How to Track REI Compliance in the Vineyard

By VitiScribe Editorial·September 10, 2025·Updated October 27, 2025

Restricted entry interval compliance is one of the most operationally difficult parts of vineyard pesticide management. The intervals themselves are easy to look up. The challenge is making sure that every person who might enter a treated block knows about an active REI before they enter, and that the documentation to prove this exists and is organized. Worker Protection Standard violations in this category are common, not because growers are indifferent to worker safety, but because communication systems between spray operators, field supervisors, and other workers break down in ways that are hard to see until an inspector points them out.

What REI Is and Where It Comes From

The restricted entry interval is a federally mandated time period, printed on every pesticide label, during which entry into the treated area is restricted to prevent worker exposure to pesticide residues. The EPA sets REIs based on the toxicity of the active ingredient and the expected residue levels on plant surfaces at the time of potential re-entry.

REIs begin when the pesticide application is complete and the treated area has been vacated by the applicator. They are not set to a clock time; they run from the moment the application ends. A spray that finishes at 9:45 AM with a 12-hour REI means the area is clear at 9:45 PM.

REIs in wine grape spray programs range from 4 hours for many sulfur-based products to 12 hours for the majority of synthetic fungicides applied under WPS to 24, 48, or 72 hours for more hazardous materials. Organophosphate products like chlorpyrifos (where still permitted) carry 72-hour REIs. The REI for each product is on the label and should be recorded in your spray log at the time of application.

WPS Posting Requirements

Under the Worker Protection Standard, the REI, product name, active ingredient, and treated location must be posted at every entry point to the treated area within 24 hours of application and must remain posted until the REI expires. If a block has four road access points, each needs a posting during any active REI.

Central location posting is also required. The WPS central posting location, typically located near decontamination supplies and emergency information, must display application information for all blocks with active REIs. This is the reference point for any worker or supervisor who wants to check whether any areas are currently under restriction.

After the REI expires, the posting must come down. A posting left up after the REI has expired creates confusion and may lead to unnecessary work stoppages. The records showing when the posting was made and when the REI expired should be retained for two years.

Worker Notification Requirements

Before any worker enters a treated area, they must be informed of active REIs for that area. This is not satisfied by posting alone. WPS requires that employees who will be working in or adjacent to treated areas be specifically informed about recent applications and any active REIs. This communication should be documented.

The practical failure mode is the handoff between spray operators and other supervisors. The person running irrigation in the morning may not have seen the spray that happened at 7 PM the night before. The scouting crew arriving at 6 AM may not know about the application that finished at 10 PM with a 12-hour REI. Building a system where spray completion information goes directly to all supervisors with workers in or near vineyard blocks is the operational fix.

Early Entry Exceptions

WPS permits workers to enter a treated area during the REI under specific conditions with appropriate PPE. Early entry work is permitted for tasks that must be performed and cannot wait for the REI to expire. Workers entering during REI must wear the PPE specified on the product label for early entry, which typically includes chemical-resistant gloves, protective eyewear, and a long-sleeved shirt at minimum, and can include more substantial protection for higher-toxicity materials.

Early entry must be for an agricultural task, not for any other purpose. The entry must be documented with the name of the worker, the PPE worn, the duration of entry, and the reason early entry was necessary. This documentation is a WPS record subject to the two-year retention requirement.

Documenting REI Compliance

Your REI compliance documentation should include: the application record showing product, rate, date, time of completion, and the REI duration; records of field posting including what was posted, where, when, and when it was removed; records of worker notification prior to field entry; and records of any early entry with PPE documentation.

Paper documentation works, but it requires discipline to complete at the time of each event rather than reconstructing at the end of the week. Reconstructed records are weaker evidence in a compliance review and more prone to gaps.

VitisScribe logs REI expiration times automatically when spray records are entered, calculates the field clearance time from application end time, and generates a daily status view showing which blocks have active REIs. Field supervisors can check this view on a mobile device before sending crews into any block, eliminating the communication failure that causes most re-entry violations. The system also creates the documentation trail required for WPS compliance review.

Connection to PHI Tracking

REI tracking and PHI tracking are related but separate compliance requirements. Both should be active during pre-harvest planning. A block cleared for harvest based on PHI analysis may still have an active REI from a recent application, meaning picking crews cannot legally enter until the REI expires. Checking both clearances before scheduling harvest crews is the correct procedure.

The overlap between REI and harvest logistics is most acute in the 10 days before a block is expected to reach harvest Brix. During this period, any spray application creates both a PHI clock and an REI clock. Knowing which products have the shortest PHIs and REIs, and timing final applications accordingly, is part of harvest planning.

For complete coverage of pre-harvest interval tracking, see our guide on PHI and REI compliance in the vineyard. For spray record requirements, see vineyard spray record keeping.