What Is Paraquat?

What Paraquat Is

Paraquat is a chemical compound used as a herbicide, which is a substance designed to kill unwanted plants. Its full chemical name is paraquat dichloride, and it belongs to a class of chemicals called bipyridyliums. It works by disrupting the process plants use to make energy from sunlight, causing them to dry out and die quickly after contact.

Paraquat is fast-acting and kills a broad range of weeds and grasses, which is part of why it has been popular in commercial farming for decades. It is usually sold as a concentrated liquid that is diluted with water and sprayed. In its commercial form it is often dyed a distinctive blue or green color and given a sharp odor and an added agent that causes vomiting, all of which are safety measures intended to prevent accidental swallowing.

What Paraquat Is Used For

Paraquat is used primarily in agriculture to clear fields of weeds and grasses before planting and to manage growth around established crops. It is commonly associated with crops such as corn, soy, cotton, fruit orchards, and vineyards. Because it kills most green plant tissue on contact, it is also used to dry out or "burn down" vegetation ahead of harvest.

It is not a product sold for ordinary home or garden use. In the United States, paraquat is classified as a restricted-use pesticide, which means it can only be purchased and applied by workers who hold a pesticide applicator license. That restriction is one reason exposure questions tend to center on agricultural and occupational settings rather than consumer use.

Paraquat Products and Brand Names

Paraquat is the active ingredient in a number of herbicide products sold under different brand names. The most widely recognized is Gramoxone, but the same chemical appears in many other products and generic formulations worldwide. For the full list of products and brand names that have contained paraquat, and how to identify which one was used in a past job, see Paraquat Products and Brand Names.

Is Paraquat Banned?

Paraquat is banned or heavily restricted in many parts of the world. It is prohibited in the European Union, the United Kingdom, China, Switzerland, and dozens of other countries, often on the basis of acute toxicity and the difficulty of using it safely.

In the United States, paraquat is not banned. It remains legal as a restricted-use pesticide, and the U.S. Environmental Protection Agency has continued to allow its use with added safety requirements such as mandatory applicator training and closed-system packaging. The gap between how paraquat is treated abroad and how it is treated in the United States is a recurring theme in coverage of the litigation.

Is Paraquat Dangerous to Humans?

Paraquat is acutely toxic to people if it is swallowed, and even small amounts can be fatal. This acute poisoning risk, which usually involves accidental or intentional ingestion, is different from the question at the center of paraquat lawsuits. The litigation concerns long-term, lower-level exposure over years of agricultural work, and whether that kind of repeated exposure is associated with chronic disease.

Keeping those two scenarios separate matters. Acute paraquat poisoning is a medical emergency with immediate, well-documented effects on the lungs and other organs. The lawsuits, by contrast, focus on a possible association between repeated occupational exposure and the later development of Parkinson's disease, which is a slower and more complex scientific question. People researching symptoms should not assume that the two situations are the same.

For a closer look at the symptoms people sometimes research after chemical exposure, see Chemical Exposure Symptoms.

Paraquat and Parkinson's Disease

The reason paraquat is so often discussed in a legal context is the body of research examining whether long-term exposure may be associated with an increased risk of Parkinson's disease, a progressive neurological condition that affects movement. Whether that research amounts to proof is a separate question, covered in Does Paraquat Cause Parkinson's Disease? Plaintiffs in paraquat lawsuits generally allege that manufacturers knew or should have known about this potential risk and did not adequately warn the workers who handled the product.

This is the bridge between the general science of paraquat and the litigation itself. Readers who want the legal side of this topic can continue to Paraquat Parkinson's Lawsuits, which explains the claims, who tends to research them, and what records often matter. The broader category sits alongside Neurological Conditions Linked to Lawsuits and Pesticide Exposure Lawsuits.

Who Makes Paraquat?

Paraquat was first developed in the mid-twentieth century and brought to market in the 1960s under the Gramoxone name by the company now known as Syngenta. Syngenta and Chevron, which distributed paraquat in the United States, are the companies most frequently named in paraquat litigation. Today the chemical is also produced by other manufacturers in generic form, which is part of why it appears under so many product names.