Restricted Use Pesticide Usage: Upcountry Maui

Makawao, pukaLani, and Kula

Executive Summary (2020 - 2021)

This brief examines reported Restricted Use Pesticide (RUP) applications in Upcounty Maui including Makawao, Pukalani & Kula for 2020–2021. Data show extensive use of highly hazardous chemicals, including fumigants, organophosphates, carbamates, synthetic pyrethroids, and persistent herbicides. These chemicals pose serious risks to human health, particularly children, and to the environment. 

It is important to note the GIS mapping for 2020 and 2021 below is likely inaccurate and underestimated. Incomplete/poor pesticide use data reporting for 2020 and 2021, including the application of fumigants (Telone) that likely occurred in Makawao in 2021 could not be mapped.

2020 & 2021

Key Findings

• Fumigants dominate use, with Telone II (1,3-Dichloropropene) and Dormex applied in large quantities, posing drift, inhalation, and groundwater contamination risks.

• Neurotoxic insecticides (diazinon, methomyl, oxamyl, naled) were applied repeatedly.

• Synthetic pyrethroids and persistent herbicides threaten pollinators, aquatic life, and water quality.

• Chemical mixtures are standard, creating compounded health and ecological risks not fully assessed under current regulations.

• Inaccuracies in the data reporting prevented 117lbs of active ingredient, across five Maui parcels, from being able to be mapped. Based on known use patterns, one parcel is likely Haliʻimaile Pineapple Company, the island’s only known prior Telone user.

2020 Findings

• Telone II (1,3-Dichloropropene) — 20,354 lbs AI; volatile, probable human carcinogen

• Dormex (Hydrogen Cyanamide) — 143 lbs AI; highly reactive, drift and respiratory hazard

• Methomyl — 173.7 lbs AI; acute neurotoxin

• Diazinon — 350 lbs AI; developmental neurotoxicity risk

• Paraquat — 31.4 lbs AI; extreme acute toxicity, no antidote

• Pyrethroids — Permethrin, Lambda- and Zeta-cypermethrin, Esfenvalerate, Bifenthrin; high aquatic toxicity

• S-metolachlor & Tolfenpyrad — persistent herbicides with groundwater mobility

Observation: Multiple RUPs applied in the same areas, elevating cumulative exposure risk near schools and homes.

2021 Findings

• Telone II (1,3-D) — 18,657 lbs AI; consistent high exposure risk

• Dormex — 379.5 lbs AI; significant increase

• Methomyl & Oxamyl — 166.6 lbs AI / 15.84 lbs AI

• Cyantraniliprole / Chlorantraniliprole — 12.12 / 4.89 lbs AI

• Pyrethroids — multiple compounds, including Permethrin, Lambda- and Zeta-cypermethrin, Bifenthrin, Esfenvalerate

• Paraquat — 34.2 lbs AI

• S-metolachlor — 13.97 lbs AI

• Naled — 113.2 lbs AI

Observation: Toxic chemical load increased slightly from 2020; cumulative risk remains high, with repeated overlapping applications.

Human Health Concerns

• Children at greatest risk, especially in schools near pesticide applications (Makawao Elementary, Kula Elementary, King Kekaulike High, Pukalani Elementary)

• Neurodevelopmental harm – organophosphates, carbamates

• Acute poisoning – cholinesterase inhibition from carbamates and organophosphates; respiratory distress

• Endocrine and immune disruption – pyrethroids and chlorinated compounds

• Chronic disease risk – Parkinson’s, cancer, reproductive harm

• Exposure pathways: inhalation, dust/soil contact, contaminated water, drift

Environmental Concerns

• Aquatic toxicity – pyrethroids, abamectin, emamectin, naled, bifenthrin

• Pollinator decline – chlorantraniliprole, cyantraniliprole, pyrethroids

• Groundwater contamination – S-metolachlor, Telone II, methomyl

• Soil and ecosystem disruption – microbial community loss, reduced habitat quality

• Cumulative ecological stress – repeated overlapping pesticide applications amplify long-term environmental harm

Why Mixture Effects Matter

• Overlapping applications of fumigants, insecticides, herbicides, and pyrethroids increase human and ecological risks.

• Combined exposures can cause: neurodevelopmental harm, endocrine disruption, chronic disease, immune impacts, and long-term ecological damage.

• Regulatory frameworks rarely assess cumulative or synergistic exposure, leaving children and communities particularly vulnerable.

Schools at Risk

There are nine schools in this region within one mile of RUP applications (2020-2021).

1. Haleakala Waldorf School, Kula

2. Horizons Academy of Maui, Inc., Kihei

3. Montessori School of Maui, Makawao

4. Kalama Intermediate, Makawao

5. Kula Elementary, Kula

6. Makawao Elementary, Makawao

7. Pukalani Elementary, Pukalani

8. Waihee Elementary, Waihee

9. Wailuku Elementary, Wailuku

Overall Conclusion

Pesticide use in Makawao, Kula & Upcountry is intensive, repetitive, and highly toxic, with significant implications for child health, community well-being, water quality, and ecosystem integrity. Findings underscore the need for:

1. Buffer zones around schools, homes, and water catchments

2. Stronger reporting and transparency of pesticide use

3. Cumulative and mixture-based risk assessment

4. Enhanced regulatory oversight and enforcement

Protective policies are urgently needed to reduce exposure to hazardous pesticides in frontline communities.

If you want the full Upcountry Maui Report, email safefarmssafefood@gmail.com