Hawaii’s Pesticide Fight: Seed Companies, the 2018 Chlorpyrifos Ban, School Buffer Zones, and Children’s Health

Hawaii became a battleground over pesticides in the 2010s. The islands’ year-round growing season made them a hub for seed companies testing and producing genetically engineered corn and other crops, with frequent pesticide applications near homes and schools on Kauai, Oahu, Maui, and Molokai. Residents, physicians, and community groups raised concerns about health effects, especially on children. Public meetings were often tense; reports described large numbers of seed company employees attending events where doctors and residents spoke about pesticide risks, reflecting how divided communities had become over jobs, agriculture, and health.

The debate produced concrete policy changes, most notably a 2018 state law that banned the insecticide chlorpyrifos and required buffer zones around schools and public reporting of restricted-use pesticides. This article explains what happened in Hawaii, what research shows about chlorpyrifos and children’s health, and where the debate stands in 2026.

Why is Hawaii a center of the pesticide fight? Hawaii’s year-round growing season made it the main U.S. site for testing and producing genetically engineered seed, concentrating heavy use of restricted pesticides near homes and schools. After community concern over drift and children’s health, the state passed Act 45 in 2018, banning chlorpyrifos and creating school buffer zones, a landmark in U.S. pesticide regulation.

Why Did Hawaii Become a Pesticide Battleground?

Hawaii’s year-round climate drew seed companies that used the islands to test and grow genetically engineered crops, leading to intensive use of restricted-use pesticides close to communities. From the 1990s, seed companies including Monsanto, Syngenta, Dow AgroSciences, DuPont Pioneer, and BASF leased land on former sugar and pineapple plantations in Hawaii to develop and multiply seed, particularly genetically engineered corn. The warm climate allowed several crop cycles per year, accelerating breeding. Test fields often required frequent pesticide applications, some involving restricted-use pesticides that require certified applicators because of their potential hazards. On Kauai’s west side, fields lay near schools, homes, and hospitals. Residents reported odors, illnesses, and concerns about drift, and physicians raised questions about birth defects and children’s health, though state investigations did not establish clear links. The companies said they followed label requirements and that their operations provided jobs in rural areas.

Kauai’s Bill 2491 and the Voluntary Program

In 2013, the Kauai County Council passed Bill 2491, which required large agricultural operations to disclose pesticide use and establish buffer zones near schools, hospitals, homes, and waterways. The Honolulu Star-Advertiser reported that, as legal challenges proceeded, five companies, Syngenta, DuPont Pioneer, BASF, Dow AgroSciences, and Kauai Coffee, began following a voluntary state program to disclose pesticide use and establish buffer zones, which law supporters criticized as weak because it was voluntary and its minimum 100-foot buffers were smaller than those in the county law. Seed companies sued, and a federal court ruled in 2014 that the county law was preempted by state pesticide law, a decision later upheld on appeal. Similar county measures on the Big Island and Maui met comparable fates.

What Does Hawaii’s 2018 Pesticide Law Do?

Act 45, passed in 2018, made Hawaii the first U.S. state to ban chlorpyrifos (fully by 2023), required buffer zones around schools, and mandated public reporting of restricted-use pesticide applications. After county measures were struck down, advocates turned to the state legislature. According to The Garden Island, Act 45, signed by Governor David Ige in 2018, banned the use of chlorpyrifos, with a permit system during a phase-out and a full ban from January 1, 2023; it also required 100-foot buffer zones around schools and annual reporting of restricted-use pesticide use to the state Department of Agriculture. The newspaper noted that the state’s approach was the opposite of the federal EPA’s decision at the time not to ban chlorpyrifos, and that state agriculture officials had raised concerns about having the budget to implement all of the law’s requirements.

West Hawaii Today reported that in 2019 the EPA and the Hawaii Department of Agriculture reached an informal resolution agreement, following a civil rights complaint filed by community groups represented by Earthjustice, that directed the department to implement restricted-use pesticide reporting, annual public disclosure, maps of school buffer zones, permits for chlorpyrifos during the phase-out, and public notice of the chlorpyrifos prohibition.

