The OSHA Lab Safety Standard specifically mandates that labs develop SOPs for handling “Particularly Hazardous Substances”, which they define as Select Carcinogens, Reproductive Toxins and Acute Toxins. If you are unsure if a chemical falls into one of these categories, check the MSDS and the container label. Contact Environmental Health & Safety, (805) 893-4899, if you have questions about the chemicals you intend use.

For Lists or Definitions of Such Materials See:

Select Carcinogens, Reproductive Toxins and Acute Toxins: This is a combined list of carcinogens, reproductive toxins and acute toxins from IARC (International Agency for Research on Cancer), NTP (National Toxicology Program, EPA extremely hazardous substances, Prop 65 (Chemicals Known to the State of California to Cause Cancer or Reproductive Toxicity) in order to reduce redundancy. The combined list is provided as a guide and is not all inclusive. Review material safety data sheet for other materials not listed.


Acutely Hazardous Materials: Substances with a high degree of acute toxicity are those that can cause death, disability, or serious injury after a single, relatively low-level exposure. Pharmaceuticals and biological substances can also present Highly Acute Hazards. The following table denotes the OSHA-defined toxicity designations, for various routes of exposures. Find the LD50 on a material safety data sheet (MSDS) or in the Registry of Toxic Effects of Chemical Substances (RTECS). Compare the LD50/LC50 to the table to determine if it is acutely toxic.


OSHA Hazard Designation Oral LD50 (rats, mg/kg) Skin Contact LD50* (rabbits, mg/kg) Inhalation LC50* (rats, ppm for 1 hr)
Highly toxic < 50 < 200 < 2000 ppm



*. LD50- value is the amount of a solid or liquid material that it takes to kill 50% of test animals (for example, mice or rats) in one dose.
*. LC50- The concentration of the chemical in air that will kill 50% of the test animals exposed to it.