Dangerous Chemicals

Chemicals designated as Particularly Hazardous Substances (PHS) are dangerous chemicals that are known to have immediate or long term toxic health effects.

The OSHA Laboratory Standard defines Particularly Hazardous Substances as chemicals that are either:

  • Carcinogen
  • Reproductive toxin
  • Highly toxicity on immediate contact

Please develop instructions or a standard operating procedure for the use of these substances in your lab to protect your health and that of others.  Areas where these substances are used must be designated with a sign. These are also OSHA legal requirements:

  • Instructions for use (or a standard operating procedure for use of Particularly Hazardous Substances)
  • Signs (to inform others that dangerous substances are in use in the space)    

The EHS Office has reviewed 160 chemicals commonly in use at MIT and determined whether or not they are Particularly Hazardous Substances.

It should be understood that all of the 160 chemicals on this list are hazardous in some way, yet this list is not all inclusive.  If a chemical you use is not on this list, it does not mean that it is not a Particularly Hazardous Substance.  You must make an informed determination.   A complete description of how to determine whether a chemical is a Particularly Hazardous Substance is in the Chemical Hygiene Plan Template (Part II Section 10).  If you are unsure, please contact EHS Office at (617) 452-3477 or email environment@mit.edu




* Carcinogens according to PHS are chemicals listed by OSHA, the International Agency for Research on Cancer (IARC), and the National Toxicology Program (NTP) as carcinogens.

** Reproductive toxins are chemicals that may adversely affect male and female reproductive health and the developing fetus. One source of information about reproductive toxins is the Proposition 65 list developed by the State of California and updated annually.

*** Chemicals having high acute toxicity are those that have oral, inhalation, or dermal LD 50 s below specified values listed in the OSHA Lab Standard.