Lorsban Parkinson’s Disease Lawsuit Overview

Lorsban lawsuits are being investigated for farmers, pesticide applicators and other agricultural workers who developed Parkinson’s disease after years of handling or working around the chlorpyrifos-based insecticide.

For decades, Lorsban was widely applied to field crops, orchards, vegetables and other plants through foliar sprays, soil treatments and irrigation systems. The EPA estimated that approximately 10 million pounds of chlorpyrifos were used annually in agriculture by 2002, including about 5.5 million pounds on corn, and an average of 5.1 million pounds was still applied each year between 2014 and 2018.

Pesticide exposure may have occurred while transporting containers, measuring concentrate, filling tanks, operating sprayers, loading aircraft, maintaining irrigation systems, repairing contaminated equipment or returning to treated fields. People who lived or worked near farms and orchards may also have experienced repeated exposure through pesticide drift.

Research has linked chlorpyrifos exposure to an increased risk of developing Parkinson’s disease, including research published in Molecular Neurodegeneration and highlighted by UCLA Health in January 2026.

Chlorpyrifos Parkinson’s disease lawsuits now allege manufacturers failed to adequately investigate or warn that repeated exposure could cause permanent neurological damage, Parkinson’s disease and other neurological health concerns years or decades later.

Lorsban Exposure and Parkinson’s Disease

A 2025 study published in Molecular Neurodegeneration examined whether exposure to chlorpyrifos was associated with Parkinson’s disease and whether the connection was biologically plausible.

Researchers analyzed residential and workplace exposure among 829 individuals with Parkinson’s disease and 824 control subjects. They also studied the effects of chlorpyrifos in laboratory models to determine whether the pesticide produced neurological changes consistent with the disease.

UCLA Health reported in January 2026 that participants with long-term residential chlorpyrifos exposure had more than a 2.5-fold increased risk of Parkinson’s disease. The laboratory research also identified dopamine-neuron loss, movement problems, brain inflammation and alpha-synuclein accumulation following exposure.

Chlorpyrifos is an organophosphate pesticide that blocks acetylcholinesterase, an enzyme required for normal communication between nerves and muscles. This causes the nervous system of an insect to become overstimulated, leading to paralysis and death.

The Parkinson’s disease concerns extend beyond this immediate mechanism. Research has identified neurological changes involving:

• Oxidative stress
• Mitochondrial dysfunction
• Inflammation in the brain
• Damage to dopamine-producing neurons
• Accumulation of alpha-synuclein
• Disruption of cellular waste-removal processes

Parkinson’s disease develops as the brain cells responsible for producing dopamine gradually become damaged or die, disrupting the brain’s ability to control smooth, coordinated movement. Because this damage may progress slowly over many years, a farmer or pesticide applicator could stop working with Lorsban long before noticing tremors, muscle stiffness, slowed movement or balance problems.

Potential Lorsban Parkinson’s Disease Symptoms

Parkinson’s disease is a progressive neurological disorder that affects movement and may also cause cognitive, emotional, digestive and movement disorders.

The early stages of the disease can be subtle. A person may notice that one hand shakes slightly, one arm no longer swings normally while walking or familiar tasks take more time. Family members may also notice changes in posture, speech, facial expression or handwriting.

Motor Symptoms

Motor symptoms affect movement, balance and muscle control and may include:

• Tremors
• Muscle stiffness
• Slowed movement
• Balance and coordination problems
• Shuffling steps or difficulty walking
• Reduced arm movement while walking
• Changes in posture
• Smaller handwriting
• Speech problems
• Difficulty chewing or swallowing

Non-Motor Symptoms

Parkinson’s disease may also cause symptoms unrelated to movement, including:

• Sleep disorders
• Depression and anxiety
• Memory problems
• Cognitive decline
• Fatigue
• Loss of smell
• Constipation and other digestive problems
• Urinary problems
• Dizziness when standing
• Changes in mood, motivation or concentration

There is no cure for Parkinson’s disease. Treatment may involve medications, physical therapy, occupational therapy, speech therapy and, for certain patients, procedures such as deep brain stimulation.

History and Agricultural Use of Lorsban

Chlorpyrifos was first registered for pesticide use in the United States in 1965. Dow Chemical subsequently marketed the active ingredient under several brand names, including Lorsban for agricultural pest control and Dursban for many residential and structural applications.

