How Are MSDS Numbers Assigned?

A materials safety data sheet (MSDS) provides critical information about hazardous substances in the workplace. Information on these documents tells workers how to safely handle hazardous substances and how to avoid being harmed by them.

Definition

• The Occupational Safety and Health Administration (OSHA) requires employers in the United States to have an MSDS for each hazardous chemical at the workplace. The MSDS identifies the hazardous substance and the following information about the hazardous substance:
  1. Physical and chemical characteristics.
  2. Physical hazards.
  3. Health hazards.
  4. Exposure limits (how much of the substance a person can safely be exposed to).
  5. Personal protective equipment.
  6. Emergency and first-aid procedures.

Clarification

• MSDS numbers are not assigned by OSHA. However, standard practice in the United States is to assign a number to the chemical discussed in the MSDS. This is called a Chemical Abstracts Service (CAS) number.

CAS Numbers

• A Chemical Abstracts Service registry number (CAS number) is a number assigned to a chemical. This number is the number typically used to store and retrieve information about the chemical listed in the MSDS.

CAS Number Usefulness

• CAS numbers are useful because often the same chemical has several different names. For example, acetone and dimethyl ketone have different names but are the same chemical substance, so they have the same CAS number.

Responsibility for CAS Numbers

• The American Chemical Society oversees CAS numbers.