Legal Standard
40 CFR § 156.62
LD50 (Median Lethal Dose)
Statutory Definition:
The statistically derived single dose of a chemical substance that can be expected to cause death in 50% of a group of treated test animals. Expressed in milligrams of toxicant per kilogram of body weight (mg/kg).
Practical Exam Application:
Lower LD50 values indicate higher acute toxicity. A compound with an oral LD50 of 10 mg/kg is far more lethal than one with an LD50 of 3,000 mg/kg.
Official Practice Exam Questions Testing This Concept (4)
A pesticide container displays the Signal Word 'DANGER' accompanied by a skull and crossbones symbol and the word 'POISON' printed in red. According to 40 CFR § 156.64, what acute toxicity category does this indicate?
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What does the Signal Word 'WARNING' indicate on an EPA-registered pesticide label under 40 CFR § 156.64?
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What acute oral toxicity rating does the Signal Word 'CAUTION' represent under 40 CFR § 156.64?
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Chemical Compound X has an oral LD50 of 15 mg/kg. Chemical Compound Y has an oral LD50 of 4,500 mg/kg. Which product is MORE acutely toxic to mammals?
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