Lorsban was later manufactured through Dow AgroSciences and ultimately became part of Corteva Agriscience following corporate changes involving Dow and DuPont.

Over several decades, Lorsban became one of the best-known agricultural chlorpyrifos brands in the United States. It was offered in liquid, granular and powder formulations designed to control insects affecting field crops, orchards, groves, vegetables, nurseries and other commercial growing operations.

One of the most recognizable versions was Lorsban-4E. The concentrated liquid contained 44.9% chlorpyrifos, equal to four pounds of the active ingredient per gallon, and was diluted before application.

Corteva announced in 2020 that it would stop manufacturing chlorpyrifos products, including Lorsban, by the end of that year. The decision ended new Corteva production but did not itself prohibit the lawful use of existing stocks that remained in distribution or possession.

Where Was Lorsban Sold?

Lorsban was generally sold through professional agricultural suppliers rather than ordinary consumer lawn-and-garden stores. Farms and commercial applicators may have obtained the pesticide from:

• Agricultural cooperatives
• Crop-protection dealers
• Seed and fertilizer suppliers
• Regional farm-service businesses
• Wholesale agricultural chemical distributors
• Custom pesticide application companies
• Commercial fertilizer-blending operations

The farmer was not always the person who purchased the product. Agricultural cooperatives and custom applicators often selected the pesticide, delivered it to the farm, prepared the mixture and applied it using company equipment. As a result, farmworkers may have handled or worked around Lorsban regularly without knowing where it was purchased or seeing an invoice.

Lorsban was distributed in small containers, larger nonrefillable containers and refillable commercial containers. Certain agricultural businesses could also blend Lorsban-4E with dry bulk fertilizer for approved orchard-floor applications, creating additional exposure opportunities for employees who mixed, loaded, transported or applied those products.

Someone investigating Lorsban exposure from decades ago may remember the cooperative that supplied the farm, the contractor that performed the spraying, the crops treated or the containers stored in a barn or chemical building. Those details may help identify supplier records, pesticide application logs or witnesses familiar with the operation.

Lorsban Crops and Agricultural Uses

Lorsban was used to kill insects that damaged crop roots, stalks, leaves, fruit and nuts.

Its application varied by crop. In cornfields, the pesticide could be incorporated into soil before planting, placed near crop rows or sprayed after plants emerged. Orchard workers could direct it toward trunks, spray it over foliage or treat the ground beneath trees. Vegetable applications sometimes involved treating seed rows or the base of transplanted plants.

Historical Lorsban labels included uses involving:

• Corn, soybeans, cotton, wheat and alfalfa
• Apples, peaches, pears, cherries and citrus
• Almonds, walnuts, pecans and other tree nuts
• Strawberries, grapes, cranberries and figs
• Broccoli, cabbage, cauliflower and onions
• Sugar beets, sorghum, tobacco and peanuts
• Christmas tree plantations and commercial nurseries

The pesticide was commonly used against armyworms, cutworms, corn rootworms, aphids, beetles, borers, maggots, mites, scale insects, thrips, grubs, wireworms and weevils.

Lorsban Products Our Firm Is Investigating

Saiontz & Kirk is investigating Parkinson’s disease claims involving several Lorsban formulations used for different crops, pests and agricultural application methods. Although the products varied in form and concentration, each contained chlorpyrifos and may have exposed workers while mixing, loading, applying or cleaning contaminated equipment.

• Lorsban-4E: A concentrated liquid formulation containing four pounds of chlorpyrifos per gallon. Workers typically diluted the pesticide before application, creating opportunities for substantial exposure while opening containers, measuring concentrate, filling spray tanks or handling leaking hoses and transfer equipment.
• Lorsban 15G: A granular pesticide commonly applied to soil or placed along crop rows. Workers may have inhaled pesticide dust or experienced skin contact while opening bags, filling equipment hoppers, calibrating applicators and removing residue from contaminated machinery.
• Lorsban 50W: A wettable-powder formulation mixed with water before spraying. Although some versions came in water-soluble packets intended to limit direct contact, exposure could still occur when packets broke, powder became airborne or residue remained inside tanks and application equipment.
• Lorsban 75WG: Consisted of water-dispersible granules added directly to spray tanks. Workers may have encountered chlorpyrifos particles while measuring or pouring the product, preparing spray mixtures and cleaning equipment after application.
• Lorsban Advanced: A liquid formulation developed for commercial agricultural use. Farmworkers and employees of agricultural cooperatives, pesticide dealers and custom application companies may have been exposed while transferring the pesticide between storage tanks, refillable containers and spraying equipment.

