history of cpfs blog
Margaret Reeves

Margaret Reeves

Persistence & partnerships: Winning the chlorpyrifos battle

2021 Update: In May, San Francisco’s 9th District Court ordered the Environmental Protection Agency (EPA) to follow its own science and get chlorpyrifos off the market for good. EPA had a small window to request a rehearing by the court, but did not do so.  Instead they opted to remove all tolerance levels for chlorpyrifos in food in August of 2021.  In other words, this set the standard that there cannot be any residue of this pesticide on food.  Since that time, the EPA has been taking and processing voluntary removals of registration for chlorpyrifos products on food crops. Unfortunately, this ban did not include non-food uses.

2023 Update: In November, the 8th Circuit Court of Appeals reversed EPA’s ban on the neurotoxic pesticide chlorpyrifos. In rolling back this ruling, the 8th Circuit Court will open the market for chlorpyrifos to be used in food production starting in 2024 — which will continue until the EPA reinstates the ban.  We encourage you to take action and tell the EPA to reestablish the ban of chlorpyrifos on food crops.  Once that is complete, we can move to complete remove this dangerous pesticide from all uses.


After 20 years of focused work with many partners across the US and around the world, chlorpyrifos is on its way out. As we celebrate and build on each victory, we’re taking a moment to reflect on the decades of multi-faceted, collaborative efforts to win policies that protect workers, children and rural communities from the well-known hazards of this commonly used insecticide. 

It was back in 2000 that the U.S. Environmental Protection Agency (EPA) banned use of chlorpyrifos in homes, explicitly because of its hazards to children’s developing brains. PAN joined with our partners to press for a ban of agricultural uses as well — eliminating its widespread use on farms where it continues to threaten the health and well-being of hundreds of thousands of farmworkers, children and rural communities throughout the country.

However, the pushback from Dow Chemical (now renamed Corteva) and its cronies has proven formidable, as the chemical corporation pulled out all the stops to keep chlorpyrifos on the market. Over the past 20 years, we have faced a rollercoaster of wins and progress mixed with setbacks and frustrations as we’ve approached this issue from all angles. Meanwhile, the scientific evidence of just how harmful chlorpyrifos is to human health and the environment has continued to mount. Here are a few highlights of the policy work, community organizing, grassroots science and storytelling that PAN and partners have undertaken over the last two decades to protect communities from brain-harming chlorpyrifos:

  • 2000–2005: PAN and partners produce two reports (Fields of Poison 2002 and Chemical Trespass) documenting exposures to pesticides — including chlorpyrifos — among farmworkers and children, respectively.
  • 2007: PAN and our partners at the Natural Resources Defense Council file a legal petition against the U.S. EPA calling for a full chlorpyrifos ban, represented by the attorneys at Earthjustice.
  • 2004–2008: PAN conducts several air monitoring projects in California farmworker communities and elsewhere, using PAN’s signature Drift Catcher. The data documenting chlorpyrifos drift into participants’ yards and neighborhoods, together with biomonitoring data we collected tracking chlorpyrifos in people’s bodies, helped build strong community engagement in efforts to improve worker and community protections. This work was done in collaboration with the statewide coalition Californians for Pesticide Reform (CPR).
  • 2015: At the end of the Obama administration, EPA follows advice of its own scientists and proposes a ban on all food uses of chlorpyrifos in response to the original 2007 lawsuit.
  • 2017: The Trump administration’s EPA reverses the planned chlorpyrifos ban. PAN joins seven states and a dozen health and labor groups challenging EPA’s decision in court, and calling, again, for a national ban on all uses of the pesticide.
  • January 2018: No-spray buffer zones around schools and other sensitive sites goes into effect in California, a direct result of the Drift Catching project and other organizing with CPR as noted above.
  • June 2018: In the face of EPA’s inaction, Hawaiʻi becomes the first state to ban use of chlorpyrifos. Encouraged, in the following months, several other states introduce their own bills to ban chlorpyrifos, including Maryland, Oregon and New York.
  • August 2018: The 9th Circuit Court of Appeals rules that EPA must ban chlorpyrifos, and orders the agency to finalize its proposed ban based on undisputed findings that the pesticide is unsafe for public health, and particularly harmful to children and farmworkers.
  • January 2019: Congresswoman Nydia Velázquez (D-NY) reintroduces her bill to ban chlorpyrifos in the House of Representatives, and Senator Tom Udall (D-NM) reintroduces a bill in the Senate. Both receive good support.
  • May 2019: California’s governor announces plans to cancel chlorpyrifos registration and for $5.7 million in state funding to support transition to safer, more sustainable alternatives. PAN is invited to sit on a newly created work group to identify, evaluate and recommend alternative pest management solutions.
  • August 2019: Senator Mazie K. Hirono (D-HI), Tom Udall (D-NM), and 13 Senate colleagues send a letter to EPA Administrator Andrew Wheeler urging him to ban chlorpyrifos. Representative Velázquez and colleagues send a similar letter from the House. PAN and many partners sue EPA again, demanding immediate action. Six states sue the agency as well.

Throughout these two decades, PAN staff scientists worked with partners around the country to review and amplify a wealth of scientific literature on exposures and health hazards directly experienced in farmworker communities and by consumers of pesticide-tainted food. 

During this long process, the voice of farmworkers and rural families has remained front and center with a constant drumbeat of stories — of routine exposures, inadequate protections and direct health impacts — presented online, in the press and in person at state legislative briefings and federal government offices.  

Today, we cautiously celebrate the wave of chlorpyrifos-related policies that have resulted from all those efforts and the brilliant, persistent, and tenacious work of attorneys and organizers from several organizations that have helped make it happen. Collaboration with our partners at Earthjustice, for example, helped win the ear of representatives in Congress — with chlorpyrifos ban bills introduced in both the House and Senate — and helped convince judges in San Francisco’s 9th District Court to order EPA to finalize the ban. As evidenced above, these strong moves today are the culmination of a process that began back in 2000. While our work isn’t done, we’re taking a moment to celebrate these milestones, as well as the persistent and creative advocacy behind them.

Margaret Reeves

Margaret Reeves

Margaret Reeves is a PAN Senior Scientist with expertise in agroecology and soil ecology. As a long-time farmworker advocate, Margaret serves on the Board of the Equitable Food Initiative and works with partners around the country to ensure worker-protective federal and state policy. Follow @MargaretatPAN

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