Fast Facts

Atrazine is one of the most studied and thoroughly tested chemicals in the world. More than 7,000 scientific studies, conducted over a span of more than 60 years, have clearly established its safety for humans and the environment. It is widely used in more than 50 countries around the world — in Asia, Africa, Australia, North America, South America and the Middle East — and is supported by sound scientific evidence provided by a range of independent sources, including:

• U.S. Environmental Protection Agency (EPA)
• Joint FAO/WHO Meeting on Pesticide Residues (JMPR)
• United Kingdom’s Scientific Committee on Plants, conducted on behalf of the European Union
• Health Canada Pest Management Regulatory Agency (PMRA)
• Australian Pesticides and Veterinary Medicines Authority (APVMA)

No one ever has, ever will, or ever could ingest enough atrazine in drinking water to adversely affect their health. When used according to the label, atrazine has not and will not negatively affect human health. A 150-pound adult could drink thousands of gallons of water containing 3 parts per billion of atrazine (the EPA standard, which includes a wide, 1,000-fold safety margin) every day for 70 years and still experience no adverse health effects. It is clearly not possible to drink this much water for even a single day. In other words, the limits set by EPA are designed to be highly conservative to protect human health and the Agency is constantly reviewing the science literature to stay up to date on these standards.

All registrants (pesticide companies) involved in an EPA review process are legally required to fund industry studies. Activists routinely dismiss high-quality studies by saying they are "industry funded" and, therefore, should not be trusted. The truth is that all registrants are required by U.S. law to fund stringent, state-of-the-art studies that follow strict and transparent guidelines, so as not to burden the taxpayers with the multimillion-dollar cost. Every aspect of an industry study submitted to EPA in support of product registrations is transparent to the public and authorized, audited and reviewed by EPA. Eliminating industry studies carried out at the behest of EPA and conducted in compliance with Good Laboratory Practice Standards would throw the regulatory process into chaos and increase the direct burden on U.S. taxpayers.

Atrazine products are critical agricultural tools that support land and water conservation, helping to maintain and enlarge the natural habitats of frogs and other wildlife. An estimated 210,000 – 310,000 acres of land can be used for purposes other than crops — such as wildlife conservation — thanks to the gains in productivity that atrazine (and sister herbicide, simazine) provides. Using atrazine and other related triazine herbicides in conservation tillage and no-till farming helps decrease fuel use, improve water quality and reduce soil erosion by up to 85 million tons per year.

The loss of atrazine could wipe out as many as 85,000 U.S. jobs. According to the EPA, farming without atrazine could cost corn growers alone as much as $42 per acre from alternative herbicide expenses and reduced yields from poor pest control. The estimated net social value of triazine herbicides is $3.6 billion to $5.2 billion, including on-farm income, with about 75% of this benefit positively impacting the U.S. economy. Holding crop prices, planted acres and production at their three-year averages from 2016-2018, the estimated net benefits range from almost $2.9 billion to $4.2 billion for U.S. corn growers and $322 million for U.S. sorghum growers. This translates to an annual net economic loss of $3.1 billion to $4.6 billion.

Atrazine has received favorable safety reviews from European Union (EU) and UK regulators — and a sister herbicide (terbuthylazine) very similar to atrazine is widely used by millions of European farmers. Atrazine was not approved by the European Commission for use as a crop protection product based on a conclusion that concentrations of atrazine and its relevant breakdown products would exceed the regulatory threshold of 0.1 ppb (Commission Decision 2004/248/EC). The 0.1 ppb value is a regulatory threshold in the EU that is not based on the actual risk posed to humans or the environment.

The EPA has stated that atrazine and related herbicides pose “no harm” to “the general U.S. population, infants, children … or other major identifiable groups.” Subsequent reviews have repeatedly affirmed these findings. As calculated above, it is clear that no one could ingest enough atrazine in drinking water to adversely affect their health at real-world exposure levels.

In 2007, the World Health Organization reported that atrazine does not cause birth defects, and in 2011 an EPA Scientific Advisory Panel reported that atrazine does not affect reproductive or developmental outcomes, even at levels much higher than would ever be found in the natural environment. This scientific understanding was recently reaffirmed in the 2018 EPA’s Human Health Risk Assessment (HRA).

A 2011 Agricultural Health Study report sponsored by the EPA, the National Cancer Institute and the National Institute of Environmental Health Sciences, confirmed that there is no statistically significant link between the use of atrazine and the incidence of hormone-related cancers, including breast, prostate and ovarian cancer. An EPA Scientific Advisory Panel, as well as the World Health Organization and government agencies in the United Kingdom, Canada and Australia, have reported that available data do not support any association between atrazine exposure and any form of cancer.

In 2007, EPA concluded that "atrazine does not adversely affect amphibian gonadal development based on a review of laboratory and field studies...” In a white paper issued by EPA in 2012 prior to a Science Advisory Panel (SAP), the Agency indicated that it “has been unable to find any clear and consistent effects correlated to atrazine exposures across amphibian species, in spite of the large number of studies that purport that such effects exist…” Based on EPA guidance, two large-scale studies (Kloas, 2009) were conducted in separate laboratories using 3,200 frogs and 100,000 tissue samples to determine whether or not atrazine has an impact on growth, development, survival, or sexual differentiation in frogs. EPA audited and inspected the data from these studies and found: “The data are sufficiently robust to outweigh previous efforts to study the potential effects of atrazine on amphibian gonadal development” and "there is no compelling reason to pursue additional testing."

Furthermore the one study in which all of the identified test design elements were accounted for remains the one that was conducted in response to the DCI [Data Call-In] in 2004, which was comprised of two studies conducted in parallel at two different laboratories. This study did not demonstrate any “consistent, concentration-dependent effects of atrazine on sexual development, metamorphosis, growth and survival of X. laevis [a type of frog] at atrazine concentrations of 0.01 to 100 μg/L.” This concentration range is considered to represent the upper limit of environmentally relevant exposures. In addition, a survey of frog populations in forests, agricultural areas, suburbs and cities in the U.S. Northeast found that frogs were thriving in rural, agricultural communities, while frogs in cities and suburbs had much higher deformity rates. A similar survey conducted by Prof. Tyrone Hayes of University of California, Berkeley with scientists at the U.S. Geological Survey, of the native northern leopard frog shows that it continues to thrive in areas where atrazine is heavily used, including in irrigation ditches next to cornfields in the U.S. Midwest. Collectively, the extensive body of research indicates that atrazine does not adversely affect fish, amphibians and reptiles at environmentally relevant concentrations (<100 mg atrazine/L) when considered under a Quantitative Weight of Evidence (QWoE) framework (Van Der Kraak et al., 2014; Hanson et al., 2019).

The EPA Human Health Risk Assessment confirmed that atrazine cannot and does not disrupt the human endocrine system at levels to which people could ever be exposed in the natural environment. In 2017, EPA conducted an updated systematic review of published epidemiology studies to investigate the evidence of human health effects associated with exposure to atrazine. EPA concluded that: “Overall, we considered the epidemiological evidence to be limited but insufficient at this time to conclude that a clear associative or causal relationship between atrazine exposure and the carcinogenic and noncarcinogenic health outcomes in the studies reported here.”