OSHA has set guidelines for safe levels of exposure to many airborne contaminants including mists, gases, vapors, dusts, and fibers.  These are known as Permissible Exposure Levels or PELs.  The American Conference of Governmental Industrial Hygienists (ACGIH) has also set guidelines for safe levels of exposure to many contaminants.  These are known as Threshold Limit Values or TLVs.  If a safe exposure level has been identified by OSHA or the ACGIH for a particular material, then it will be provided on the MSDS.
{"Image Tag 0x5110": "1", "Image Tag 0x5111": "0", "Image Tag 0x5112": "0"}