples of noxious weeds in Ontario

Some common noxious weeds include:

  • wild parsnip
  • giant hogweed
  • poison ivy
  • poison sumac
  • stinging¬† nettle

You can find a complete list of Ontario’s noxious weeds on the Ministry of Agriculture, Food and Rural Affairs website.

Preventing exposure to noxious weeds

Personal protective equipment (PPE) can protect you from exposure to noxious weeds. PPE may include:

  • hand protection
  • eye protection
  • respiratory protection
  • skin protection

You should consider these safety precautions to prevent exposure:

  • wear your full PPE
  • use proper doffing procedures for contaminated gear and equipment
  • bag contaminated PPE and equipment on scene and have it transported outside of the vehicle cab to the station for cleaning
  • wash any exposed skin with soap and cold water as soon as possible
  • seek medical attention if you are exposed to or have any questions about the noxious weeds

Applicable regulations, acts and standards


  • Occupational Health and Safety Act
    • clause 25(2)(a) for providing information and instruction to a worker
    • clause 25(2)(d) for making workers aware of hazards
    • clause 25(2)(h) for taking every precaution reasonable to protect workers


Learn about noxious weeds in Ontario and how to protect workers from them.

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Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.