California Phases Out Paraquat Herbicide Amid Safety Concerns

Paraquat has never been a subtle name. It sits on a pesticide label like a warning from the chemical era: short, sharp, difficult to misread. For California farms, that name is now headed out of the state’s production toolbox.

The California Department of Pesticide Regulation says the phase-out takes effect August 10, 2026, after manufacturers voluntarily canceled their California registrations. The Western Growers Association’s account of the decision describes the change as a statewide loss of a herbicide used in crop production.

A familiar herbicide leaves the shed

Paraquat-dichloride is used for weed control, which puts the change close to the ground in the most literal sense. It touches the spaces between rows, the margins around permanent crops, and the scheduling decisions that determine how a field is cleaned up before the next operation.

The safety concerns behind the decision are health-related rather than tied to a single crop or county. Reporting by the Modesto Bee cites potential links between exposure and thyroid issues and birth defects in humans.

The change comes through voluntary cancellation by every manufacturer of paraquat products registered in California. That matters because there is no single company left to preserve a product line or negotiate a narrow exception; the state market is losing the products together.

Replacement chemistry is not a plug-in part

For a specialty-crop operation, replacing an herbicide is less like swapping one socket wrench for another than rebuilding a small part of the season. A substitute has to fit the crop, the weeds, the application window, the equipment, and the product label. It also has to fit the farm’s labor and water schedule, which are rarely sitting around waiting for a regulatory plot twist.

The Department of Pesticide Regulation announcement establishes the cancellation and effective date, but the available announcement does not identify a universal replacement program for California growers. Alternatives will therefore be a farm- and crop-specific question rather than a single statewide substitution.

That leaves the practical work with individual operations and their advisers: determine where paraquat was part of a weed-control plan, check which registered products can legally fill that role, and account for any changes in timing or field access. The right answer in an almond orchard may not be the right answer in a Salinas Valley vegetable field.