Paraquat Exposure: Who Was Exposed and How
A clear breakdown of occupational, drift, and residential paraquat exposure — and the documentation that supports each type.
Occupational exposure
Most paraquat Parkinson's claimants were exposed at work, over multiple years, through repeated low-level contact during routine agricultural activities. The principal occupational exposure categories:
Mixers and loaders
Mixers and loaders work with paraquat in its most concentrated form. Paraquat is sold as a concentrate that must be diluted with water before application. Mixing and loading produce inhalation and dermal exposure to high-concentration product. Splashes, drips, and accidental skin contact are common; many older mixing operations were performed without modern PPE.
Applicators (ground)
Ground applicators — operating tractor-mounted sprayers, hand-held sprayers, or backpack sprayers — are exposed to paraquat mist throughout the work day. Wind shifts, clogged nozzles, and spray drift onto the operator are routine. Cabbed tractors with modern filtration help, but most historical applications used open cabs or no cab at all.
Crop-dusting pilots and aerial applicators
Aerial applicators experience cockpit contamination during loading, in-flight venting, and post-flight cleanup. Pilots, loaders, and ground support crews all have documented elevated exposure profiles.
Equipment cleanup and maintenance
Tank rinsing, hose flushing, nozzle servicing, and end-of-day decontamination produce repeated low-level dermal exposure to concentrated residues. Maintenance workers who never personally applied paraquat are often exposed comparably to applicators.
Re-entry workers
Field workers who re-enter treated fields before the labeled re-entry interval expires — for irrigation, scouting, or hand weeding — have measurable elevated exposure. EPA re-entry intervals have tightened over time; historical re-entry was often premature.
Documentation for occupational exposure
- Employer payroll records and W-2s showing dates of agricultural employment
- Applicator license records (state agriculture department)
- Pesticide use reports filed with state agencies
- Supplier invoices showing paraquat purchases
- Co-worker affidavits and witness statements
- Photographs of work activities and equipment
- OSHA records and worker compensation files
- Personal calendars, diaries, and crop journals
Environmental drift exposure
Paraquat drift from ground or aerial application has been documented in residences and outdoor work areas within drift distance of treated fields. Drift exposure typically does not reach occupational levels, but cumulative drift over many growing seasons can support a claim — particularly when proximity is consistent and application records establish heavy paraquat use on adjacent fields.
Residential proximity exposure
People who lived near agricultural fields where paraquat was applied may have residential proximity exposure. Documentation is harder than for occupational claims but not impossible — county agricultural records, neighbor affidavits, USGS pesticide use maps, and aerial photography from the exposure period can all contribute. Residential drift cases generally need stronger differential diagnosis to be viable.
Reconstructing exposure when records are gone
Most paraquat plaintiffs were exposed 20 to 40 years before diagnosis. Direct documentation from that long ago is often incomplete. Your legal team will work to reconstruct exposure through:
- State agriculture department applicator licensing archives
- Successor company records for defunct employers
- Federal and state pesticide use reporting databases
- Co-worker depositions and contemporaneous witnesses
- Expert reconstruction by industrial hygienists
Do not let missing records stop you from calling. Most cases get built from partial records, witness testimony, and expert reconstruction.
What exposure looks like in court
Defendants commonly challenge exposure on three grounds: dose (was it enough to plausibly cause injury?), duration (was the exposure cumulative or one-time?), and confounders (other pesticide or environmental exposures). Strong cases anticipate all three. The best documentation establishes regular contact over multiple growing seasons.
See also: Paraquat & Parkinson's, Do I Qualify?, Evidence and Documentation →