Composition - Information on Ingredients

Section 2 of the standard MSDS contains information concerning the product's individual hazardous chemicals and their relative percentages. Many products contains mixtures of chemicals. All ingredients that meet OSHA Hazard Communication standard criteria of a hazardous chemicals must be identified here. In addition, the materials's corresponding Chemical Abstracts Service (CAS) numbers must also be listed.

The manufacturer has several options as to how the ingredients may be listed. The active ingredients regulated under Federal, state, or local regulations must be listed. The nonhazardous ingredients may or may not be included. Some complex mixtures recognized as a single substance may be listed as a single component. "Trade secrets" are protected and may be listed as such instead of identifying each component. Suppliers of these "trade secret" substances must still provide health hazard data on the MSDS and additional information to safety professionals who have a documentable need to know.

This section should include the material's exposure limits if they are known. Several organizations recognized by OSHA have developed exposure limits for a variety of hazardous substances. Two prominent groups are ACGIH (American Conference of Governmental Industrial Hygienists) and NIOSH (National Institute of Occupational Safety and Health). Its worth noting that the combination of exposures to more than one hazardous chemical is far greater than exposure to individual hazardous chemicals.

Exposure to certain hazardous materials may be acceptable, but only for periods of time not to exceed certain time limits and at concentration no greater than certain levels. This section list these values so the employee handling the hazardous materials knows what precautions, (protective equipment, ventilation, etc) should be taken so as not to exceed these exposure limits. The employee can refer to later sections in the MSDS which describes measures that can help reduce possible exposure.

• Methylene chloride MSDS
Bromine MSDS

If you looked at section 2 of the above MSDS sheets you will have seen that the exposure limits for methylene chloride were not listed. The exposure limits for bromine were very detailed with many values. The OSHA-TWA exposure limit for bromine is 0.1 ppm and the greatest value is 0.3 ppm for the NIOSH-STEL. The Denison University Chemical Hygiene Plan (CHP), Specific Safety Procedures; Toxic Chemicals section states that any hazardous material with an exposure limit less than 50 ppm must be used in a fume hood to prevent against overexposure. The value of 0.1 ppm is far below the CHP value. This should tell you that bromine is an extremely dangerous inhalation hazard and should only be used in a hood.