4.3 Directions for Use, REI, PHI & Safety Data Sheets
Key Takeaways
- The Directions for Use section represents a legally binding blueprint under FIFRA Section 12(a)(2)(G), establishing authorized target sites, target pests, dosage rates, timing, and mixing procedures.
- The Restricted-Entry Interval (REI) under the Worker Protection Standard (WPS) prohibits agricultural workers from entering treated fields without specialized PPE; in tank mixes with multiple products, applicators must enforce the longest REI.
- The Pre-Harvest Interval (PHI) specifies the mandatory waiting period between pesticide application and crop harvest, ensuring chemical residues degrade below EPA legal tolerance thresholds on food commodities.
- Proper container disposal requires mandatory triple-rinsing or pressure-rinsing, pouring the rinsate back into the spray tank; open burning of pesticide containers is strictly illegal in Indiana.
- Safety Data Sheets (SDSs) follow OSHA's standardized 16-section GHS format for comprehensive workplace occupational safety, complementing the product label which remains the governing legal instrument for field application under FIFRA.
Last updated: September 2026
4.3 Directions for Use, REI, PHI & Safety Data Sheets
Quick Summary: The Directions for Use section is the operational core of the pesticide label, legally dictating target sites, pests, application rates, mixing sequences (WALES/DALES method), and equipment calibration. In agricultural settings, the Worker Protection Standard (WPS) establishes mandatory Restricted-Entry Intervals (REIs) and field-posting requirements. Food crop applications require strict compliance with Pre-Harvest Intervals (PHIs) to prevent illegal food residues. For occupational safety, employers must maintain standardized 16-Section Safety Data Sheets (SDSs) under OSHA's Hazard Communication Standard, recognizing the critical legal and operational distinctions between the FIFRA Label and the OSHA SDS.
The Directions for Use Section: Legal Mandate & Practical Structure
Under FIFRA Section 12(a)(2)(G), every instruction in the Directions for Use section is legally enforceable. Applying a pesticide to an unapproved site, exceeding the maximum application rate, or ignoring tank-mix restrictions constitutes a federal and state violation.
Key Components of Directions for Use
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┌─────────────────────────┬─────────┴─────────┬─────────────────────────┐
▼ ▼ ▼ ▼
┌───────────────┐ ┌───────────────┐ ┌───────────────┐ ┌───────────────┐
│ Approved Sites│ │ Target Pests │ │ Application │ │ Mixing Order │
│ & Crops │ │ & Timing │ │ Rates/Limits │ │ & Equipment │
│ • Field corn │ │ • Pest growth │ │ • Rate/acre │ │ • WALES method│
│ • Turfgrass │ │ stage │ │ • Max annual │ │ • Agitation │
│ • Greenhouses │ │ • Economic │ │ rate / acre │ │ • Jar test │
│ • Rights-of-way │ threshold │ │ • Gallons/acre│ │ • Chemigation │
└───────────────┘ └───────────────┘ └───────────────┘ └───────────────┘
Core Elements of Directions for Use
- Approved Target Sites and Crops: Specifies the exact plants, animals, soil types, structural areas, or commodities where the product may be legally applied (e.g., "For use on established Kentucky bluegrass and turf-type tall fescue lawns. Do not use on bentgrass or dichondra.").
- Target Pests: Lists the specific insect species, plant pathogens, weeds, or vertebrate pests controlled by the product. Under FIFRA Section 2(ee), an applicator may apply a pesticide against an unlisted pest, provided the application site or crop is explicitly listed on the label.
- Application Rates & Cumulative Limits:
- Single Application Rate: Declared in ounces, pints, quarts, or pounds per acre (or per 1,000 sq ft for turf/ornamentals).
- Maximum Seasonal / Annual Rate: Restricts the total cumulative quantity of active ingredient that can be applied to a single acre per calendar year to prevent soil accumulation, crop phytotoxicity, and environmental leaching.
- Minimum Spray Volume: Specifies carrier volume (e.g., "Apply in a minimum of 15 gallons of water per acre") to ensure adequate coverage.
- Application Timing & Environmental Triggers: Indicates optimal crop growth stages (e.g., "Apply post-emergence when corn is between V2 and V6 stages"), soil moisture conditions, and weather parameters.
- Application Equipment & Restrictions: Authorizes ground boom, aerial, backpack, or chemigation equipment, while explicitly prohibiting unapproved methods (e.g., "Do not apply through any type of irrigation system" or "Do not apply aerially").
