Precautions with Pesticides:
Read and Follow Pesticide Label Information

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Table of Contents

1. Know the Hazard Symbols and Words
2. Re-Entry Periods
3. Days to Harvest (Preharvest) Intervals, Pre-Grazing and Feeding Intervals
4. Crop Rotation Statements
5. Total Number of Applications
6. Precautions with Pesticide Tables
   • Pesticide Schedules in Ontario (Pesticide Regulations)
   • Safety Supply Companies in Ontario Providing Protective Clothing & Equipment (Table 1-1) (PDF file -18k)
   • Pesticides Act Storage Requirements (Table 1-2)
7. Other topics on Precautions with Pesticides
   • Pesticide Regulations
   • Certification and Training Requirements
   • General Precautions
   • Read and Follow Pesticide Label Information
   • Human Health
   • Protective Clothing and Equipment
   • Protect the Environment
   • Disposal of Pesticides and Empty Pesticide Containers
   • Storing Pesticides
   • Pesticide Spills
   • Application Procedures
8. Related Links

Know the Hazard Symbols and Words

Learn these symbols and words - they could save your life.

Four important symbols and words show the potential hazards of pesticides.

Hazard Symbol	Signal Word
	Poison
	Corrosive
	Flammable
	Explosive

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The hazard symbol will always appear inside one of the shapes shown below.

These shapes and their warning words tell you the degree of hazard of the pesticide. The greater the number of sides to the shape, the more hazardous the product.

Hazard Degree	Warning Symbol	Signal Word
Triangular shape means low hazard (3 sides)		Caution
Diamond shape means moderate hazard (4 sides)		Warning
Octagonal shape means high hazard (8 sides)		Danger

Learn these symbols and words – they could save your life.

Check the label for special warnings about eye hazards and skin hazards. The front panel of the pesticide label may also contain warnings that tell you the product is corrosive to eyes, or is a skin or eye irritant.

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Re-Entry Periods

Re-entry period is the minimum amount of time that must pass between the time pesticide was applied and the time that workers can go into the crop without wearing personal protective equipment. If workers enter treated areas without wearing protective equipment too soon after pesticides have been applied, they may experience poisoning. Such poisoning can result from handling treated plants or from inhaling pesticide vapours.

Some pesticides, like parathion, have labels that carry a warning about working in treated crops. Follow the label recommendations.

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Days to Harvest (Preharvest) Intervals, Pre-Grazing and Feeding Intervals

These intervals state the minimum amount of time that must pass between the last pesticide application and the harvesting of the crop, or the grazing or cutting of the crop for livestock feed. If you harvest a crop before the Pre-Harvest Interval has passed, there may be pesticide residues in excess of the Maximum Residue Limits (MRL) set by Health Canada. When crops with persistent residues are fed to livestock, the pesticides may poison the animal or may contaminate the milk or meat.

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Crop Rotation Statements

Some pesticides can persist in treated soil, and crops sensitive to that pesticide may be injured if they are planted too soon after the treated crop is harvested. Some labels will state a minimum waiting time that must pass before it is safe to plant sensitive crops (See Table 4-3, Herbicide Crop Rotation and Soil pH Restrictions).

Total Number of Applications

Some product labels will state the total number of applications of that pesticide that can be made during a growing season. These limits prevent food residues, crop damage, soil residues or pest resistance.

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Related Links

• Publication 75, Guide to Weed Control
• Publication 812, Field Crop Protection Guide
• PMRA website

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