Associate Safety Professional Practice Exam

What does the LC50 value indicate?

1. The concentration causing death in 50% of animals via ingestion

2. The dosage causing death in 50% via inhalation

3. The amount that can be excreted safely by the body

4. The concentration that is harmless to humans

The correct answer is: The dosage causing death in 50% via inhalation

The LC50 value, or lethal concentration for 50% of the test population, specifically refers to the concentration of a substance in the air that causes death in 50% of a given group of animals via inhalation. This metric is critical in toxicology as it establishes a benchmark for gauging the acute toxicity of airborne substances. The LC50 is typically expressed in terms of concentration (e.g., milligrams per cubic meter) and is utilized to assess the potential risk of exposure to toxic substances in occupational settings, environmental studies, and regulatory assessments. This value is particularly significant as it allows for the comparison of toxicity levels between different substances and can inform safety protocols and exposure limits. Understanding LC50 helps safety professionals in evaluating hazards and implementing appropriate control measures to protect health and safety in workplaces and other environments.