What Is REI (Re-Entry Interval) for Vineyard Pesticides?

By VitiScribe Editorial·November 12, 2025·Updated February 7, 2026

A re-entry interval (REI) is the minimum amount of time workers must stay out of a treated area after a pesticide application. It's a federal worker safety requirement under the EPA's Worker Protection Standard, and it's printed on every pesticide label.

REI violations are among the most common WPS citations in vineyard inspections. They're also among the most avoidable, if you have the right records and processes in place.

TL;DR

REI is the minimum time workers must stay out of a treated area after pesticide application -- it is a federal worker safety requirement under the EPA's Worker Protection Standard, not a food safety requirement; that's PHI
REI and PHI are tracked and enforced separately: PHI is enforced by DPR and state pesticide agencies against food safety standards; REI is enforced by WPS inspection programs and Cal/OSHA against worker exposure standards; both appear on every pesticide label
Failure to post is the most common REI citation in vineyard inspections -- workers must be notified of REIs via posted signs at the treated area and a central location; if you can't produce documentation of posting, you can't prove compliance
REI records must be retained for 2 years under WPS; state agencies including CA DPR, OR ODA, and WA WSDA conduct WPS compliance inspections separately from pesticide use reporting audits -- both can cite REI violations
Workers performing early re-entry tasks during the REI must wear the specific PPE listed on the label for early re-entry; the agricultural employer remains responsible for ensuring no unauthorized re-entry even when a contract spray applicator made the application
VitiScribe auto-records REI alongside each spray log entry, sends push notifications to crew members with block-specific clearance times, and maintains a timestamped record showing workers were notified before any re-entry

REI vs PHI: What's the Difference?

These two intervals often get confused because they both involve waiting periods after pesticide application.

PHI (pre-harvest interval): The waiting period before you can harvest the treated crop
REI (re-entry interval): The waiting period before workers can re-enter the treated area

They're set independently on each product label and enforced under different regulatory frameworks. PHI is a food safety requirement. REI is a worker safety requirement under the Worker Protection Standard (WPS). A product might have a 7-day PHI and a 24-hour REI, or any other combination.

You need to track both. They serve different purposes and are audited by different agencies.

How REI Works in Practice

After a pesticide application, the REI clock starts. During that period, workers cannot enter the treated area for any purpose that could result in contact with pesticide residues, unless they're wearing the correct personal protective equipment (PPE) specified on the label.

For most common fungicides used in vineyards, REIs are 4, 12, or 24 hours. For some restricted-use pesticides, REIs can be 48 hours or longer.

The REI must be posted at the vineyard. Under WPS, you're required to:

Post pesticide application information at a central location workers can access
Keep that information posted throughout the REI
Make the pesticide label and Safety Data Sheet available

In many vineyard operations, this posting requirement is managed with paper signs. It works, but it's easy for posting to be missed or for records to go missing.

VitiScribe auto-posts REI to block records with every spray log entry. No separate paper posting step required. The REI is recorded, timestamped, and available in your compliance history.

For calculating specific REI windows, use the PHI/REI calculator tool. For broader WPS compliance requirements, see the Worker Protection Standard vineyard compliance guide.

Who Must Observe REI After a Vineyard Pesticide Application?

Anyone who would contact pesticide-treated surfaces must stay out of the treated area during the REI. This includes:

Farmworkers: Any agricultural worker who might come into contact with plants, soil, water, or equipment in the treated area
Early entry workers: Workers who must enter during the REI for specific tasks are permitted under limited circumstances with appropriate PPE, but this is tightly regulated

Handlers, which are workers who mix, load, or apply pesticides, have different protections during application but are also subject to REI when they're not actively handling pesticides.

If you use contract spray applicators, they are responsible for completing the application. But you, as the agricultural employer, remain responsible for ensuring that your workers are not exposed to REI violations after the application is complete.

What Records Must You Keep for REI Compliance?

