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NIOSH Safety and Health Topic:Poisonous Plants |
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OverviewMany native and exotic plants are poisonous to humans when ingested or if there is skin contact with plant chemicals. However, the most common problems with poisonous plants arise from contact with the sap oil of several ever-present native plants that cause an allergic skin reaction—poison ivy, poison oak, and poison sumac. Poison ivy, poison oak, and poison sumac release an oil, urushiol, when the leaf or other plant parts are bruised, damaged, or burned. When the oil gets on the skin an allergic reaction, referred to as contact dermatitis, occurs in most exposed people as an itchy red rash with bumps or blisters. When exposed to 50 micrograms of urushiol, an amount that is less than one grain of table salt, 80 to 90 percent of adults will develop a rash. The rash, depending upon where it occurs and how broadly it is spread, may significantly impede or prevent a person from working. Although over-the-counter topical medications may relieve symptoms for most people, immediate medical attention may be required for severe reactions, particularly when exposed to the smoke from burning these poisonous plants. Burning these poisonous plants can be very dangerous because the allergens can be inhaled, causing lung irritation. Outdoor workers may be exposed to poisonous plants. Outdoor workers at risk include farmers, foresters, landscapers, groundskeepers, gardeners, painters, roofers, pavers, construction workers, laborers, mechanics, and any other workers who spend time outside. Forestry workers and firefighters who battle forest fires are at additional risk because they could potentially develop rashes and lung irritation from contact with damaged or burning poisonous plants. It is important for employers to train their workers about their risk of exposure to poisonous plants, how they can prevent exposures and protect themselves, and what they should do if they come in contact with these plants. U.S. Geographic DistributionOne or more of the most common poisonous plant species are found throughout the United States (except Alaska and Hawaii). These plants can be found in forests, fields, wetlands and along streams, road sides, and even in urban environments, such as, parks and backyards. Poison Ivy
Across the United States, except California, Alaska, and Hawaii Poison Oak
Primarily the Southeast and West Coast Poison SumacAbundant along the Mississippi River and boggy areas of the Southeast
Plant IdentificationThe old saying "Leaves of three, Let it be!" is a helpful reminder for identifying poison ivy and oak, but not poison sumac which usually has clusters of 7-13 leaves. Even poison ivy and poison oak may have more than three leaves and their form may vary greatly depending upon the exact species encountered, the local environment, and the season. Being able to identify local varieties of these poisonous plants throughout the seasons and differentiating them from common nonpoisonous look-a-likes are the major keys to avoiding exposure. Poison Ivy
Poison Oak
Poison Sumac
ExposureWorkers may become exposed to urushiol through:
SymptomsSigns or symptoms associated with dermal contact with poisonous plants may include:
Recommendations for Protecting WorkersEmployers should protect their workers from poisonous plants by training them about:
PreventionWorkers can prevent contact with poisonous plants by taking these steps:
Employers should prevent workers from being exposed to burning poisonous plants whenever possible. However, when exposure to burning poisonous plants is unavoidable, employers should provide workers with:
First AidWorkers who have come in contact with poisonous plants should:
Additional ResourcesOccupational Safety and Health Administration � Sawmills eTool: Poisonous Plants
National Library of Medicine/National Institutes of Health � Medline Plus: Poison Ivy-Oak-Sumac Rash
Food and Drug Administration: Outsmarting Poison Ivy and Its Cousins
American Academy of Dermatology: Poison Ivy, Oak, and Sumac
The Poison Ivy Site
Poison Ivy, Oak, and Sumac Information Center
Ohio State University Extension - Poison Ivy, Poison Oak, and Poison Sumac for Trainers and Supervisors
Poison Oak: More Than Just Scratching the Surface
Page last updated:
June 5, 2009
Page last reviewed: October 21, 2008 Content Source: National Institute for Occupational Safety and Health (NIOSH) |
Page last updated: November 12, 2008
Page last reviewed: October 10, 2008 Content Source: National Institute for Occupational Safety and Health (NIOSH) Education and Information Division |
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