Act 45 provision	What it requires
Chlorpyrifos ban	Permits during phase-out; full prohibition from January 1, 2023
School buffer zones	No restricted-use pesticide application within 100 feet of schools during school hours
Use reporting	Users of restricted-use pesticides report annually to the state
Public disclosure	State publishes aggregated restricted-use pesticide data

The Kauai Worker Exposures

Concerns about pesticide safety were heightened by incidents at seed company farms. Honolulu Civil Beat reported that in January 2016, 19 workers entered a field of genetically engineered corn at Syngenta’s Kekaha farm on Kauai before the required waiting period after it had been sprayed with a chlorpyrifos product, without protective gear; the company decontaminated 35 workers who had shared transportation, and ten were taken to the hospital, three held overnight. The Hawaii Tribune-Herald reported that the EPA alleged violations in January 2016 and January 2017, including failure to notify workers and provide adequate decontamination and prompt medical transport, and that Syngenta agreed to pay a $150,000 civil penalty and spend $400,000 on worker protection training. Critics noted the EPA had initially proposed a fine of about $4.8 million for the 2016 incident alone.

How Does Chlorpyrifos Affect Children?

Cohort studies have linked higher prenatal exposure to chlorpyrifos, an organophosphate insecticide, with lower IQ, poorer working memory, and brain structure differences in children. Chlorpyrifos is an organophosphate insecticide that inhibits an enzyme important for nerve signaling. Concerns about children focus on prenatal exposure during brain development. A 2011 study in Environmental Health Perspectives by Virginia Rauh and colleagues at Columbia University followed children in New York City whose chlorpyrifos exposure was measured in umbilical cord blood. At age seven, each standard deviation increase in prenatal exposure was associated with a 1.4 percent decline in full-scale IQ and a 2.8 percent decline in working memory, after accounting for maternal education, maternal IQ, and home environment. A 2012 follow-up in the Proceedings of the National Academy of Sciences compared brain imaging of 20 children with high prenatal exposure to 20 with low exposure and found differences in cortical surface features, including frontal and parietal thinning, with an inverse dose-response relationship.

A study published alongside it by Maryse Bouchard and colleagues in the CHAMACOS cohort of farmworker families in California’s Salinas Valley measured organophosphate metabolites in mothers’ urine during pregnancy. Children whose mothers were in the highest exposure quintile had an average 7.0-point lower IQ at age seven than those in the lowest quintile; postnatal exposure was not associated with IQ. These and other studies informed EPA’s scientific assessments of chlorpyrifos and decisions by Hawaii, California, and other states to ban it.

Is It Risky to Live Near Sprayed Fields?

Living near intensively sprayed fields can increase pesticide exposure through drift, and studies link proximity to agricultural pesticide use with higher residues and some health concerns, especially for children. Concerns in Hawaii centered on chlorpyrifos and also on drift, the movement of pesticides through air away from target fields. A 2011 study in Environmental Health Perspectives by Soo-Jeong Lee and colleagues identified 2,945 cases of acute pesticide illness associated with agricultural drift in 11 states from 1998 through 2006. Forty-seven percent were exposed at work, 92 percent experienced low-severity illness, and 14 percent were children under 15. Agricultural workers and residents of agricultural regions had the highest rates, and soil fumigations caused some of the largest incidents.

Studies have also examined longer-term associations between living near agricultural pesticide applications and children’s development. The 2014 CHARGE study in Environmental Health Perspectives by Janie Shelton and colleagues in California found that about one-third of mothers lived within 1.5 kilometers of an agricultural pesticide application during pregnancy and that proximity to organophosphates was associated with a 60 percent increased risk of autism spectrum disorder. A 2017 CHAMACOS analysis in Environmental Research by Robert Gunier and colleagues found that each tenfold increase in nearby use of the fumigants methyl bromide and chloropicrin was associated with decreases of about 2.4 to 2.6 points in children’s full-scale IQ at age seven. These observational studies cannot prove cause, but they inform the debate over buffer zones.

