In the U.S., OSHA requires that MSDS be available to employees for potentially harmful substances handled in the workplace under the "Employee right to know" rules.
An MSDS for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational fashion. For example, an MSDS for a cleaning solution is not highly pertinent to someone who uses a can of the cleaner once a year, but is extremely important to someone who does this in a confined space for 40 hours a week.
External link: MSDS Search page (Cornell University), http://msds.pdc.cornell.edu/msdssrch.asp