Chlorpyrifos Pesticide Attorney in Oklahoma City, OK
In 1965, the Dow Chemical Company began production on an organophosphate based pesticide/insecticide with the brand name of Lorsban, a product which quickly became one of the leading chemicals applied to agricultural growth across the United States. The active ingredient in the Lorsban pesticide is Chlorpyrifos. Chlorpyrifos has been used on crops, animals, in buildings, and in other settings to kill several pests, including insects and worms. It acts on the nervous systems of insects by disrupting the function of an enzyme that is also critical to the operation of the human nervous system. Due to the widespread use of this pesticide, the general population has been greatly affected by long term exposure to a chemical that is designed to eliminate insect presence by interrupting processes important to neurotransmission in humans.
While speculation over the safety of this chemical has circulated beginning in the early 2000s, more recent studies have linked long term exposure to severe neurological injuries. A 2025 study from the Neurology Department of the University of California in Los Angeles (UCLA) established that individuals exposed to Lorsban had a 2.5 times greater risk of contracting Parkinson’s disease than individuals who did not have direct exposure to the pesticide. This product has been linked to many other neurological deficits and proven especially harmful to children. Companies that manufacture this substance may have been complicit in failing to adequately inform the public about the dangers of long-term exposure to their product.
The potential Defendants in this case are the various companies that manufactured the Chlorpyrifos containing pesticides. The main claim against these Defendants alleges that due to its danger to exposed humans, there was a design defect in the chemical, or that it was not safely designed for its intended use.
Pesticide Brands Containing Chlorpyrifos:
Chlorpyrifos is sold under a variety of brands. The most common names Chlorpyrifos products are sold under include:
- Lorsban (e.g., Lorsban Advanced, Lorsban 50W, Lorsban 75WG)
- Dursban (frequently used for professional and residential termite/bug control)
- Warhawk
- Pilot
- Cobalt
- Hatchet
- Govern (also called Govern 4E)
- Pyrinex
- Vulcan
- Quali-Pro Chlorpyrifos
- Nufos
The Effect of Parkinson’s in the United States
In 2025, Dr. Jeff Bronstein from the Department of Neurology of UCLA conducted a study focusing on the increased presence of Parkinson’s disease in individuals exposed to Lorsban. The study observed 829 individuals with a formal Parkinson’s diagnosis as well as 824 individuals without the disease. The researchers concluded that individuals with exposure to Lorsban were 2.5 times more likely to have a Parkinson’s diagnosis than those who had no exposure to the chemical.
The Michael J. Fox Foundation states that the average individual who is diagnosed with Parkinson’s disease spends an estimated $26,400 a year on healthcare. This leads to an annual economic burden of 19.8 to 26.4 billion dollars in the United States, affecting both individual citizens and the general population.
Regulatory History of Chlorpyrifos
- 1965 – The Dow Chemical Company introduces Chlorpyrifos, which quickly becomes one of the mostly widely utilized pesticides in the United States.
- 2000 – Under pressure from health advocates, manufacturers eradicate the majority of residential and household use of the Chlorpyrifos pesticide.
- 2007 – The Pesticide Action Network and Natural Resources Council petition the Environmental Protection Agency to ban all food uses of Chlorpyrifos, citing evidence of neurodevelopment harm.
- 2015-2016 – The Environmental Protection Agency states that Chlorpyrifos use on food crops and water sources are unsafe and proposes a ban.
- 2017– The United States Government blocks the proposed ban, preventing further nationwide regulation on the pesticide.
- 2019-2020 – Multiple states, including California, New York, Maryland, and Oregon, begin regulating the Chlorpyrifos chemical on a state level.
- 2021 – The Environmental Protection Agency issues a final rule revoking all usage of Chlorpyrifos on food products.
- 2023 – The United States Court of Appeals for the Eighth Circuit vacates the Environmental Protection Agency’s ban.
- 2024-Present – The Environmental Protection Agency proposed a new ban for all food products, with 11 exceptions.
Who is Eligible to Participate in Potential Litigation for Chlorpyrifos Exposure?
The widespread application of Lorsban has endangered the general population of the United States and proves to be extremely hazardous to those exposed. Chlorpyrifos is easily transmitted to the public through many avenues. Particles of the pesticide can be inhaled by agricultural workers during spraying; the particles can travel through the air into nearby towns and neighborhoods; the produce treated with the pesticide can have remaining traces of the chemical; and it can easily contaminate nearby water sources which are used for drinking water. Long term exposure to Chlorpyrifos can lead to many severe neurological injuries and is especially detrimental to children with developing brains. While this issue poses a threat to the entire population, agricultural employees and pesticide applicators who have spent many hours mixing and applying pesticide, often without the necessary protective equipment, and children who were exposed to Chlorpyrifos or lived in agricultural communities when still in utero or during early childhood and now suffer from neurological deficits.
Recoveries from this lawsuit can include remittance of the cost of medical care, lost income, future
damages for ongoing healthcare, and compensation for ongoing pain, emotional stress, and
permanent injury. If you or a family member have been exposed to Lorsban or another Chlorpyrifos
containing pesticide, and have been diagnosed with a neurological injury, specifically Parkinson’s
disease, call our office for a free consultation to determine if you are eligible for financial recovery.
About the author: Dr. Tara Tabatabaie
Founding Attorney at Fulmer Sill
This page was authored by Dr. Tara Tabatabaie, an attorney and scientist with Fulmer Sill. Dr. Tabatabaie holds a PhD in Chemistry from the University of Oklahoma and a Juris Doctor, Magna Cum Laude, from Oklahoma City University. Prior to practicing law, she served as a senior research scientist at the Oklahoma Medical Research Foundation, studying the biomedical mechanisms behind cancer, neurological disease, and environmental toxin exposure.
Dr. Tabatabaie has served on the Plaintiffs’ Steering Committee and Science Committee in several national multidistrict litigations against pharmaceutical and chemical manufacturers, including In re: Roundup Products Liability Litigation (MDL 2741) against Monsanto and Bayer. Her scientific background has been central to developing the causation evidence and expert testimony behind successful claims against agrochemical companies.
