Pest Control Caused 9 of 210 School Pesticide Illnesses
Key result: California investigated 210 pesticide illness cases at schools from 2016 to 2023. Disinfectants and cleaners caused 75, applications on nearby farms 49, and swimming pool chemicals 40. Pest control services treating school buildings caused 9 cases in three incidents, 4.3 percent of the total.
What counts as a school case
California’s Pesticide Illness Surveillance Program investigates reported illnesses that may be linked to pesticides and publishes each case, with a narrative, through the California Pesticide Illness Query (CalPIQ). Disinfectants, sanitizers and pool chlorine are regulated as pesticides, so they are in the record. We downloaded every case where the incident setting was a school, 2016 to 2023, and assigned each to a source using the pesticide, application site and investigator’s narrative.
The setting includes colleges and universities as well as K-12 schools: 8 of the narratives describe a university or college. Cases are counted by person; one incident can produce many cases. The 210 cases came from 122 separate incidents.
Sources of exposure
| Source | Cases | Incidents | Example from the narratives |
|---|---|---|---|
| Disinfectants and cleaners | 75 | 75 | Bleach splashed in a custodian’s eye while rinsing a rag |
| Farm applications nearby | 49 | 7 | Herbicide applied to an almond orchard next to a school during a fire drill |
| Swimming pool chemicals | 40 | 13 | Chlorine gas pushed into a university pool; 21 swimmers exposed |
| Weed control on school grounds | 18 | 11 | Herbicide applied during school hours, suspended only for recess |
| Other or unknown | 11 | 11 | Insect repellent sprayed in a student’s eye |
| Pest control service at the school | 9 | 3 | Classrooms treated for fleas and spiders; seven people ill on return |
| Neighbouring home use | 8 | 2 | Homeowner’s perimeter spray 300 feet from a school |
| Total | 210 | 122 |
Source: California Department of Pesticide Regulation, CalPIQ, incident setting School, cases identified 2016 to 2023, retrieved 5 October 2026. Sources assigned by the author; incidents grouped by the department’s episode numbers. Every case, with its narrative, is in the CSV.
What it means. Cleaning and pool chemicals together made 115 of the 210 cases, 54.8 percent. Every disinfectant case was a separate one-person incident, and 48 of the 75 narratives involve custodians, janitors, kitchen or cafeteria staff, or maintenance workers. Pest control services were among the smallest sources.
What limits it. The record holds reported and investigated cases only. Mild illnesses, and those not linked to a pesticide by a doctor, are missing. Relationship ratings vary: 43 cases were rated definite, 143 probable and 24 possible.
The three pest control incidents
- 2016, Los Angeles County. In the department’s narrative, a structural pest control operator “fogged an instrument storeroom” and sprayed carpets without aerating the areas afterwards; a teenager who collected an instrument the next day developed rashes.
- 2017, Orange County. Three classrooms were treated for fleas and spiders. When classes resumed three days later, three teachers and four students from the treated rooms had symptoms. Two teachers told investigators they saw no postings or warnings.
- 2020, Riverside County. A school employee felt symptoms on returning to her office after winter break; school records showed an insecticide application 20 days earlier.
Two other cases involved pest control products without a pest control service: a student who ingested cockroach gel bait, and a groundskeeper who inhaled food-grade diatomaceous earth a teacher had put down for ants. Separately, in 2020 a homeowner’s insecticide spray around a house about 300 feet from a San Diego County school was linked to seven cases among the principal and staff.
California’s Healthy Schools Act requires schools to notify staff and parents each year of the pesticide products expected to be used, and to give at least 72 hours’ notice of individual applications to those who register for it.
Farm applications next door
All 49 farm-related cases were in 2021 to 2023, in seven incidents. 38 involved almond orchards, 8 broccoli and 3 grapes. The largest, in Stanislaus County in 2023, began during a fire drill: herbicides were being applied to an almond orchard next to the school, with what the narrative calls “a 25-foot allowable buffer” from the orchard’s edge to the school fence, when the wind picked up toward the school. A school official told investigators that 19 students, three teachers and two parents developed symptoms; 22 cases were recorded.
