Animal and insect safety Seasonal safety: Summer

Don't touch!

An outdoor worker’s guide to hazardous plants and animals

Photo: Sherry Smith/iStockphoto

If you work outdoors, especially on jobsites that are new to you, biologist Stephanie Pendergrass has some advice: Do your research on the local plants and animals.

“Contact the local forest service office, local university biology or botany department, city parks department and/or the county agriculture extension office,” said Pendergrass, of the NIOSH Division of Science Integration.

Last year, the nation’s 55 poison control centers fielded nearly 2.1 million calls, according to Julie Weber, director of the Missouri Poison Center and chair of the American Association of Poison Control Centers’ board of directors. Many involved encounters with poisonous plants and venomous animals – common summertime hazards that anyone who works outdoors should be aware of.

Poisonous plants

When it comes to poisonous plants, encounters with poison ivy, poison oak and poison sumac generate the most calls to the nation’s poison control centers. Others include stinging nettle, giant hogweed and hemlock.

“If it’s an irritant on the skin, you can start out with a red, itchy rash,” Weber said of the symptoms workers may experience when coming in contact with these plants. “But it can progress to blistering and swelling and more irritation.”

In addition, lung irritation can occur when smoke from burning plants is inhaled. Workers at risk include those in agriculture, forestry, landscaping and groundskeeping, and construction, as well as painters, roofers and others who spend time outdoors.

Pendergrass recommends that employers have cleaning supplies onsite, including soap and water, alcohol disinfectants, and hand wipes. Anyone with known allergies should be provided personal protective equipment, assigned to other duties with less exposure risk, or provided quicker response to exposures and access to treatment, she added.

NIOSH has a webpage about poisonous plants, and the U.S. Department of Agriculture's online resource features a searchable list of invasive and noxious plants by state or name.

Among the most common:

Poison ivy, oak and sumac: Around 85% of people exposed to these plants will develop an allergy, OSHA says. These plants, which contain poisonous sap in their roots, leaves and stems, can cause lung irritation if burned and the smoke is inhaled.

Poison ivy and oak, NIOSH notes, can be easily identified by their three green leaves from one stem. Remember: “Leaves of three, let it be.” In some cases, poison oak can have up to five leaves. Meanwhile, poison sumac is a woody shrub that has seven to 13 leaves, often arranged in pairs.

Stinging nettle: Also known as wood nettle, this plant can irritate the skin with its stinging hairs. This makes gloves and long-sleeved shirts a must. Its leaves and stems contain irritants, says the Missouri Department of Conservation, which adds that the leaves have coarse edges. 

Giant hogweed: When the toxic sap of this plant comes in contact with a worker’s skin and then is exposed to sunlight, it can cause severe skin inflammation known as phytophotodermatitis. This reaction can begin as soon as 15 minutes after contact, the New York State Department of Environmental Conservation says.

Cutting brush can cause the sap to splatter as the plant’s stems are cut. In some cases, these plants – which can grow more than 12 feet tall, feature stalks with dark purple blotches and produce numerous white flowers – can cause permanent blindness if their sap gets into your eyes. Wear eye protection.

Hemlock: Featuring white flowers in umbrella-shaped clusters, this plant’s leaves resemble those of a fern, the National Park Service says. It can grow up to 10 feet high and has a musty odor. The plant’s toxicity can affect people’s nervous system and cause tremors, paralysis and breathing difficulties. Muscle damage and kidney failure may occur in severe cases.

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