Poisonous Plants: Types of Exposure

Types of Exposure

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. Burning these poisonous plants can be very dangerous because the allergens can be inhaled, causing lung irritation.

Workers may become exposed to urushiol through:

• Direct contact with the plant
• Indirect contact, such as touching tools, livestock, or clothing that have urushiol on them
• Inhalation of particles containing urushiol from burning plants