• It is recommended to use the test data for the complete mixture, if available.
• During hazard determination or hazard classification, account for any hazardous by-products.

Chemical manufacturers and importers evaluating chemical mixtures must follow the procedures described in Appendices A and B to 1910.1200. Under the HazCom standard, it is recommended to use the test data for the complete mixture, if available. If not, then there are other options for classifying the mixture using “bridging principles” based on ingredients and data.

Hazard determination or hazard classification must anticipate the full range of downstream uses of products and account for any hazardous by-products which may be formed. (For example, a manufacturer of gasoline must inform downstream users of the hazards of carbon monoxide, since carbon monoxide is a hazardous chemical and is “known to be present” as a by-product resulting from the use of gasoline.) Also, decomposition products produced during normal conditions of use or in foreseeable emergencies for the product are covered.

Whoever performs the classification is responsible for the accuracy of the information. The evaluation must assess the hazards associated with the chemicals including hazards related to any anticipated or known use or foreseeable emergency which may result in worker exposure. Usually, the chemical manufacturer possesses knowledge of hazardous intermediates, by-products, and decomposition products that can be emitted by their product.