How Workers Were Exposed to Lorsban

Lorsban exposure could occur throughout an agricultural application, beginning when the pesticide was delivered and continuing through mixing, spraying, equipment cleanup and entry into treated fields.

Chlorpyrifos could enter the body when a worker inhaled spray or dust, absorbed the chemical through the skin or transferred residue from contaminated hands and clothing to the face or mouth.

Mixing and Loading Lorsban

Some of the greatest exposures may have occurred while workers handled concentrated Lorsban before it was diluted. To prepare Lorsban-4E, workers generally added water to a spray tank, measured and poured the concentrate into the tank and then added the remaining water or approved carrier. The label instructed workers to maintain agitation while mixing and throughout the application.

Workers could be exposed through spills, splashes, leaking pumps, broken hoses and pesticide released while opening containers. The concentrate could saturate clothing or remain on gloves, tools and mixing equipment. Aerial applications required ground crews to repeat this process whenever a plane or helicopter returned to be refilled, potentially creating numerous contact points during a single day.

Ground, Orchard and Aerial Applications

Lorsban was applied with equipment selected for the crop and size of the property. Tractor-mounted boom sprayers were used to cover field crops. Directed nozzles could place the pesticide near plant roots or onto soil, while other equipment incorporated it into the ground before or after planting.

Orchard airblast sprayers used powerful airflow to carry pesticide into dense tree canopies. Although this improved coverage, mist could move through or above the trees and return toward the operator. Fixed-wing aircraft and helicopters were also used to treat larger areas. Pilots, loaders, mechanics and other ground personnel could all encounter Lorsban during aerial applications.

Smaller or targeted treatments could involve backpack or handgun sprayers. The 2002 Lorsban-4E label, for example, included instructions for using a backpack sprayer on certain transplanted citrus trees in Texas.

Chemigation and Equipment Cleanup

Lorsban could also be distributed through sprinkler-irrigation systems in a process known as chemigation. Workers mixed the pesticide in a holding tank and used a pump to inject it into moving irrigation water. The system had to be calibrated, monitored and adjusted so the pesticide was distributed uniformly across the intended acreage.

Historical labels authorized chemigation through systems that included center pivots, lateral-move equipment, wheel lines, travelers, big guns and certain hand-move sprinklers. Exposure could occur while preparing the mixture, checking the injection equipment, repairing leaks or flushing tanks, pumps and irrigation lines after the application.

Cleaning and maintenance also created risks outside chemigation. Mechanics could open pumps, filters and hoses containing pesticide residue, while cleanup crews handled contaminated rinsate and washed spray tanks and tractors.

Field Reentry, Spray Drift and Take-Home Exposure

Workers who did not mix or apply Lorsban may still have encountered residue in treated agricultural areas. Farm laborers could touch contaminated foliage, soil, irrigation equipment and harvested crops. Exposure risks may have been greater when workers entered an area before the pesticide residue had dissipated or without appropriate protective equipment.

Lorsban could also move away from the intended treatment area through spray drift. Wind, temperature, humidity, droplet size, nozzle position and application height all affected how far pesticide droplets traveled.

The 2012 label instructed applicators not to allow Lorsban drift to contact people, homes, farmworker housing, schools, daycare centers, nursing homes, hospitals, parks or other sensitive locations. It also established different buffer zones based on the equipment and application rate. People who lived or worked near frequently treated farms and orchards may therefore have experienced repeated exposure even if they did not take part in an application.

Agricultural workers could also carry Lorsban residue home on clothing, boots, gloves, tools and vehicles. Family members may have encountered the pesticide while handling work clothes or coming into contact with contaminated items.

Lorsban Regulatory History and Product Changes

Lorsban remained on the agricultural market for decades, but the crops it could be used on, the people permitted to handle it and the protections required during application changed substantially over time.