The Standardized Tank-Mixing Sequence (The WALES / DALES Method)
When combining multiple pesticide formulations and adjuvants in a spray tank, mixing in the wrong order can cause chemical curdling, phase separation, screen clogging, and sprayer failure. Applicators must follow the WALES (or DALES) mixing sequence unless the label directs otherwise:
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| THE WALES / DALES TANK-MIXING SEQUENCE |
+-----------------------------------------------------------------------------------------+
| 1. W / D: Wettable Powders (WP), Water-Dispersible Granules (WDG), Dry Flowables (DF) |
| (Pre-slurry dry formulations in water before adding to tank with agitation)|
| |
| 2. A: Agitate thoroughly until dry products are completely dispersed in tank. |
| |
| 3. L: Liquid Flowables (F/FL), Suspension Concentrates (SC), Microencapsulated (ME)|
| |
| 4. E: Emulsifiable Concentrates (EC) and oily liquid formulations. |
| |
| 5. S: Surfactants, Adjuvants, Water-Soluble Concentrates (SL), Soluble Powders (SP)|
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[!TIP] The Compatibility Jar Test: Before mixing large volumes of unfamiliar chemical tank mixes, always conduct a physical compatibility test in a clean one-quart glass jar using proportional amounts of carrier, pesticides, and adjuvants to check for precipitation, clumping, or layering.
Agricultural Use Requirements & Worker Protection Standard (WPS)
Commercial agricultural pesticide labels feature a dedicated Agricultural Use Requirements box mandated by the federal Worker Protection Standard (WPS, 40 CFR Part 170).
+=========================================================================================+
| AGRICULTURAL USE REQUIREMENTS |
| Use this product only in accordance with its labeling and with the Worker Protection |
| Standard, 40 CFR Part 170. This Standard contains requirements for the protection of |
| agricultural workers on farms, forests, nurseries, and greenhouses, and handlers of |
| agricultural pesticides. |
| |
| Do not enter or allow worker entry into treated areas during the restricted-entry |
| interval (REI) of 24 HOURS. |
| |
| PPE required for early entry to treated areas that is permitted under the Worker |
| Protection Standard: Coveralls, Chemical-resistant gloves, Shoes plus socks, and |
| Protective eyewear. |
+=========================================================================================+
1. Restricted-Entry Interval (REI)
- Definition: The mandatory time interval immediately following a pesticide application during which agricultural workers are legally barred from entering the treated field, grove, or greenhouse without specialized early-entry PPE.
- Standard REI Durations:
- Category III / IV Products: Typically 12 hours.
- Category II Products: Typically 24 hours.
- Category I Products: Typically 48 hours.
- Arid Region Organophosphate Rule: Labels for certain organophosphate insecticides mandate an extended REI of 72 hours in geographic areas where average annual rainfall is less than 25 inches, because dry, arid conditions slow chemical hydrolysis and degradation.
- The Tank-Mix REI Rule: When an applicator tank-mixes two or more pesticide products with different REIs, the applicator and agricultural employer must enforce the longest REI among all products in the mix.
2. Early-Entry Exceptions under WPS
Agricultural workers may enter a treated area prior to REI expiration only under strict, limited legal exceptions:
- No-Contact Entry: Entry where workers have zero physical contact with treated soil, foliage, water, or greenhouse surfaces (e.g., driving an enclosed tractor cab through a treated field).
- Short-Term Tasks (< 1 Hour): Urgent, short-duration tasks (such as inspecting irrigation equipment) where workers wear full early-entry PPE specified in the Agricultural Use Requirements box, and exposure does not exceed 1 hour per worker per 24-hour period.
- Declared Agricultural Emergencies: Formal emergency declarations by authorized state officials where severe weather or pest conditions threaten total crop destruction.
3. Field Warning Signs & Posting
- Agricultural Posting: Under WPS, when an REI exceeds 48 hours (for outdoor applications) or 4 hours (in enclosed greenhouses), employers must post standardized WPS warning signs at all typical entry points displaying the Spanish/English text: "DANGER PESTICIDES / PELIGRO PESTICIDAS - KEEP OUT / NO ENTRE" along with the stern face and raised stop-hand symbol.
- Non-Agricultural Entry Statements: For non-agricultural applications (turfgrass, golf courses, ornamental landscapes, industrial rights-of-way), the label typically carries a Non-Agricultural Use Requirements box stating: "Do not enter or allow others to enter treated areas until sprays have dried or dusts have settled."
