Interpreting Toxicity Values found in MSDS

Material Safety Data Sheets commonly include toxicity data in the form of LD50 values. The LD50 (Lethal Dose, 50%) value is typically expressed in mg of material per kg of subject-body-weight, and indicates the quantity of material that, if administered to a population of subjects, will cause 50% of the subjects to perish. The subject animal and the route by which the material was administered should be specified (eg. oral, rat) in order for the LD50 value to be meaningful. That's all well and good, but how do you attach significance to the LD50 numbers that you might find?

Collected here are LD50 values and pointers to MSDSs for a variety of materials. Included are familiar materials ranging from low to moderate toxicity, and a couple of exotic, extremely toxic materials. Remember that a large LD50 means it takes a large quantity of the material to cause a toxic response. Small LD50 values are trouble! These LD50 values (and the associated MSDS sheets) should help you put other LD50 values you encounter into context.