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How to Protect Outdoor Workers from Hazardous Plants


If your employees perform outdoor work, you must take safety precautions to protect them from hazardous plants.

Contact with hazardous plants, such as poison ivy, poison oak, and poison sumac, can cause allergic reactions. Exposure to some toxic plants, such as giant hogweed, can lead to severe burns and even blindness.

It is critical that your workers know how to identify such hazardous plants, how to prevent exposure and what to do in case they are exposed.

Which occupations are at most risk?

All those who work near vegetation are at risk. These include gardeners, landscapers, farmers, road workers, outdoor recreational or camp workers.

What are some common hazardous plants to watch out for?

Poison ivy, oak, and sumac


(From left) Poison ivy, poison oak and poison sumac

These plants contain a sticky oil (urushiol) that may cause a red, itchy rash called allergic contact dermatitis.

You can get the rash if you:

  • Brush or touch any part of these plants, including leaves, stems, flowers, berries, roots, and even if the plant is dead, or
  • Touch anything that’s been in contact with these plants, such as your clothing, pet fur or gardening equipment.

The rash may cause mild (redness, hives, blisters) to severe (trouble breathing, swelling of face) symptoms.

Poison ivy is common across Canada. Poison oak is found in British Columbia and poison sumac is found in central and eastern Canada.

Giant hogweed

Mature giant hogweed plants produce large, white umbrella-shaped flower clusters.

The sap in the stalk, stems and leaves of the giant hogweed contains photosensitive chemicals that become toxic on contact with sunlight. Exposure to the sap can cause severe burns or blindness. Though the reaction can take place in under 15 minutes, the symptoms may take several hours to appear.

  • Contact with skin may cause it to redden and blister
  • Exposed skin may darken for several months
  • Contact with eyes may cause pain and temporary or permanent blindness.
  • Light sensitivity may be experienced by those exposed for months or years.

Giant hogweed is common across southern and central Ontario, south and central Vancouver Island, the Gulf Islands, and Greater Vancouver.

Employers should refer to the Canadian Poisonous Plants Information System to learn which plants to avoid. Thorns or spines of non-poisonous plants, too, can cause injuries.

What safety precautions should employers take to protect outdoor workers?

Employers should conduct a risk assessment of their work site and put safety controls in place accordingly. The most effective safety control is to train your workers to identify and avoid hazardous plants.

We recommend that you:

  • Provide staff tools and equipment that reduces physical contact with toxic plants
  • Put up warning signs in areas where hazardous plants are located
  • Ask workers to inform supervisors and warn co-workers if they spot hazardous plants at the worksite unexpectedly
  • Ensure your staff wears proper personal protective equipment (clothing, eyewear, face shields, boots, vinyl or leather gloves) while handling or removing hazardous plants, especially giant hogweed
  • Do not use power tools near the plants as it may release the toxic sap or oil
  • Do not use string trimmers to trim poisonous plants as they can spray sap or leaves widely
  • Do not burn the plants. Doing so may put your staff at risk of inhalation exposure, which can cause acute respiratory problems
  • Remind workers to scrub boots and gloves thoroughly with soap and water before carefully removing protective clothing
  • Ask that workers wash their work clothing separately with soap and hot water and hang it out outside to dry for several days
  • Ensure thorough cleaning of all equipment, camping gear and gardening tools that may have come in contact with a toxic plant
  • Provide first aid supplies on site

How to treat exposure to hazardous plants?

Giant Hogweed

  • Get medical attention immediately. In the meantime:
  • Wash the affected skin with degreasing soap and cold water. Also, clean thoroughly under nails with a brush, soap, and cold water.
  • If the sap gets into your eyes, wash them with lots of water. Put on ultraviolet (UV) protective sunglasses.
  • Keep out of all sunlight for at least 48 hours. You will need to cover up and protect affected skin from sunlight using a sun block cream.

Poison ivy, oak, or sumac

  • Wash the affected area with degreasing soap and cold water. Also, clean thoroughly under nails with a brush, soap and cold water.
  • If you experience a severe reaction, such as swelling of the face or difficulty breathing, call 911 immediately
  • You must go see a doctor if you experience a severe rash

For a mild rash:

  • Wash the affected skin with cold water
  • Apply calamine lotion to relieve itching
  • Do not scratch the rash as it may cause an infection
  • Contact a doctor if the rash spreads or your symptoms become severe

Do you need help creating health and safety policies for your workplace?

Whether you need help developing a safety policy for outdoor staff or guidance on making your workplace COVID-secure, our health and safety experts have you covered. To learn more about how our services can benefit your business, call us today at 1 (833) 247-3652.

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