Regulatory Timeline

  • 1959

    U.S. regulators approve atrazine.

  • Late 1980s

    Atrazine classified as “possible human carcinogen” after research on one species of rat.

  • Early 1990s

    Atrazine in the environment drops significantly after stewardship programs introduced.

  • 1994

    EPA initiates the Special Review of the Triazine Herbicides, leading to an EPA Special Advisory Panel to review safety of triazine products, reviewing hundreds of studies and more than 80,000 public comments.

  • 1998

    World Health Organization’s International Agency for Research on Cancer (IARC) re-catergorizes atrazine as “not classifiable as to carcinogenicity in humans.”

  • 2000, 2001

    An EPA Special Advisory Panel, then the full EPA, say atrazine is not likely to cause cancer, after finding the 1980s research used was not relevant to humans.

  • 2003

    EPA’s Interim Re-registration Eligibility Decision reconfirms the safety of atrazine, after public forums, tens of thousands of public comments, and input from environmentalists, manufacturers and consumers.

  • 2003

    After reviewing dozens of studies, including four by Prof. Tyrone Hayes, EPA Science Advisory Panel rules evidence inconclusive on whether atrazine exposure affects amphibian life.

  • July 2004

    Shortly after EPA’s 2003 Interim Re-registration Eligibility Decision reconfirming the safety of atrazine, the trial attorney firm of Korein Tillery files the Holiday Shores class action lawsuits in Madison County Illinois seeking damages against the makers of atrazine.

  • 2006

    EPA releases Triazine Cumulative Risk Assessment, finding triazine herbicides (one of which is atrazine) pose “no harm that would result to the general U.S. population, infants, children, or other consumers.”

  • April 2006

    EPA issues atrazine re-registration decision saying “levels of atrazine that Americans are exposed to in their food and drinking water are below the level that would potentially cause health effects.”

  • October 2007

    EPA concludes atrazine does not affect amphibian development; says “no additional testing is warranted…”

  • 2007

    EPA issues White Paper on recent amphibian research, saying there is “no compelling reason to pursue more testing” on the question of the effect of atrazine on amphibian life.

  • 2007

    Independent Science Advisory Panel meets to review and comment on the ecological monitoring program for atrazine.

  • 2007

    A joint meeting of the Food and Agricultural Organization and the World Health Organization on pesticide residues concludes that atrazine is not likely to pose a risk of cancer to humans.

  • August 20, 2009

    Tyrone Hayes submits “Atrazine induces complete feminization and chemical castration in male African clawed frogs” to the Proceedings of the National Academy of Sciences (PNAS) for publication

  • August 22, 2009

    New York Times article “Debating how much weedkiller is safe in your water glass” is published. Also, the Peoria Journal Star (Ill.) publishes “Lawsuit questions safety of herbicide”

  • August 23, 2009

    Huffington Post Investigative Fund website publishes “EPA Fails to Inform Public About Atrazine”  with an accompanying video

  • August 24, 2009
    After national media outlets provide articles touting the report, National Resources Defense Council (NRDC) releases its report “Poisoning the Well”
  • September 16, 2009

    Holiday Shores Sanitary District adds additional plaintiffs to Madison County, Illinois, lawsuit

  • October 7, 2009
    EPA announces “comprehensive new evaluation of atrazine”; Daily Environment Report reports “EPA said the evaluation was sparked by information contained in a Natural Resources Defense Council report and news reports on atrazine contamination of drinking water”
  • November 3, 2009

    EPA holds meeting to “present SAP its plan for the new atrazine evaluation”

  • 2009

    EPA announces a new re-evaluation of atrazine with six Scientific Advisory Panels.

  • January 5, 2010

    Pesticide Action Network (PANNA) and Land Stewardship Project (of Minn.) release “The Syngenta Corporation and Atrazine: The Cost to the Land, People and Democracy”; groups submit letter from organic farmers to EPA

  • January 15, 2010

    State of Minnesota announces “atrazine regulations protect human health and the environment.”

