Pesticide Safety, Human Health, and Personal Protective Equipment
Exposure routes and toxicity
Pesticides enter the body by dermal (skin), inhalation, oral, and ocular routes. Dermal is the most common route in agriculture; inhalation matters most with fumigants and fine mists. Understand the difference between acute toxicity (short-term, measured by LD50/LC50 and signal word) and chronic toxicity (long-term effects like cancer or reproductive harm). Signal words map to acute hazard: DANGER–POISON (Category I, skull and crossbones), DANGER (I), WARNING (II), CAUTION (III/IV). A low LD50 means high toxicity-a classic trap: smaller number = more toxic.
PPE selection and use
The label's PPE section is the minimum. Know that chemical-resistant gloves must be selected by material (e.g., nitrile vs. butyl) because some solvents pass through certain materials; check the label's chemical-resistance category. Coveralls, aprons, respirators, eye protection, and boots are specified by task (mixing/loading usually requires more than application). Respirators require fit testing, medical evaluation, and cartridge change schedules. Remove PPE before leaving the treated area; wash hands and face; launder work clothing separately.
Traps to watch
- Assuming "CAUTION" means safe-it still requires label PPE.
- Wearing leather or cloth gloves with solvent-based formulations (they absorb and hold pesticide).
- Reusing a respirator cartridge past its service life.
- Confusing the signal word with the PPE requirement; a product can be Category III yet require a respirator.
Worked example
A label says "Category II, WARNING; wear chemical-resistant gloves, coveralls, and a NIOSH-approved respirator when mixing." A worker mixes in a T-shirt with nitrile gloves only-this violates the label even though the product is only "WARNING." Rule of thumb: PPE follows the task and the label, not the signal word alone.