GHS and safety
LD50 and LC50
Definition
The dose (LD50) or air or water concentration (LC50) expected to kill half of a test population, used to rank acute toxicity.
LD50 is usually given in milligrams per kilogram of body weight for the oral or dermal route. LC50 is used for inhalation, in mg per litre of air or ppm, and in aquatic tests, in mg per litre of water.
A lower number means higher toxicity. Under the GHS, acute oral toxicity category 1 covers LD50 values up to 5 mg/kg, category 2 above 5 up to 50, category 3 above 50 up to 300 and category 4 above 300 up to 2000 mg/kg. These values appear in section 11 of the SDS.