all MSDSs are written to meet the requirements of this new audience effectively.
In summary, among the currently available resources, MSDSs remain the best single source of information for the purpose of evaluating the hazards and assessing the risks of chemical substances. However, laboratory personnel should recognize the limitations of MSDSs as applied to laboratory-scale operations. If MSDSs are not adequate, specific laboratory operating procedures should be available for the specific laboratory manipulations to be employed:
1. The quality of MSDSs produced by different chemical suppliers varies widely. The utility of some MSDSs is compromised by vague and unqualified generalizations and internal inconsistencies.
2. Unique morphology of solid hazardous chemicals may not be addressed in MSDSs; for example, an MSDS for nano-size titanium dioxide may not present the unique toxicity considerations for these ultrafine particulates.
3. MSDSs must describe control measures and precautions for work on a variety of scales, ranging from microscale laboratory experiments to large manufacturing operations. Some procedures outlined in an MSDS may therefore be unnecessary or inappropriate for laboratory-scale work. An unfortunate consequence of this problem is that it tends to breed a lack of confidence in the relevance of the MSDS to laboratory-scale work.
4. Many MSDSs comprehensively list all conceivable health hazards associated with a substance without differentiating which are most significant and which are most likely to actually be encountered. As a result, trained laboratory personnel may not distinguish highly hazardous materials from moderately hazardous and relatively harmless ones.
4.B.3 Globally Harmonized System (GHS) for Hazard Communication
The GHS of Classification and Labeling of Chemicals is an internationally recognized system for hazard classification and communication. (Available at http://www.unece.org.) It was developed with support from the International Labour Organization (ILO), the Organisation for Economic Co-operation and Development, and the United Nations Sub-Committee of Experts on the Transport of Dangerous Goods with the goal of standardizing hazard communication to improve the safety of international trade and commerce. Within the United States, the responsibility for implementing the GHS falls to four agencies: OSHA, the Department of Transportation, the EPA, and the Consumer Product Safety Commission. At the time this book was written, the agencies had not yet provided final guidance on use of GHS. The revised Hazard Communication Standard (29 CFR § 1910.1200) is expected to be issued by OSHA in the near future.
GHS classifies substances by the physical, health, and environmental hazards that they pose, and provides signal words (e.g., Danger), hazard statements (e.g., may cause fire or explosion), and standard pictogram-based labels to indicate the hazards and their severity. When transporting hazardous chemicals, use the pictograms specified in the UN Recommendations on the Transport of Dangerous Goods, Model Regulations. For other purposes, the pictograms in Figure 4.1 should be used. Container labels should have a product identifier with hazardous ingredient disclosure, supplier information, a hazard pictogram, a signal word, a hazard statement, first-aid information, and supplemental information. Three of these elements—the pictograms, signal word, and hazard statements—are standardized under GHS. The signal words, either “Danger” or “Warning,” reflect the severity of hazard posed. Hazard statements are standard phrases that describe the nature of the hazard posed by the material (e.g., heating may cause explosion).