Which statement correctly matches hazard class with its oral LD50 range?

• A. Class 1B: 5-50 mg/kg
• B. Class 2: 5-50 mg/kg
• C. Class 3: 50-500 mg/kg
• D. Class 3: Over 500 mg/kg

Answer: (A)

Understanding how hazard classes for acute oral toxicity are assigned using LD50 values helps you see why 5-50 mg/kg fits Class 1B. LD50 is the dose that kills 50% of test animals; the smaller the LD50, the more toxic the substance. For oral exposure, the second-most severe category (Class 1B) covers LD50 values between 5 and 50 mg/kg. That makes this range the correct match for that class.

The other ranges don’t align with the standard thresholds. Higher LD50 values (for example, ranges starting at 50 mg/kg or higher) correspond to less hazardous classes (such as Class 2 or Class 3 in typical schemes). So the statement that best matches the hazard class with its oral LD50 range is that Class 1B corresponds to 5–50 mg/kg.