Where Federal Policy Stands

Federal action on chlorpyrifos has shifted several times. The EPA proposed revoking food tolerances in 2015, reversed course in 2017, and, after court orders, revoked all food tolerances in 2021. A federal appeals court vacated that decision in 2023, and the EPA subsequently moved to limit uses to a smaller set of crops. Meanwhile, the main U.S. manufacturer stopped producing chlorpyrifos in 2020, and several states banned it. In Hawaii, the state ban remains in effect regardless of federal decisions.

The Debate Continues

Advocates argue that Hawaii’s 100-foot school buffers are too small, given research showing pesticide drift can travel much farther. A 2026 Senate bill (SB2103), like similar bills in earlier sessions, proposed expanding buffer zones around schools to one-half mile and requiring more detailed public disclosure of restricted-use pesticide use by county. Agricultural groups have raised concerns about effects on farming near schools. Seed company operations in Hawaii have also contracted in recent years as companies consolidated, changing the landscape of the debate.

Restricted-Use Pesticides Explained

The EPA classifies certain pesticides as restricted-use because, without additional precautions, they could cause unreasonable harm to people or the environment. Only certified applicators, or people working under their direct supervision, may buy and apply them. Restricted-use products include some organophosphate insecticides like chlorpyrifos formulations, soil fumigants, and certain herbicides such as paraquat and atrazine. Hawaii’s Act 45 focused on restricted-use pesticides because they carry higher hazards and because their use is tracked through applicator records. Annual reporting allows the state to publish aggregated data on which restricted-use pesticides are used, in what amounts, and in which areas, information that communities had long requested.

Native Hawaiian and Community Concerns

Community groups on Kauai and Molokai, including Native Hawaiian organizations, framed pesticide use as an environmental justice issue, arguing that rural, lower-income, and Native Hawaiian communities near seed company fields bore disproportionate exposure risks. The 2019 EPA agreement with the Hawaii Department of Agriculture followed a civil rights complaint making these arguments. Concerns also extended to water quality, coral reefs, and traditional practices such as fishing and gathering, which can be affected by pesticide runoff into streams and nearshore waters. These concerns illustrate how pesticide debates involve toxicology along with land use history, culture, and equity.

Agriculture’s Changing Role in Hawaii

Hawaii’s agriculture has transformed over the past half century. Large sugar and pineapple plantations closed, leaving thousands of acres available, some of which seed companies leased. Seed production became one of the state’s most valuable agricultural sectors for a time, though its footprint has declined in recent years as companies consolidated operations. State leaders have promoted diversified agriculture and food self-sufficiency, since Hawaii imports most of its food. Debates over pesticides intersect with these goals: supporters of seed companies emphasized jobs and land stewardship, while critics argued that land should be used for food production for local residents with fewer chemical inputs.

How Do Pesticide Buffer Zones Work?

Buffer zones prohibit spraying restricted pesticides within a set distance of sensitive sites like schools during certain hours; Hawaii set a 100-foot school buffer, and later bills proposed expanding it. Buffer zones restrict pesticide applications within a set distance of sensitive areas such as schools, homes, hospitals, or waterways. Their effectiveness depends on distance, pesticide type, application method, wind, and weather. Aerial and air-blast sprayers can cause more drift than ground applications, and volatile pesticides such as fumigants can move as vapor over greater distances. Hawaii’s 100-foot school buffers apply only during school hours, which critics argue does not account for residues or volatilization after applications. Proposals for half-mile buffers reflect research on drift distances, while agricultural groups argue that larger buffers would remove substantial land from production near schools. Other states, such as California, have adopted notification requirements and restrictions on certain applications near schools.

Protecting Children From Pesticide Exposure

Parents in agricultural areas can take steps to reduce children’s exposure: keep windows closed during nearby spraying, remove shoes at the door to avoid tracking residues inside, wash children’s hands after outdoor play, wash produce before eating, and store any household pesticides securely. Families can learn about local spraying through state pesticide use reports and, where available, notification programs. Pregnant people in agricultural communities may discuss exposure concerns with their health care providers. Schools can adopt integrated pest management on their own grounds and communicate with neighboring farms about application schedules.