• 1965 — Chlorpyrifos was first registered in the United States. The pesticide was later marketed under the Lorsban name for agricultural uses involving field crops, orchards, fruit, nuts and vegetables. EPA chlorpyrifos regulatory history
• June 2000 — EPA and chlorpyrifos manufacturers agreed to eliminate most residential uses and restrict agricultural applications. The agreement halted production for nearly all homeowner uses, phased out termiticide applications in completed homes and imposed changes intended to reduce risks to children, workers and consumers. Agricultural changes included ending use on tomatoes, limiting certain apple and grape applications and revising worker reentry requirements. Although these actions were directed largely at residential products, they marked a major turning point in the regulation of chlorpyrifos brands such as Lorsban. EPA announcement of the 2000 chlorpyrifos agreement
• 2002 — Lorsban-4E remained broadly registered for agricultural use, but carried substantial handling requirements. The label classified the product as a restricted-use pesticide and warned that it could be fatal if swallowed and harmful if absorbed through the skin. Applicators and handlers were directed to use protective clothing, chemical-resistant gloves, footwear, eyewear and aprons during mixing, loading and equipment cleaning. The label also imposed restricted-entry periods before workers could return to treated fields. EPA’s 2002 chlorpyrifos reregistration fact sheet
• 2012 — EPA imposed new spray-drift controls and reduced certain application rates. The agency concluded that chlorpyrifos spray drift could create risks near treated fields and required no-spray buffer zones around homes, schools, recreational areas and other sensitive locations. EPA also lowered aerial application rates and required drift-reduction measures for ground booms, orchard airblast sprayers and aircraft. EPA chlorpyrifos regulatory timeline and 2012 spray-drift decision

Changes Reflected in the 2012 Lorsban Label

The revised Lorsban-4E label translated those broader regulatory concerns into specific requirements for agricultural operations.

Mixers and loaders supporting aerial applications had to use mechanical-transfer systems. Pilots were required to operate from enclosed cockpits, and farms could no longer use people standing in fields as human flaggers to guide aircraft. Applicators also had to observe buffer zones and take steps to prevent spray from reaching homes, farmworker housing, schools, daycare centers, hospitals and other occupied areas. EPA-approved 2012 Lorsban-4E label

The label also required many mixers, loaders and handlers to wear respirators, chemical-resistant gloves, aprons, footwear, headgear and coveralls. Clothing drenched with concentrated Lorsban was to be discarded rather than washed and reused.

These changes did not remove Lorsban from agricultural use. However, they show that the conditions surrounding its use became more restrictive as regulators addressed occupational exposure and off-target pesticide drift.

• 2020 — Corteva announced it would stop manufacturing Lorsban and other chlorpyrifos products. Corteva stated that it would end production by the close of 2020. The decision stopped new manufacturing by the company but did not immediately remove Lorsban already held by farms, cooperatives, distributors or commercial applicators.
• August 2021 — EPA revoked all chlorpyrifos food tolerances. Food tolerances establish the amount of pesticide residue legally permitted on food. By revoking all chlorpyrifos tolerances, EPA effectively stopped use of the pesticide on food and animal-feed crops. The agency said the action was intended to protect children, farmworkers and other exposed populations. EPA final action revoking chlorpyrifos food tolerances
• February 2022 — The food-use prohibition took effect. Once the tolerance revocations became effective, chlorpyrifos generally could no longer be legally applied to food or feed crops covered by the rule. Previously labeled nonfood uses were not automatically eliminated by the tolerance action. EPA update on chlorpyrifos use on food
• November 2023 — A federal appeals court vacated EPA’s 2021 tolerance rule. The U.S. Court of Appeals for the Eighth Circuit found that EPA should have considered whether some chlorpyrifos uses could safely remain rather than revoking every food tolerance. The decision required the agency to restore the earlier tolerances while it reconsidered the issue. EPA frequently asked questions on the court decision
• December 2023 and February 2024 — Chlorpyrifos food tolerances were formally reinstated. The court mandate took effect in December 2023, and EPA amended the federal regulations in February 2024 to reflect the reinstatement. This did not automatically restore canceled product registrations or revive discontinued Lorsban production. EPA update on reinstated chlorpyrifos tolerances
• December 2024 — EPA proposed retaining only 11 specified food and feed uses. EPA proposed revoking chlorpyrifos tolerances for most crops while preserving tolerances connected to limited uses on alfalfa, apples, asparagus, tart cherries, citrus, cotton, peaches, soybeans, strawberries, sugar beets and wheat. The proposal did not mean that every chlorpyrifos product could immediately be used on those crops; applicators still had to follow existing product registrations, labels and cancellation orders. EPA proposed chlorpyrifos tolerance rule
• 2025 and 2026 — EPA continued issuing cancellation orders and existing-stock instructions. Those actions addressed whether particular registered products could continue to be sold, distributed or used after their registrations or specific uses were canceled. EPA has emphasized that restored food tolerances do not override product-specific cancellation orders or permit uses that no longer appear on an approved label. EPA chlorpyrifos regulatory status page