Since 1 January 2018, state regulation has set minimum distances between schoolsites and some farm applications: a quarter mile for aircraft, airblast sprayers, sprinkler chemigation, dusts and fumigants, and 25 feet for ground-rig sprayers.
Year by year
What it means. Annual counts swing with single large incidents: the 2018 peak includes 21 swimmers from one pool, and the 2023 total includes 22 cases from the Stanislaus orchard incident.
Checks
1. Complete download
Result. 210 case rows, one per case number per year, with no duplicates.
2. Pest control cases
Method. Every narrative was searched for structural pest control operator (SPCO), pest control, exterminator and pest names, and every match was read.
Download the data
The tables in this report are published as CSV files under a Creative Commons Attribution 4.0 licence. You may republish, remix and build on them, including commercially, with attribution to The Pest Control Brief and a link to this page.
- All 210 pesticide illness cases at California schools, 2016 to 2023, with source, incident and narrative (CSV, 210 rows)
How to cite this report
The Pest Control Brief, “Pest Control Services Caused 9 of 210 Pesticide Illness Cases at California Schools in Eight Years. Disinfectants, Pools and Farm Drift Caused Most”, 2 October 2026. https://thepestcontrolbrief.com/school-pesticide-exposure-data/
References
- California Department of Pesticide Regulation. California Pesticide Illness Query (CalPIQ), detail export, incident setting School, 2016 to 2023. apps.cdpr.ca.gov/calpiq. Retrieved 5 October 2026.
- California Education Code section 17612 (Healthy Schools Act notification). leginfo.legislature.ca.gov EDC 17612. Accessed 5 October 2026.
- California Code of Regulations, title 3, section 6691, Pesticide Application Restrictions (schoolsites), operative 1 January 2018. law.cornell.edu 3 CCR 6691. Accessed 5 October 2026.
Method
Data. CalPIQ case detail for incident setting School, all pesticide types, agricultural and non-agricultural, years 2016 to 2023.
Sources. Agricultural cases are those the department classes as agricultural; pool cases those with a pool application site; others assigned from the pesticide and narrative.
Limitations. Reported cases only; schools include higher education; source assignment is the author’s and is shown for every case in the CSV.
Last reviewed: 5 October 2026.
For education reporters
Most quotable statistics
- California investigated 210 pesticide illness cases at schools from 2016 to 2023.
- Disinfectants and cleaners caused 75 and swimming pool chemicals 40.
- Applications on nearby farms caused 49 cases, all from 2021 to 2023.
- Pest control services treating school buildings caused 9 cases in three incidents.
Press summary
Pesticide illnesses at California schools come mostly from cleaning chemicals, pool chlorine and farms next door, not pest control, according to an analysis of state illness records by The Pest Control Brief. Of 210 cases from 2016 to 2023, disinfectants and cleaners caused 75, nearby farm applications 49 and pool chemicals 40. Pest control services treating school buildings caused 9 cases in three incidents over eight years.
Headlines editors could use
- The pesticides making people sick at school are mostly cleaners
- Farm drift sent 49 school cases to investigators in three years
- Pest control caused 9 of 210 school pesticide illnesses
Common questions
Is pest control at schools dangerous?
Reported illnesses are rare: 9 cases in three incidents at California schools from 2016 to 2023 were linked to pest control services treating school buildings.
What causes most pesticide illnesses at schools?
Disinfectants and cleaners, which are regulated as pesticides: 75 of 210 cases. Pool chemicals caused 40.
Does farm pesticide drift reach schools?
Yes. 49 cases at schools from 2021 to 2023 were linked to farm applications nearby, 38 of them involving almond orchards.
Do schools have to tell parents about pesticide use?
In California, yes: an annual notice of products expected to be used, and at least 72 hours’ notice of individual applications for those who register.
Where can I read the cases?
All 210, with investigators’ narratives, are in the CSV above.
