Herbicide Toxicity


Herbicides are any substance used to kill or reduce the population of weeds in the home garden or landscape. Herbicides generally refer to synthetic chemicals. Herbicides exhibit different levels of toxicity in the environment to people, animals, plants and the ecosystem at large. Understanding the toxicity and proper use of herbicides will reduce injury.

Prevelance of Dangerous Herbicides

According to the University of Florida Extension, although there are herbicides used in the past that were incredibly dangerous to use, most of these chemicals are now off the market. Herbicides are required to submit their chemicals to the Environmental Protection Agency before they are sold to the public. Herbicides that are dangerous to apply are handled by certified professionals and not sold to the general public.

Choosing Herbicide

Choosing the correct herbicide prevents injury to plants, animals and humans by avoiding misapplication. Low volatile esters--organic chemical compounds--are available that reduce potential for injury. Choosing the least toxic chemicals available reduces poisoning potential. University of Florida Extension says some herbicides are persistent and will not break down quickly enough to allow another crop to be planted in the weed's former spot.

Herbicide Types

Chlorophenoxy herbicides are the oldest herbicides available, making their first appearance in the 1940s. They cause twisting of the plants they come in contract with and destroy younger tissue. They are regarded as generally safe in terms of short-, mid- and long-term side effects. Arsenical herbicides are an old group of herbicides, around since the 1950s. These herbicides are available now in three forms, cacodylic acid, disodium methanearsonate, and monosodium methanearsonate (DSMA and MSMA). Most aresenic herbicides are discontinued due to their high toxicity. Bipyridylium herbicides are also from the '50s and are nonselective in nature, meaning they damage all plants they come in contact with. Diquat and paraquat are the most common forms available. They are moderately toxic when digested, and may cause nervous system damage.


To prevent herbicide poisoning, chemicals are best sprayed on days where the weather is calm and there is light to no wind, and no rain. Herbicides are applied according to the instructions on the label of the chemical. Instructions are best left unmodified. Long clothing is worn to prevent the herbicide from coming in contact with the skin. A respirator prevent herbicides from burning the nose, mouth and lungs.


Leaking containers are disposed of according to the EPA guidelines, or local guidelines for disposal. Leaking containers are never transported in a car or truck, as this may lead to long term contamination of the vehicle. Unused liquids are disposed of according to local guidelines, or stored in a locked area where children and animals have no access.

Keywords: Herbicide toxicity, Using herbicides, Poisonous herbicides

About this Author

Cleveland Van Cecil is a freelancer writer specializing in technology. He has been a freelance writer for three years and has published extensively on eHow.com, writing articles on subjects as diverse as boat motors and hydroponic gardening. Van Cecil has a Bachelor of Arts in liberal arts from Baldwin-Wallace College.