Organophosphates in the Diet

Beyond drift, organophosphate residues on food are a source of exposure for the general population. Before restrictions, chlorpyrifos was used on many crops, including fruits, vegetables, nuts, and grains. Studies of children switched to organic diets have shown rapid declines in urinary organophosphate metabolites, indicating diet is a major exposure source. Washing produce reduces some surface residues, and choosing organic versions of produce that typically carry higher residues can reduce exposure further. Federal restrictions on chlorpyrifos food uses, though changing over time, have reduced its presence in the food supply.

Key Facts at a Glance

Kauai County’s 2013 Bill 2491 required pesticide disclosure and buffer zones but was ruled preempted in 2014. Hawaii’s Act 45 of 2018 made it the first state to ban chlorpyrifos, with a full ban from January 1, 2023, plus 100-foot school buffer zones during school hours and annual restricted-use pesticide reporting. Ten workers were hospitalized after a 2016 chlorpyrifos exposure at a Syngenta farm on Kauai; EPA settled for a $150,000 penalty and $400,000 in training. Cohort studies linked prenatal organophosphate exposure to an average 7-point IQ deficit in the highest exposure group, and proximity to organophosphate applications to higher autism risk.

Common Myths

“Hawaii banned all pesticides near schools.” Act 45 restricts restricted-use pesticides within 100 feet of schools during school hours.

“Chlorpyrifos is banned nationwide.” Federal status has changed several times; several states, including Hawaii, ban it independently.

“Studies prove pesticides caused specific illnesses in Hawaii.” State investigations did not establish clear causal links for specific community health complaints, though research elsewhere informs concerns.

“Seed companies are the only pesticide users.” Other agriculture, landscaping, and households also use pesticides.

Key Terms

Chlorpyrifos: An organophosphate insecticide linked in studies to neurodevelopmental effects in children.

Restricted-use pesticide: A pesticide that may be applied only by certified applicators because of potential hazards.

Buffer zone: An area around sensitive sites where pesticide applications are restricted.

Drift: Movement of pesticides through air away from the target area.

Preemption: A legal doctrine under which higher-level law overrides lower-level law.

The Bottom Line

Hawaii’s pesticide debate grew from the concentration of seed company operations near communities, worker exposure incidents, and research linking organophosphate pesticides to children’s neurodevelopment. After county laws were struck down, the state enacted Act 45 in 2018, banning chlorpyrifos, requiring school buffer zones, and mandating public reporting of restricted-use pesticides. Advocates continue to push for larger buffers and more transparency, while agricultural groups raise concerns about impacts on farming. The Hawaii experience shows how local activism, research, and state policy can reshape pesticide practices even as federal decisions shift.

Further Reading

The Hawaii State Legislature website provides the text of Act 45 and later bills. The Hawaii Department of Agriculture publishes restricted-use pesticide reports. Peer-reviewed studies cited here describe chlorpyrifos and organophosphate effects on children and pesticide drift illnesses. News coverage from Kauai and Honolulu outlets documents the community debate.

Lessons for Other Communities

Communities near agricultural operations elsewhere can learn from Hawaii’s experience. Data matter: public reporting of pesticide use allows residents and researchers to understand exposure patterns. State law often determines what local governments can do, so effective policy change may require state-level action. Collaboration among farmers, residents, health professionals, and regulators can produce practical measures such as notification systems, application timing that avoids school hours, and drift-reducing equipment. Research on exposure and health effects provides an evidence base for decisions, while respectful dialogue helps manage tensions between economic and health concerns.

A Balanced View

Hawaii’s pesticide debate involved real tensions: seed companies provided jobs and kept former plantation land in agriculture, while nearby communities faced exposure risks and worker incidents occurred. Research on organophosphates and children’s neurodevelopment supported precautionary measures such as the chlorpyrifos ban and school buffers, though studies of specific Hawaii communities did not establish clear causal links for reported health complaints. Policies that combine transparency, sensible buffers, worker protection, and support for diversified agriculture can address legitimate concerns while recognizing agriculture’s role in the islands’ economy and future food security.