  • January 15, 2010

    More than 50 agricultural groups send letter to EPA Administrator Lisa Jackson in support of atrazine

  • February 2-5, 2010

    EPA convenes Scientific Advisory Panel (SAP) on reviewing epidemiology in regulatory risk assessments

  • February 5, 2010

    University of Washington epidemiology study released on environmental connection between atrazine and birth defects

  • February 23, 2010

    Hayes invited to speak to committee of Illinois state legislature

  • March 2010
    Wisconsin bill to ban atrazine introduced/withdrawn
  • March 1, 2010

    Hayes study published in PNAS

  • March 8, 2010

    Huffington Post Investigative Fund publishes “Cities Sue Manufacturer of Weed-Killer Found in Tap Water”

  • March 8, 2010

    Federal class action lawsuit filed in Southern District of Illinois

  • March 18, 2010

    Hayes invited to speak at Illinois State University

  • March 25, 2010

    Federal suit adds additional plaintiffs

  • April 19, 2010

    New York State Sen. Alesi (R-Perinton, Monroe County) introduces bill to ban atrazine

  • April 21, 2010

    33 members of Congress sign and submit letter to EPA Administrator Lisa Jackson in support of atrazine

  • April 22, 2010

    Rep. Ellison (D-MN) introduces federal bill to ban atrazine

  • April 23, 2010

    EPA announces new SAP on possible cancer effects of atrazine

  • April 26-29, 2010

    EPA convenes SAP on animal studies and water monitoring

  • April 30, 2010

    “Save the Frogs Day” introduces petition to ban atrazine; threatens “International Day of Pesticide Action” and march on Washington this year on October 24

  • May 3, 2010

    NRDC releases “Still Poisoning the Well”

  • May 5, 2010

    University of Illinois releases study saying “without alternatives, atrazine elimination would severely compromise sweet corn production”

  • May 5, 2010

    Report from Agricultural Health Study says “no correlation between atrazine and cancer”

  • May 13, 2010

    President’s Cancer Panel releases report including section on atrazine, including quotes from Hayes

  • 2013

    EPA initiates routine Registration Review of atrazine.

  • May 27, 2014

    Papoulias Medaka Study – Conducted in 2004 but not published until 2014, this questionable study indicates detrimental impact of atrazine to medaka fish, which has not been found in other studies. Study was not submitted during several recent EPA Science Advisory Panels. Read more

  • September 12, 2014

    Sadinski, Hayes Amphibian Study – Dr. Tyrone Hayes coauthors a study that shows frogs in the Midwest where atrazine is used are actually thriving, disproving his theory that atrazine is detrimental to frogs.
    Read more

  • April 29, 2016

    EPA posts a signed Refined Ecological Risk Assessment for Atrazine report dated 4-12-16, on the EPA website recommending an aquatic life “Level of Concern” (LOC) of 3.4 parts per billion, dramatically lower than the 10 ppb LOC currently being used by EPA.

  • May 3, 2016

    EPA removes the 1,100-page Refined Ecological Risk Assessment for Atrazine report dated 4-12-16, on the EPA website recommending an aquatic life “Level of Concern” (LOC) of 3.4 parts per billion, dramatically lower than the already low 10 ppb LOC currently being used by EPA. EPA officials said the report was posted accidentally and said it would be released in a few months.

  • June 6, 2016

    EPA released its Ecological Risk Assessment for atrazine. In its recommendations, EPA ignored several high-quality studies and instead used studies the agency’s own 2012 Scientific Advisory Panel (SAP) found to be flawed. Using the flawed research, EPA recommended the aquatic life level of concern (LOC) be set at 3.4 parts per billion (ppb) on a 60-day average. EPA’s current LOC for atrazine is 10 ppb, however all credible scientific evidence points to a safe aquatic life LOC at 25 ppb or greater.

  • October 4, 2016

    Comment period ends for the Ecological Risk Assessment for atrazine. Over 77,000 comments were received by EPA.

  • July 24, 2018

    EPA releases the Cumulative Human Health Risk Assessment for atrazine as part of the registration review process. EPA is accepting comments through September 24. EPA continues to comb through the comments from the Ecological Risk Assessment from 2016.

  • September-November 2018

    EPA Grants Triazine Network request to extend the Human Health Risk Assessment comment period to Nov. 23, 2018. Growers and farm organizations submit comments to EPA.

  • 2019

    Growers and the Triazine Network hold several meetings with EPA to help the agency understand the importance of atrazine to farming and conservation practices, as well as the need to “get the science right” in the atrazine registration review. See actions here

  • Jan. 2, 2020

    EPA publishes the Preliminary Interim Decision for the atrazine registration review in the Federal Register. Read more here.