Pre-Harvest Intervals (PHI) & Rotational Crop Restrictions
Pesticide Residue Timeline & PHI
Pesticide Application EPA Chemical Degradation Legal Crop Harvest
Date / Time Window (PHI Met)
│ │ │
▼ ▼ ▼
┌─────────────────┐ ┌───────────────────┐ ┌───────────────────┐
│ Fresh Chemical │ ──────────────────► │ Residues Decline │ ───────────────► │ Residues <= EPA │
│ High Residue │ (Days Elapsed) │ Below Tolerance │ │ Legal Tolerance │
└─────────────────┘ └───────────────────┘ └───────────────────┘
1. Pre-Harvest Interval (PHI)
- Definition: The minimum number of days that must elapse between the final pesticide application and the harvest, cutting, or picking of the agricultural crop.
- Toxicological & Legal Purpose: Established by the EPA to ensure that pesticide residues on raw agricultural commodities degrade to levels at or below the legal residue tolerance established under the Federal Food, Drug, and Cosmetic Act (FFDCA) and 40 CFR Part 180.
- Severe Consequences: Harvesting a crop even one day before the PHI has elapsed violates federal law. The harvested crop is legally classified as adulterated, subjecting the entire commodity to seizure, condemnation, destruction, and substantial financial and civil penalties.
- Pre-Grazing & Pre-Slaughter Intervals: In livestock forage, pasture, or feed crops, labels declare specific waiting intervals before livestock can graze treated pastures or be slaughtered for human consumption.
2. Rotational Crop (Plant-Back) Restrictions
- Many residual herbicides remain active in the soil profile for months or years. The label's Rotational Crop Restrictions table establishes mandatory waiting intervals (e.g., 30 days, 4 months, 10 months, 18 months) before planting specific rotational crops.
- Planting sensitive rotational crops prior to the expiration of the plant-back interval causes severe crop injury, stunted yields, or illegal chemical residues in the rotational crop.
Storage, Container Rinsing & Disposal Mandates
Pesticide container labels contain mandatory legal instructions for chemical storage and environmental disposal.
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| STORAGE & CONTAINER DISPOSAL PROTOCOLS |
+-----------------------------------------------------------------------------------------+
| Storage Security: • Store in original labeled containers only. |
| • Keep in a locked, dry, well-ventilated dedicated room. |
| • Maintain temperatures between 40°F (4°C) and 100°F (38°C). |
| • Prevent freezing of liquid EC formulations (crystal drop). |
| |
| Triple-Rinsing Protocol: 1. Empty remaining pesticide into spray tank; drain 30 seconds. |
| 2. Fill container 1/4 full with clean water. |
| 3. Recap tightly and shake vigorously for 30 seconds. |
| 4. Pour rinsate directly into spray tank; drain 30 seconds. |
| 5. REPEAT steps 2-4 TWO MORE TIMES (total of 3 rinses). |
| |
| Pressure-Rinsing: • Puncture side of container with specialized pressure rinse |
| nozzle; rinse at 40 PSI for at least 30 seconds into tank. |
| |
| Recycling & Disposal: • Puncture bottom/side of rinsed plastic container. |
| • Recycle through the Ag Container Recycling Council (ACRC) |
| program, or dispose in an approved landfill. |
| • NEVER reuse pesticide containers for any other purpose. |
| • OPEN BURNING OF PESTICIDE CONTAINERS IS ILLEGAL IN INDIANA.|
+-----------------------------------------------------------------------------------------+
Safety Data Sheets (SDS) vs. The Pesticide Label
Under OSHA's Hazard Communication Standard (29 CFR 1910.1200), employers must maintain a Safety Data Sheet (SDS) for every hazardous chemical stored or handled in the workplace. SDS documents adhere to the standardized 16-Section Globally Harmonized System (GHS) format.