Worker Protection Standards

The Kauai incidents highlighted the importance of the EPA’s Agricultural Worker Protection Standard, which requires employers to notify workers of pesticide applications, enforce restricted-entry intervals after spraying, provide protective equipment, offer decontamination supplies, and arrange prompt medical transport after exposures. The standard was updated in 2015 to strengthen training, establish a minimum age for pesticide handlers, and add application exclusion zones around equipment. Farmworker advocates argue that enforcement remains uneven, especially where workers face language barriers or fear retaliation. Training required under the Syngenta settlement aimed to improve compliance across Hawaii and Pacific territories.

Workers who believe they have been exposed to pesticides can seek medical care, report incidents to state agriculture departments, and contact legal aid or worker advocacy organizations for assistance.

Looking Ahead

Hawaii’s pesticide policies continue to evolve. Lawmakers have repeatedly considered expanding buffer zones, adding notification requirements, and increasing transparency of pesticide use data. The state’s push for food self-sufficiency and diversified agriculture may shift land use away from seed production toward local food crops, which could change pesticide use patterns. Federal decisions on chlorpyrifos and other organophosphates will affect the rest of the country, while Hawaii’s ban remains in place. Monitoring pesticide use reports and health research will help residents and policymakers evaluate whether current protections are sufficient.

Residents can follow legislative sessions and public comment periods to participate in these decisions.

Public Meetings and Community Tension

Public meetings on pesticides in Hawaii were often emotional and crowded, with seed company employees, farmers, parents, physicians, and activists voicing sharply different views. Employees worried about jobs and felt their work was misrepresented, while residents described health fears and frustration with the lack of data. Some meetings ran for many hours as hundreds of people testified. These tensions strained relationships in small island communities, where neighbors and family members sometimes stood on opposite sides. The experience shows how pesticide debates can become deeply personal, and why transparent data and respectful processes matter for resolving them.

Pesticides and Hawaii’s Environment

Hawaii’s ecosystems are especially vulnerable to pollution because of steep watersheds, heavy rainfall, and nearshore coral reefs. Pesticides and sediment from agricultural land can wash into streams and coastal waters, where they may affect aquatic life and reef health. State monitoring has detected pesticides in some streams and groundwater. Native Hawaiian practitioners who fish and gather in coastal areas have raised concerns about contamination. Protecting watersheds through buffer strips, erosion control, and reduced pesticide use benefits both ecosystems and communities that depend on them.

Practical Takeaways

Residents of agricultural areas can check state pesticide use reports, sign up for notification programs where available, and contact state agriculture departments with drift complaints. Parents can ask schools about pesticide practices on and near school grounds. Workers should know their rights under the Worker Protection Standard and report unsafe practices. Policymakers can use exposure data and health research to set buffer zones and notification requirements that balance agricultural needs with community protection, and should fund agencies adequately to implement and enforce them.

What Other States Have Done

Hawaii was the first state to ban chlorpyrifos, followed by California, New York, Maryland, and others that restricted or banned its use. California, which has the most detailed pesticide use reporting system in the nation, adopted regulations requiring notification and restricting certain applications near schools and child care centers. These state actions show how states can act independently of federal decisions to address local concerns, often building on research conducted in agricultural communities such as California’s Salinas Valley.

Together, these state policies form a patchwork of protections that varies widely depending on where a family lives, which is why advocates continue to call for stronger national standards for pesticide use near schools and homes, while agricultural groups favor approaches tailored to local crops and conditions.

Families moving to or living in agricultural regions anywhere can use Hawaii’s experience as a guide, asking local officials about pesticide reporting, school buffer policies, and how drift complaints are handled, so they can make informed decisions and participate in shaping local protections.

Clear information and community involvement remain the foundation of effective pesticide policy in any setting.

Hawaii’s experience shows that sustained community engagement, combined with research and state legislation, can produce lasting changes in how pesticides are used near homes and schools.

Staying informed is the first step toward safer communities.

Frequently Asked Questions

Why was Hawaii a center of pesticide controversy?