Under WPS, you must maintain records of pesticide applications that include:

Product name and EPA registration number
Active ingredient
Location of the treated area
Date and time of application
Application method
REI for the product used

These records must be retained for two years. State agencies can request them during inspections. California DPR, Oregon ODA, and other state agencies conduct WPS enforcement inspections separately from their pesticide use reporting audits.

A proper spray log entry that includes REI data is your documentation that you managed the interval correctly.

Common REI Violations in Vineyards

Failure to post. The most common citation. Workers must be notified of REIs, typically via posted signs at the treated area and a central location. If you can't produce documentation of posting, you can't prove compliance.

Re-entry during REI without proper PPE. Workers who need to enter a treated area during the REI for urgent tasks must wear the PPE specified on the label for early entry. In practice, this means you need to know what PPE is required before you can authorize early entry.

Inaccurate or missing records. If your spray logs don't include REI information, or if application times are not accurately recorded, you can't verify compliance after the fact.

Misreading multi-crop labels. Some labels have different REIs for different crops. Use the grape-specific REI, not the general entry.

FAQ

What is a re-entry interval for vineyard pesticides?

A re-entry interval (REI) is the minimum time workers must stay out of a treated area after a pesticide application. It's a federal requirement under the EPA's Worker Protection Standard and is listed on every pesticide label. REIs in vineyards typically range from 4-48+ hours depending on the product. The REI must be posted and workers must not enter the treated area until the interval has expired, unless they're wearing the specific PPE required for early re-entry.

Who must observe REI after a vineyard pesticide application?

All agricultural workers who would come into contact with treated surfaces must stay out of the treated area during the REI. This includes farmworkers performing any task in the treated block, such as pruning, suckering, irrigation checks, or any other activity that could result in pesticide exposure. Workers performing early re-entry (entering during the REI for specific tasks) must wear PPE as specified on the pesticide label for that purpose.

What records must I keep for REI compliance in my vineyard?

You must keep spray records that include: the pesticide product name and EPA registration number, active ingredient, treated area location, date and time of application, application method, and the REI for the product used. These records must be retained for two years under WPS. State agencies may request them during inspections separate from pesticide use reporting audits. Digital records that auto-populate REI from label data help ensure accuracy and completeness.

How should overlapping REI windows from multiple applications in adjacent blocks be managed?

When applications are made to adjacent blocks on different days, the REI windows for each block run independently based on the application date and time for that specific block. Workers must track which blocks are under REI and which have cleared. In operations with multiple active REI windows simultaneously, a visual REI status board showing block clearance times is an important field management tool. VitiScribe's block-level REI countdown makes current clearance status accessible from any crew member's phone, showing which blocks are cleared and which remain under REI, so field supervisors don't have to manually calculate clearance times across multiple blocks.

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REI and State Audit Compliance

State pesticide agencies and WPS enforcement agencies can both audit your REI records. California Department of Pesticide Regulation (DPR), Oregon Department of Agriculture (ODA), and Washington State Department of Agriculture (WSDA) all have inspection programs that include WPS compliance checks.

Having complete, accurate spray records with REI data logged for every application is your primary protection in any inspection. Software that automatically records REI alongside each spray log entry, and alerts you to open REI windows, makes compliance far more manageable than manual tracking.

Sources

USDA Environmental Protection Agency (EPA) -- Worker Protection Standard
California Department of Pesticide Regulation (CDPR)
California Division of Occupational Safety and Health (Cal/OSHA)
Oregon Department of Agriculture (ODA)
UC Cooperative Extension Viticulture

Get Started with VitiScribe

REI violations are among the most common WPS citations in vineyard inspections -- and the most common cause is failure to document posting, not failure to post. VitiScribe auto-records REI with every spray log entry, sends block-specific clearance notifications to crew members, and maintains a timestamped notification record. Try VitiScribe free and build complete REI documentation into every spray record today.