Question

Highly toxic insecticide, according to WHO classification, are coded as -

• A. Red
• B. Green
• C. Yellow
• D. Blue

Hint:

Toxicity Color Gradient:
Red (Extreme) $\rightarrow$ Yellow (High) $\rightarrow$ Blue (Moderate) $\rightarrow$ Green (Slight).
Remember ROY G BIV backwards, but excluding Orange and Violet.
Red is the most dangerous.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the color coding used to identify "Highly Toxic" pesticides according to standardized toxicological labeling systems (like the WHO or India's CIBRC).

Step 2: Detailed Explanation:

• Toxicity Labeling System:
To ensure safety, pesticides are labeled with color-coded "diamonds" or triangles based on their $LD_{50}$ (lethal dose for $50\%$ of the population).

• Color Codes (Indian Context based on WHO guidelines):
Red (Extremely Toxic): $LD_{50} < 50$ mg/kg. These are the most dangerous and require extreme caution.
Yellow (Highly Toxic): $LD_{50}$ between $51$ and $500$ mg/kg. This corresponds to the "Highly Toxic" category in the question.
Blue (Moderately Toxic): $LD_{50}$ between $501$ and $5000$ mg/kg.
Green (Slightly Toxic): $LD_{50} > 5000$ mg/kg. These are the safest category of agricultural chemicals.

• Signal Words:
Red labels usually carry the word "POISON" with a skull and crossbones.
Yellow labels usually carry the word "POISON."
Blue and Green labels carry words like "DANGER," "CAUTION," or "KEEP OUT OF REACH OF CHILDREN."

• Importance:
This visual coding helps farmers and handlers immediately recognize the risk level without needing to read complex chemical data.

Step 3: Final Answer:
"Highly Toxic" insecticides are coded with the color Yellow.