What does the number following LD or LC indicate?

The number following LD (lethal dose) or LC (lethal concentration) specifically indicates the percentage of test subjects that will die when exposed to a specified amount of a toxic substance. It is a critical measure used in toxicology to quantify the toxicity of various chemicals or agents. For example, an LD50 value refers to the dose at which 50% of the test subjects are expected to die, providing a standardized way to compare the lethality of different substances. This concept is crucial for understanding the potential risks associated with chemical exposure in various settings, including firefighting situations where hazardous materials might be involved. It allows responders to gauge the level of risk and make informed decisions regarding safety protocols and personal protective equipment.