Hopefully everyone knows that chlorpyrifos (Lorsban and several generic products) tolerances on all food crops were lost on February 28, 2022. This makes ANY application on February 28 or later to a food crop illegal (even though the label on the jug has not changed, nor has the label been revoked).

What happens if chlorpyrifos is found on your vegetable crop?

Enforcement of the zero tolerance will take place in two stages.

Stage 1: EPA will assume any detection of chlorpyrifos below the prior tolerance is the result of a legal application (application according to the label and applied prior to February 28) until the “showing date”. The showing date refers to the date after which any residue of chlorpyrifos will require proof that it is the result of a legal application. Personally, I would make sure I have records to show any application was legal, just in case. If you have proof and don’t need it – no harm done. If you need proof and don’t have it, the crop is considered adulterated. EPA can also request proof of a legal application if they have reason to believe any residue is the result of an illegal application.

Stage 2: if a residue at “previously legal” levels is detected after the showing date, you will be requested to provide proof that the residue is a result of a legal application (application prior to February 28, 2022).

The earliest showing date is currently (the dates can change) September 1, 2022. Fresh market vegetables (treated prior to February 28) are not likely to run into any issues as they should be gone prior to the showing date. Vegetables we store for extended periods (e.g. onions) generally have a later showing date (e.g. onions is March 1, 2023) and also should not run into issues with any legal applications. Processed foods, and particularly frozen foods, are a concern as chlorpyrifos residues are much more stable under those conditions. Thus, if your produce is going into processing, keep records of your legal use of chlorpyrifos.

The Guidance Document, which includes the showing dates can be found at:


We are still lacking on any guidance on how to dispose of unused chlorpyrifos.

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