Farm Chemicals That Cause Bee Colony Failure and Other Failures

Several highly toxic agricultural chemicals remain legally registered for use in the United States despite being banned internationally or actively under federal review for severe environmental and occupational harm.

Here are the most prominent chemicals currently under intense study that are still legally applied:

Neonicotinoids (e.g., Imidacloprid, Clothianidin)

Application: Systemic insecticides widely used as seed coatings. The chemical is absorbed into the plant's vascular system, making the entire plant (including pollen and nectar) toxic.

Harm Under Study: They are extreme neurotoxins to invertebrates. They are under intense study for driving Colony Collapse Disorder by destroying the homing and navigation systems of bees, and for causing chronic neurotoxicity and reproductive failure in insect-eating birds.

Status: Banned for outdoor agricultural use in the European Union, but they remain the most widely used class of insecticides in the United States.

Atrazine

Application: A broad-spectrum herbicide heavily used on corn, sorghum, and sugarcane to kill broadleaf weeds.

Harm Under Study: It is a potent endocrine disruptor and highly mobile in groundwater. Long-term studies indicate that at concentrations of just parts-per-billion, Atrazine runoff chemically castrates male amphibians, turning male frogs into functioning females by artificially converting testosterone into estrogen.

Status: Banned in the EU in 2004 due to groundwater contamination, but it remains the second most widely used agricultural herbicide in the US.

Dicamba

Application: An herbicide used extensively on genetically modified cotton and soybeans.

Harm Under Study: Dicamba is highly volatile. After application, it can vaporize and drift for miles as a gas ("vapor drift"). It is under study for causing catastrophic damage to non-target farms, native forests, and local broadleaf ecosystems, completely stripping the food sources required by local insect populations.

Status: It has been the subject of massive class-action lawsuits and federal court vacaturs, but the EPA continues to issue localized approvals allowing its ongoing use with certain temperature and wind restrictions.

Glyphosate (Roundup)

Application: The most widely used herbicide in global agriculture, applied to clear fields and dry out crops before harvest.

Harm Under Study: The core scientific dispute surrounds its carcinogenicity. Epidemiological studies have investigated its link to non-Hodgkin’s lymphoma in farmworkers, groundskeepers, and agricultural laborers exposed to heavy, chronic doses.

Status: The World Health Organization’s International Agency for Research on Cancer (IARC) classified it as a "probable human carcinogen" in 2015. However, the US EPA maintains that it is not likely to be carcinogenic to humans, and it remains fully legal and widely used.