Chlorpyrifos is an organophosphate insecticide first registered in the United States in 1965. For decades it was applied across agricultural and non-agricultural settings and sold under dozens of brand names. Many people who were exposed to chlorpyrifos products never knew the chemical was the active ingredient because the brand name on the front of the label rarely said so.
Chlorpyrifos remains under U.S. Environmental Protection Agency (EPA) registration review, and its permitted uses have narrowed. Since July 1, 2025, it may not legally be used in the United States on any crop other than the 11 crops designated by EPA. California has prohibited its possession and use since December 31, 2020.
Wisner Baum continues to investigate and pursue litigation involving chlorpyrifos and a potential association with Parkinson’s Disease. Individuals who were diagnosed with Parkinson’s after verified exposure to chlorpyrifos are encouraged to contact the firm at (310) 207-3233 to discuss whether they may meet eligibility criteria for pursuing legal action.
The brand name of an insecticide rarely indicates the chemical inside it. While federal law requires the active ingredient to be named on the label, it typically appears in small type on the back or side panel rather than on the front of the container.
Chlorpyrifos, for instance, has been the active ingredient in dozens of separately branded products. Brand names also changed over time while the underlying active ingredient stayed the same.
Chlorpyrifos was developed by The Dow Chemical Company, which received EPA registration for it in 1965 and patented it in 1966. Dow Chemical’s agricultural business later operated as Dow AgroSciences. After the 2017 Dow-DuPont merger, the business was spun off as Corteva, Inc. on June 1, 2019.
Today, Dow Inc. and Corteva are separate publicly traded companies, a distinction that matters when identifying which entity is responsible for a given product and time period. Several other registrants later produced and distributed their own chlorpyrifos formulations.
According to Iowa State University Extension, Lorsban and Dursban are two of the most well-known chlorpyrifos-containing products in the United States. Lorsban was labeled for pest control on field and horticultural crops, as well as ornamental plants. Dursban, on the other hand, was primarily used for residential and household purposes prior to its phaseout decades ago.
Both originated with Dow and were later held by Corteva. In February of 2020, Corteva announced that it would end chlorpyrifos production.
The EPA has issued final orders cancelling product registrations for Lorsban (4E, 15G, 50W, 75WG, Advanced), Dursban (4E-N, F, R), Lock-On, Cobalt, and Cobalt Advanced, which means these specific branded products may no longer be used. Indoor and residential uses had been phased out far earlier, under a 2000 agreement with the EPA that ended retail sales by the close of 2001.
The EPA classifies chlorpyrifos agricultural products as restricted-use pesticides, meaning they may only be applied by or under the direct supervision of a certified applicator. That designation covers the agricultural formulations, not the residential products consumers once bought off the shelf, such as Dursban home formulations and containerized ant and roach baits. The EPA eliminated those homeowner uses under the 2000 agreement. California went further, designating chlorpyrifos a restricted material in 2015 and a toxic air contaminant in 2018 before ending its sale in February 2020 and prohibiting possession and use after December 31, 2020.
While Lorsban and Dursban are two of the most widely used name-brand chlorpyrifos products, several others are commonly sold.
According to the USDA grower memorandum and the University of Tennessee, brand names of products containing chlorpyrifos include:
This chlorpyrifos pesticide brands list includes examples of products marketed in the United States by major manufacturers, including Dow Chemical and its successor companies. This list may not contain all formulations sold containing chlorpyrifos. Govern, Hatchet, Whirlwind, and Eraser were Dow-registered trademarks distributed by other companies. As of July 1, 2025, the only chlorpyrifos products that may be used on food crops in the United States — and then only on the 11 retained crops, in the states the EPA specified — are Drexel Chlorpyrifos 15G, 4E-AG, 15GR and 4E-AG2; Drexel Lambdafos; Gharda’s Pilot 4E and Pilot 15G; and Loveland’s Warhawk, Warhawk Clearform, and Match-Up. Every other product named above has been cancelled or has had its food uses terminated.
