Key points
- Poisonous plants that can cause skin irritation include poison ivy, poison oak, and poison sumac.
- Burning poisonous plants may lead to lung irritation.
- Employers and workers can take actions to stay safe.
Overview
Many plants are poisonous to humans when ingested or through skin contact with plant chemicals. The most common problems with poisonous plants arise from contact with the sap oil. Several plants native to the United States can cause an allergic skin reaction. These include poison ivy, poison oak, and poison sumac. Workers may also develop lung irritation from contact with burning poisonous plants.
Any workers who spend time outside are at risk of exposure to poisonous plants. Some jobs include:
- Farmers
- Landscapers and gardeners
- Painters
- Roofers
- Construction workers
- Forestry workers
- Firefighters
Geographic distribution
Poisonous plant species are found throughout the United States (except Alaska and Hawaii).
Types
Identifying poisonous plants
The old saying “Leaves of three, let it be!” is a helpful reminder for identifying poison ivy and poison oak. However, it does not apply to poison sumac, which usually has clusters of 7–13 leaves.
In some species, poison ivy and poison oak may also have more than three leaves. Their appearance may also vary depending upon the species, the local environment, and the season. There may also be common lookalike plants in the same areas.
Poison Ivy
Eastern poison ivy is typically a hairy, ropelike vine with three shiny green leaves budding from one small stem. The leaves may be red in the fall.
Western poison ivy is typically a low shrub with three leaves that does not form a climbing vine.
It may have yellow or green flowers and white to green-yellow or amber berries.
Poison Oak
Poison oak is typically a shrub with three leaves, like poison ivy.
Pacific poison oak may be vine-like.
It may have yellow or green flowers and clusters of green-yellow or white berries.
Poison Sumac
Poison sumac is a woody shrub that has stems with 7–13 leaves arranged in pairs.
It may have glossy, pale yellow, or cream-colored berries.
Symptoms
Symptoms of contact with poisonous plants include:
- Red rash within a few days of skin contact
- Bumps, red patches or streaking, or weeping blisters
- Note: fluids in blisters will not cause blisters to spread on you or others
- Swelling
- Itching
Types of Exposure
Poison ivy, poison oak, and poison sumac release an oil (urushiol) when part of the plant is damaged or burned. When the oil gets on the skin, most exposed people have an allergic reaction (contact dermatitis). Workers can become exposed to urushiol through:
- Direct contact with the plant.
- Indirect contact, such as touching tools, livestock, or clothing that have urushiol on them.
- Inhaling particles containing urushiol from burning plants.
Exposure to an amount of urushiol less than a grain of salt causes a rash in 80-90 percent of adults. The rash may significantly impede or prevent a person from working. Burning these poisonous plants can be very dangerous because the allergens can irritate lungs.
Reducing risk
What employers can do
Employers can protect their workers from poisonous plants by training them about:
- Their risk of exposure to poisonous plants.
- How to identify poisonous plants.
- How to prevent exposure to poisonous plants.
- What they should do if they are exposed to poisonous plants.
What workers can do
Wear long sleeves, long pants, boots, and gloves. Wash exposed clothing separately in hot water with detergent.
Use barrier skin creams, such as a lotion containing bentoquatam which may offer some protection before contact. Barrier creams should be washed off and reapplied twice a day.
Clean tools with rubbing alcohol (isopropanol or isopropyl alcohol) or soap and lots of water. Urushiol can remain active on the surface of objects for up to 5 years. Wear disposable gloves while cleaning.
Do not burn plants that may be poison ivy, poison oak, or poison sumac. Inhaling smoke from burning plants can cause severe allergic respiratory problems.
When burning poisonous plants
Employers should prevent workers from being exposed to burning poisonous plants whenever possible. When exposure to burning poisonous plants is unavoidable, employers should provide workers with a NIOSH-certified half-face piece particulate respirator.
Respirators should be rated R–95, P–95, or better. Firefighters may require a higher level of respiratory protection to protect against possible exposure to combustion products.
Respirators should protect against exposure to burning poisonous plants. However, they will not protect against all products in smoke, such as carbon monoxide.
Respirators must be worn correctly and consistently throughout the time they are used. For respirators to be effective there must be a tight seal between the user’s face and the respirator.
Employers must have a written comprehensive respiratory protection program if workers use respirators (see OSHA Respiratory Protection standard 29 CFR 1910.134).
First Aid
Rinse skin immediately.
- Use rubbing alcohol, poison plant washes, or dishwashing soap, and lots of water.
- Rinse often to prevent wash solutions from drying on the skin and further spreading the urushiol.
Scrub under nails with a brush.
Apply wet compresses, calamine lotion, or hydrocortisone cream to the skin to reduce itching and blistering.
- Follow the directions on any creams or lotions.
- Do not apply creams or lotions to broken skin.
- Oatmeal baths may relieve itching.
Take an antihistamine such as diphenhydramine (like Benadryl) to help relieve itching.
- Follow directions on the package.
- Antihistamines may make you drowsy.
- If children touch contaminated work clothing, contact a pediatrician.
Get medical help in severe cases, or if the rash is on the face or genitals.
Call 911 or go to a hospital emergency room if you or another worker:
- Has a severe allergic reaction, like swelling or difficulty breathing.
- Has had a severe reaction to poisonous plants in the past.
