Chlorpyrifos Exposure

Chlorpyrifos is an organophosphate insecticide that affects the nervous system. Acute poisoning has well-known symptoms, while research on long-term effects, especially on children's development, raises different questions. Its federal status has changed several times and still depends on the use. A chlorpyrifos lawyer looks at how, where and when exposure happened and what the rules and science say.

What chlorpyrifos is

Chlorpyrifos is an organophosphate insecticide, first registered in 19651. It works by blocking an enzyme that controls signals between nerve cells, which is how it kills insects and also how it can harm people and animals1. It is an insecticide, not a weed killer.

It is also a different chemical from chlorpyrifos-methyl. EPA closed its review of chlorpyrifos-methyl in 2023 because the last U.S. registrations for it had been canceled2.

How exposure happens

People can be exposed by touching, breathing or swallowing chlorpyrifos1. Exposure can happen to workers who apply it, and to others through contaminated well water, for example when it was used near a well for termite control1. Exposure contexts include:

• Agricultural applicators, mixers and loaders
• Farmworkers re-entering treated fields
• Pest control work
• People living near treated fields
• Well water near past termite treatments

Acute poisoning versus long-term research

Acute poisoning can cause runny nose, tears, drooling, sweating, headache, nausea and dizziness. More serious exposure can cause vomiting, cramps, muscle twitching, weakness and blurred vision, and severe poisoning can lead to unconsciousness, convulsions, trouble breathing and paralysis1. Signs can appear within minutes to hours and last days or weeks1.

Long-term questions are different. Animal studies have linked early-life exposure to effects on brain development, and a study following mothers and children found more developmental delays among children with chlorpyrifos in their blood1. EPA has classified chlorpyrifos as showing evidence of non-carcinogenicity for humans1.

Is chlorpyrifos banned?

Not simply. Its status depends on the use, and it has changed several times:

Federal status of chlorpyrifos food tolerances

1. Feb. 5, 2024

   After a court vacated EPA's earlier revocation of all food tolerances, EPA reinstated the tolerances in its regulations3.

2. Dec. 10, 2024

   EPA proposed revoking all tolerances except those for 11 crops: alfalfa, apple, asparagus, tart cherry, citrus, cotton, peach, soybean, strawberry, sugar beet and spring and winter wheat4.

3. Dec. 12, 2024

   EPA approved registrants' voluntary cancellations and use terminations for certain products, with existing-stocks provisions5.

4. Feb. 20, 2025

   EPA reopened comment on the proposal through March 24, 20256.

As of Nov. 10, 2026, we did not find a final rule on the December 2024 proposal in the Federal Register. States can set their own, stricter rules. We recheck status before advising.

Why chlorpyrifos lawsuits are filed

Claims generally argue that exposure caused acute poisoning or long-term harm and that a manufacturer failed to design or label the product safely7. These claims depend heavily on the specific use, the time period and the state.

Who may have a claim

• The product and where and when it was used
• Your role: applicator, worker, neighbor or other
• Any poisoning event and the medical records from that time
• For children, prenatal and early-life exposure history and developmental records
• The state where exposure happened

Who may be responsible

• Manufacturers of chlorpyrifos products
• Distributors and sellers
• Applicators, in limited circumstances

Filing deadlines for chlorpyrifos claims

Deadlines depend on the state and on when the injury and its cause were discovered. Examples:

• Arizona: generally two years for personal injury and wrongful death8.
• California: two years for personal injury9, and for toxic exposure, two years from the injury or from when the person knew or should have known of the injury and its likely cause, whichever is later10.
• New York: three years, measured from discovery of the injury for the latent effects of exposure to a substance11.
• Texas: two years for personal injury12; the 15-year product limit has an exception for some latent diseases from exposure13.

These examples are not complete, and other rules can apply. A product liability attorney can check the rules for your state early.

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Records that help

Records that can help

Exposure history

• Where you lived and worked, with dates
• Job titles, duties and employers
• Product names or labels, if known
• Spray records or product labels
• Poison center or emergency records

Medical

• Diagnosis date and pathology reports
• Treating doctors and hospitals
• Family medical history, if known

Other

• Water bills or water system notices
• Union, military or training records

What happens after you contact CBW Law

How a chlorpyrifos review works

1. You tell us your history

   Where, when and how exposure happened, and the health effects.

2. We check the regulatory status

   We look at the rules that applied to that use at that time.

3. We review the records

   With your permission, we gather medical and exposure records.

4. We explain what we see

   We tell you plainly whether a claim may be possible and which deadlines apply.

Chlorpyrifos is neither simply banned nor simply allowed. The use, the date and the state decide what the rules were.

Plain English

Medical, Health & Insurance

Terms you may see in a chlorpyrifos case.

Chemical terms

Organophosphate

A class of insecticides that block a key nerve enzyme1.

Tolerance

The legal limit for pesticide residue on food, which EPA sets and can revoke4.

Existing stocks

Product already made that may be sold or used for a time after cancellation5.

Health terms

Cholinesterase

The nerve enzyme organophosphates block.

Developmental delay

When a child reaches milestones later than expected.

Claim terms

Acute exposure

A short, often high exposure with symptoms soon after.

Chronic exposure

Repeated or long-term exposure over time.

Questions

Frequently asked chlorpyrifos questions

Short answers to the questions people ask first.

What is chlorpyrifos?

An organophosphate insecticide first registered in 19651.

Is chlorpyrifos banned in the U.S.?

Not simply. EPA has proposed keeping tolerances for 11 crops and revoking the rest4. Status depends on the use, date and state.

Is chlorpyrifos the same as chlorpyrifos-methyl?

No. Chlorpyrifos-methyl is different, and its last U.S. registrations were canceled2.

What are the symptoms of chlorpyrifos poisoning?

Runny nose, drooling, sweating, nausea and dizziness, and in severe cases convulsions and trouble breathing1.

Does chlorpyrifos cause cancer?

EPA classified it as showing evidence of non-carcinogenicity for humans1. Research has focused on nervous system and developmental effects.

Can a chlorpyrifos lawsuit be brought for a child?

Possibly, depending on the exposure, the developmental records and state law. These are complex cases.

How long do I have to file a chlorpyrifos lawsuit?

It depends on the state and on discovery rules, such as California's for toxic exposure10.

What does a chlorpyrifos attorney at CBW look at first?

How, where and when exposure happened, and the medical records.

How much does it cost to talk to a chlorpyrifos lawyer at CBW?

Telling us your story costs nothing, and contacting us does not create an attorney-client relationship.

Tell Us Your Story

Chlorpyrifos claims turn on the details of the use, the date and the state.

Tell us what happened. CBW Law will review your information and explain what we see. Submitting information does not establish an attorney-client relationship or guarantee representation.

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This page is general information about chlorpyrifos exposure. It is not legal or medical advice and does not create an attorney-client relationship. Exposure, a symptom or a study finding does not, by itself, establish causation or legal responsibility. Regulatory status, laws and deadlines change, and no outcome can be promised. In an emergency, call 911 or Poison Help at 800-222-1222.