Hawaii’s year-round growing season made it the main U.S. location for seed companies to test and produce genetically engineered crops. This concentrated heavy use of restricted-use pesticides near homes, schools, and water, prompting community concern over drift, worker exposures, and children’s health that eventually led to new state pesticide laws.

Did Hawaii ban chlorpyrifos?

Yes. Hawaii’s Act 45 of 2018 made it the first U.S. state to ban chlorpyrifos, an organophosphate insecticide linked to harm to children’s brain development, with a full prohibition taking effect on January 1, 2023. The federal EPA later took its own actions on chlorpyrifos in food uses.

What are Hawaii’s school pesticide buffer zones?

Under Act 45, restricted-use pesticides cannot be applied within 100 feet of schools during school hours, and large agricultural users must report their applications. Bills introduced in 2025 and 2026 proposed expanding these buffers to as much as half a mile, reflecting ongoing concern about pesticide drift near children.

What does research show about chlorpyrifos and children?

Multiple cohort studies have linked higher prenatal exposure to chlorpyrifos with lower IQ, poorer working memory and attention, and measurable differences in brain structure in children. These findings contributed to decisions by Hawaii and later the EPA to restrict the pesticide’s use, particularly around schools and on food crops.

What happened to Kauai’s Bill 2491?

Kauai County passed Bill 2491 in 2013 to require buffer zones and disclosure of pesticide and GMO use, but a federal court ruled in 2014 that state law preempted the county ordinance, a decision upheld on appeal. The fight helped drive the later statewide law, Act 45, in 2018.

How can people reduce pesticide exposure near farms?

Residents near agricultural areas can learn local spraying schedules, keep windows closed during applications, wash produce and remove shoes indoors to limit tracked-in residues, and support buffer zones and disclosure rules. Families with young children or pregnant members may take extra precautions, since children are most sensitive to pesticide exposure.

References

1. Rauh V, Arunajadai S, Horton M, et al. Seven-year neurodevelopmental scores and prenatal exposure to chlorpyrifos, a common agricultural pesticide. Environmental Health Perspectives. 2011;119(8):1196–1201. PMID 21507777
2. Rauh VA, Perera FP, Horton MK, et al. Brain anomalies in children exposed prenatally to a common organophosphate pesticide. Proceedings of the National Academy of Sciences. 2012;109(20):7871–7876. PMID 22547821
3. Bouchard MF, Chevrier J, Harley KG, et al. Prenatal exposure to organophosphate pesticides and IQ in 7-year-old children. Environmental Health Perspectives. 2011;119(8):1189–1195. PMID 21507776
4. The Garden Island. EPA will not ban chlorpyrifos; Hawaii’s Act 45 ban stands. thegardenisland.com
5. Honolulu Star-Advertiser. Voluntary pesticide disclosure takes effect on Kauai. staradvertiser.com
6. West Hawaii Today. EPA and HDOA reach resolution on pesticide regulation. 2019. westhawaiitoday.com
7. Honolulu Civil Beat. EPA settles Syngenta pesticide claim. February 2018. civilbeat.org
8. Hawaii Tribune-Herald. Seed company, EPA settle on pesticide violations. hawaiitribune-herald.com
9. Hawaii State Legislature. SB2103 SD2, Relating to Pesticides (2026). capitol.hawaii.gov
10. Lee SJ, Mehler L, Beckman J, et al. Acute pesticide illnesses associated with off-target pesticide drift from agricultural applications: 11 States, 1998–2006. Environmental Health Perspectives. 2011;119(8):1162–1169. PMID 21642048
11. Shelton JF, Geraghty EM, Tancredi DJ, et al. Neurodevelopmental disorders and prenatal residential proximity to agricultural pesticides: the CHARGE study. Environmental Health Perspectives. 2014;122(10):1103–1109. PMID 24954055
12. Gunier RB, Bradman A, Castorina R, et al. Residential proximity to agricultural fumigant use and IQ, attention and hyperactivity in 7-year old children. Environmental Research. 2017;158:358–365. PMID 28686950

Last updated: October 6, 2026