The regulatory timeline does not establish that every Lorsban application caused Parkinson’s disease. It does show that chlorpyrifos remained under continuing review as regulators imposed stronger worker protections, drift restrictions, crop limitations and eventually broad food-use restrictions.

Lorsban Lawsuit Allegations

Lorsban lawsuits allege that the companies responsible for the pesticide failed to adequately investigate and disclose the long-term neurological risks associated with chlorpyrifos exposure.

The claims may allege that Dow, Corteva and other responsible companies:

• Failed to adequately study the effects of repeated exposure
• Failed to investigate the risk of Parkinson’s disease
• Sold an unreasonably dangerous pesticide
• Failed to warn about permanent neurological injuries
• Minimized or concealed evidence of neurotoxicity
• Relied on inadequate or misleading safety studies
• Marketed Lorsban without sufficient long-term warnings
• Continued selling the product despite evidence of neurological risks

Historical Lorsban labels warned that the pesticide could be fatal if swallowed, harmful if absorbed through the skin and capable of causing acute organophosphate poisoning. They also instructed physicians that chlorpyrifos was a cholinesterase inhibitor.

However, lawsuits may argue that warnings focused on immediate poisoning did not adequately inform farmers and agricultural employees that repeated exposure could contribute to Parkinson’s disease many years later.

The claims do not allege that everyone exposed to Lorsban will develop Parkinson’s disease. Each lawsuit requires an individual review of the diagnosis, work history, duration and frequency of exposure and evidence identifying the pesticide involved.

Evidence for a Lorsban Lawsuit

Many farmers and agricultural workers handled Lorsban years or decades ago and no longer possess the original container or purchase receipt.

That does not necessarily prevent a claim from being investigated. Commercial pesticide use often generated records with the farm, agricultural cooperative, chemical supplier or custom application company.

Evidence that may help establish Lorsban exposure includes:

• Agricultural cooperative invoices
• Pesticide purchase receipts
• Spray and application logs
• Commercial applicator records
• Crop-management plans
• Applicator licenses
• Employment and payroll records
• Farm purchasing and tax documents
• Equipment maintenance records
• Photographs of barns, sprayers or chemical containers
• Statements from coworkers and family members
• Records identifying crops and insects treated

The crops, years and application equipment involved may also provide important clues. Records showing repeated treatment of corn, cotton, citrus, fruit trees or nut orchards during years when Lorsban was widely used may help identify likely suppliers and formulations.

An original receipt or container is not required before speaking with a lawyer. Product identification may be developed through supplier records, crop histories, employment information and statements from people familiar with the agricultural operation.

Contact a Lorsban Parkinson’s Disease Lawyer

The Parkinson’s disease lawyers Saiontz & Kirk is reviewing Lorsban lawsuits for farmers, pesticide applicators, agricultural workers and others diagnosed with Parkinson’s disease after repeated exposure to the chlorpyrifos-based insecticide.

Our lawyers will review the individual’s work history, crops treated, job duties, application methods, potential exposure to Lorsban products and medical records. It is not necessary to remember the exact formulation used or locate old pesticide containers before requesting a free claim review.

There are no upfront legal fees or expenses. Claims are handled on a contingency fee basis, which means Saiontz & Kirk receives no attorney fee or reimbursement of expenses unless compensation is obtained.

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