A lethal dose of a given substance is the dose that is highly likely to cause death. Such doses are established through experiments on animals. Lethal dose is usually given by ingestion or injection. A subscript indicates the portion of the experimental population died from that dose. Lowest published lethal dose.
Lethal concentration is applied only to airborne concentrations.
A lethal concentration of an inhaled substance is the concentration that is highly likely to result in death. Lethal concentration is taken into the body through inhalation of airborne toxic chemicals. A subscript indicates the portion of the experimental population died from that dose. Lowest published lethal concentration. Health effects for different chemicals vary considerably.