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ZIMSEC O Level Combined Science Notes: Pesticide Warning Symbols

  • Pesticides are graded according to their toxicity i.e.
  • According to how harmful they are to humans.
  • Every pesticide must have a label that clearly shows its “danger” level show.
  • There are four common danger levels of chemicals.

Purple triangle

Extremely poisonous chemical.

Extremely poisonous chemical.

  • For example Methyl bromide used in tobacco seedbed fumigation.
  • Must be handled with extreme care.
  • The poison is extremely lethal,
  • Full protective clothing including gloves, coveralls and goggles, breathing mask must be worn when handling such chemicals.

Red Triangle

Very dangerous

Very dangerous poison

  • Means the poison is very dangerous.
  • Must be handled with care and all the safety precautions must be followed.
  • Should not be used in the home.

Amber Triangle


  • Poisonous pesticide.

Green/Caution Triangle


  • Is less toxic but must still be handled with caution.
  • May be used in the home.
  • For example Killem and other aerosolized sprays.

To access more topics go to the Combined Science Notes page.