Physical Hazards

The physical hazards presented by chemicals often cause harm to workers by exposing them to fire or explosions. Classification of the physical hazards is based on data found in available literature, as a result of a calculation, or through testing using specified test methods. The Hazard Communication Standard does not require the testing of chemicals — only the collection and analysis of currently available data. However, if you choose to test the substance or mixture, then most chapters specify test methods to be used for the given physical hazard.

Selection of Hazard Classes

Once the chemical manufacturer, importer, or classifier has collected the data, the data and test results are compared to the classification criteria. The decision logic included for each physical hazard in this guidance document can be used to identify the appropriate hazard class and category of the chemical. The decision logic is essentially a flowchart for classifying chemicals of the specific hazard. It presents questions in a sequence that considers the classification steps and criteria to classify the hazard in the appropriate hazard class and category. As mentioned throughout this document, many hazardous chemicals have more than one physical hazard and/or health hazard and each hazard must be presented on the label and SDS, as specified in HCS Appendix C, Allocation of Label Elements, and HCS Appendix D, Minimum Information for an SDS. Note that classification of a chemical for one hazard class does not preclude classification of the same chemical for other hazards, unless it is specified otherwise.