Homeowners and landscaping professionals commonly use herbicides to control weeds and clear land for new gardens or construction. Herbicides are so common and easy to obtain and use that it's easy to forget what they are: toxic chemicals designed to poison and kill plants. Not surprisingly, they can have toxic effects on unintended targets as well, include people, pets and livestock, and non-target plants.
Misuse by People
In 2009, the National Poison Data System reported over 9,000 cases of herbicide poisoning in the United States. The majority of cases involved unintentional poisoning. While many occurred in children under the age of 5, nearly half involved adults over the age of 20, suggesting that many instances of herbicide poisoning come from accidental misuse. Herbicide poisoning resulted in few deaths or serious injuries, but 15 percent of the cases reported by the National Poison Data System required a visit to a health care facility.
Pets and Livestock
When used correctly, herbicides pose very little risk to pets and livestock, according to the Merck Veterinary Manual. Problems tend to occur when herbicides contaminate an animal's feed or water, often because of improper labeling and storage. Herbicides can cause both acute poisoning, usual signaled by digestive symptoms, or chronic health problems. Animal owners should contact a veterinary poison control center for help if they suspect herbicide poisoning.
The data available for both human and animal poisoning incidents suggest that homeowners can avoid most instances of herbicide poisoning by employing basic safety precautions. Read labels carefully, apply only the amount prescribed on the label, and follow all safety precautions. Always store herbicides in their original containers with the labels intact, and keep them away from animal feed and out of reach of children. Do not purchase more herbicide than you need.
Know Your Labels
Product labels in the United States contain signal words that describe the risk of harm from the product. Products labeled "Caution" have the lowest risk of causing harm, while products labeled "Warning" carry moderate risks. Products bearing the signal word "Danger" are most toxic. Always choose the least toxic product.
Even with careful use of herbicides, herbicide drift may move chemicals into waterways or onto nontargeted plants, damaging those plants or harming people and animals that eat them. Drift occurs when the wind carries herbicide droplets or when herbicides evaporate into the air. To avoid herbicide drift, use herbicides on cool days with a light breeze but with wind speeds below 10 mph. Wear protective clothing as recommended on the product label to avoid inhalation or contact with eyes and skin.