The 16 Standardized GHS SDS Sections
│
┌────────────────────────────────┼────────────────────────────────┐
▼ ▼ ▼
┌────────────────────────┐ ┌────────────────────────┐ ┌────────────────────────┐
│ General & Hazards │ │ Emergency & Response │ │ Physical & Technical │
│ 1. Identification │ │ 4. First-Aid Measures │ │ 9. Physical/Chemical │
│ 2. Hazard Identification│ │ 5. Fire-Fighting │ │10. Stability/Reactivity│
│ 3. Composition / CAS # │ │ 6. Accidental Release │ │11. Toxicological Info │
│ 8. Exposure / PPE (PEL)│ │ 7. Handling & Storage │ │12-16. Eco, Transport...│
└────────────────────────┘ └────────────────────────┘ └────────────────────────┘
The 16 Standardized SDS Sections
| Section # | Section Title | Key Information & Occupational Scope |
|---|---|---|
| Section 1 | Identification | Product brand name, chemical family, manufacturer details, 24-hour emergency phone numbers. |
| Section 2 | Hazard(s) Identification | GHS classification, GHS signal words (DANGER or WARNING), GHS hazard statements, pictograms, precautionary statements. |
| Section 3 | Composition / Ingredients | Chemical names, common names, exact CAS (Chemical Abstracts Service) registry numbers, confidential trade secret disclosures. |
| Section 4 | First-Aid Measures | Detailed initial emergency medical treatments by exposure route, immediate and delayed symptoms, specific physician notes. |
| Section 5 | Fire-Fighting Measures | Suitable extinguishing media (dry chemical, CO2, foam), specific thermal decomposition toxic hazards, protective bunker gear. |
| Section 6 | Accidental Release Measures | Personal precautions, emergency isolation zones, environmental containment barriers, absorbent materials, cleanup procedures. |
| Section 7 | Handling and Storage | Safe handling practices, ventilation requirements, incompatible chemical storage conditions, temperature limits. |
| Section 8 | Exposure Controls / PPE | OSHA Permissible Exposure Limits (PELs), ACGIH Threshold Limit Values (TLVs), engineering controls, industrial PPE. |
| Section 9 | Physical & Chemical Properties | Appearance, odor, pH, melting/boiling point, flash point, evaporation rate, vapor pressure, relative density, solubility. |
| Section 10 | Stability and Reactivity | Chemical stability, reactivity hazards, incompatible materials, hazardous polymerization, hazardous decomposition products. |
| Section 11 | Toxicological Information | Acute oral/dermal/inhalation toxicity data ($LD_{50}$ / $LC_{50}$), chronic health effects, carcinogenicity lists (IARC, NTP, OSHA). |
| Section 12 | Ecological Information (Non-mandatory OSHA) | Ecotoxicity data for fish, daphnia, algae; environmental persistence, bioaccumulation potential, soil mobility. |
| Section 13 | Disposal Considerations (Non-mandatory OSHA) | Waste characterization, EPA RCRA hazardous waste codes, safe disposal and container recycling practices. |
| Section 14 | Transport Information (Non-mandatory OSHA) | UN number, proper DOT shipping name, transport hazard classes, packing group, marine pollutant status. |
| Section 15 | Regulatory Information (Non-mandatory OSHA) | SARA Title III Tier II reporting thresholds, CERCLA reportable quantities (RQ), TSCA status, state right-to-know laws. |
| Section 16 | Other Information | SDS preparation/revision date, NFPA/HMIS hazard ratings, acronym definitions, literature citations. |
Critical Comparison: Pesticide Label vs. Safety Data Sheet (SDS)
| Feature / Attribute | Pesticide Container Label | Safety Data Sheet (SDS) |
|---|---|---|
| Governing Statute | FIFRA (7 U.S.C. § 136) | OSHA HazCom Standard (29 CFR 1910.1200) |
| Primary Regulatory Agency | U.S. EPA and state lead agency (OISC) | U.S. OSHA |
| Primary Target Audience | Field applicators, agricultural handlers, farmers | Chemical workers, emergency responders, transport drivers |
| Legal Status | Legally binding mandate ("The label is the law") | Occupational safety reference & workplace disclosure |
| Operational Focus | Specific field rates, target pests, crops, REI, PHI | Chemical properties, spill response, industrial exposure (PELs) |
| Signal Words Used | DANGER-POISON, DANGER, WARNING, CAUTION | GHS only: DANGER or WARNING (no CAUTION) |
| PPE Specifications | Specific field task PPE (e.g., nitrile gloves, coveralls) | Broad industrial PPE based on OSHA exposure limits |
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Test Your Knowledge
An agricultural applicator prepares a tank mixture containing three registered pesticides: Herbicide A has a 12-hour REI, Insecticide B has a 24-hour REI, and Fungicide C has a 48-hour REI. What Restricted-Entry Interval (REI) must be enforced for field workers following this application?
A
B
C
D
Test Your Knowledge
What is the primary regulatory purpose of enforcing a pesticide's Pre-Harvest Interval (PHI) on agricultural food crops?
A
B
C
D
Test Your Knowledge
When comparing a pesticide container label with its corresponding Safety Data Sheet (SDS), which statement correctly identifies their distinct regulatory roles?
A
B
C
D