Hazards of Chemicals and Gases
The absence of a substance from the list does not necessarily indicate that a substance is not
toxic. Some hazardous substances may not qualify for the list because the dose that causes the
toxic effect is not known.
Other chemicals associated with skin sensitization and carcinogenicity (ability to cause cancer)
may be omitted from the list, because these effects have not been reproduced in experimental
animals or because the human data is not definitive.
It is not the purpose of the list to quantify the hazard by way of the toxic concentration or dose
that is presented with each of the substances listed. Hazard evaluation involves far more than
the recognition of a toxic substance and a knowledge of its relative toxic potency. It involves
a measurement of the quantity that is available for absorption by the user, the amount of time
that is available for absorption, the frequency with which the exposure occurs, the physical form
of the substances, and the presence of other substances, additives, or contaminants (toxic or
The purpose of the Material Safety Data Sheet (MSDS) is to ensure the individuals working
with chemicals and in the vicinity of chemicals have specific information on these chemicals.
This form identifies the chemical by its technical and common name and lists the
physical/chemical characteristics and fire, explosion, and reactivity hazards. The second page
specifies health hazards and recommends first aid procedures. The safe handling and control
measures are also supplied. The MSDS is a very helpful document, and personnel working
around chemicals should make it a practice to review these sheets frequently for their own
safety. Figures 2 and 3 are copies of the MSDS.
The Code of Federal Regulations recommends that the hazards of all chemicals produced and
imported be evaluated and the information concerning the hazards be transmitted to the
employers and employees. The MSDS, labels on containers, and employee training should be
part of a comprehensive hazards communication program.