Chlorpyrifos was also blended with a second active ingredient in numerous products. In those premixes, chlorpyrifos was often not featured prominently on the front of the label. Consumers who are concerned about exposure are encouraged to review chlorpyrifos trade names, including those mixed with other ingredients or classified as premixes.
Trade names of premix and combination products containing chlorpyrifos:
These second ingredients generally fall into a group of insecticides known as pyrethroids and are a separate class from chlorpyrifos. They are sodium channel modulators as opposed to chlorpyrifos, which is an organophosphate insecticide whose mode of action is as an acetylcholinesterase inhibitor.
Chlorpyrifos has had numerous registrants over the years. As noted above, it originated with Dow Chemical, whose agricultural business operated as Dow AgroSciences and was spun off as Corteva, Inc. in June 2019. Corteva’s chlorpyrifos line included Lorsban, Dursban, Cobalt, Cobalt Advanced, and Lock-On, all of which have since been cancelled.
In February 2020, Corteva announced that it would end chlorpyrifos production, citing declining demand and changing market conditions. Despite this announcement, existing stocks and other registrants remained in circulation.
In addition to Corteva Agrisciences, other companies began registering and distributing their own chlorpyrifos products. These companies include:
In 2024, the United States Department of Agriculture (USDA) provided a memorandum to growers about which chlorpyrifos products were still registered for food uses. These products included Gharda’s Pilot, Drexel, and Loveland’s Warhawk and Match-Up formulations.
As of July 1, 2025, chlorpyrifos may not be used on any U.S. crop other than the 11 listed below, and only in states designated by the EPA:
Chlorpyrifos insecticides have been applied in a wide range of places, including in agricultural and non-agricultural areas. According to the California Department of Pesticide Regulation (CDPR), chlorpyrifos products have been used to control a large variety of pests such as aphids, armyworms, billbugs, and chinch bugs.
Historically, and in some cases still where a crop retains its registration, chlorpyrifos products have also been used on:
Residential uses were phased out under the 2000 agreement between the EPA and Dow, with retail sales ending in 2001. A narrow set of non-food uses remains federally registered, including for golf course turf, road medians and industrial sites, utility poles and fence posts, containerized ant and roach baits, and individual fire ant mound treatment, though several states (including California) prohibit chlorpyrifos entirely.
Identifying the brand is an important first step in reconstructing an exposure history because few people remember an active ingredient. What they are more likely to remember is the product in the shed, or the name on the truck that sprayed the field next door. A study published in December 2025 in the journal Molecular Neurodegeneration reported that long-term exposure to chlorpyrifos was associated with more than a 2.5-fold increased risk of developing Parkinson’s disease.
The authors drew on the UCLA Parkinson’s Environment and Genes cohort consisting of 829 Parkinson’s patients and 824 controls in Kern, Fresno, and Tulare Counties. They estimated exposure by geocoding participants’ home and workplace addresses against California’s Pesticide Use Report database rather than by asking them about chemical use. The strongest association they reported was for the longest duration of workplace exposure, with an odds ratio of 2.74 (95% CI 1.55–4.89). The researchers also exposed mice to aerosolized chlorpyrifos and reported dopaminergic neuron loss and other Parkinson’s-like changes, which they described as establishing biological plausibility.
Because that study estimated ambient exposure near agricultural applications rather than personal use of a particular product, brand identification does different work in a residential case than in an occupational one. In either setting, an accurate exposure history, including what was applied, where, when, and by whom, can help in determining whether someone may qualify for a chlorpyrifos lawsuit.
Wisner Baum has litigated pesticide and toxic exposure cases for decades, including against Monsanto in the Roundup litigation, and the firm is investigating chlorpyrifos claims on behalf of people nationwide who were exposed and later diagnosed with Parkinson’s disease. Contact us online or call (310) 207-3233. There is no charge to speak with us about what happened.
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