April 15, 2014

David Cawthon, Ph.D.
Center for Toxicology and Environmental Health, LLC
5120 North Shore Drive
North Little Rock, AR 72118

Dear Dr. Cawthon:

Thank you for your October 14, 2013, letter to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs. Your question concerns classification and labeling requirements under the Hazard Communication standard, 29 CFR 1910.1200, which was revised March 26, 2012 (HCS 2012). This letter constitutes OSHA's interpretation only of the requirements herein, and may not be applicable to any questions not delineated within your original correspondence. Your paraphrased questions and our responses are below.

Question 1: In the HCS 2012, Appendix C, Allocation of Label Elements, C.2.4.8 states, "If the chemical manufacturer, importer or responsible party can demonstrate that a precautionary statement is inappropriate to a specific substance or mixture, the precautionary statement may be omitted from the label." What specifically needs to be done to "demonstrate" a precautionary statement is inappropriate? For example, how would one demonstrate that the precautionary statement, "Store locked up" is not appropriate for a wall board joint compound, which contains crystalline silica, a known carcinogen?

Response: Paragraph (f)(1)(v) of HCS 2012 requires labels of shipped containers of hazardous chemicals to include, among other label elements, the precautionary statements appropriate for the chemical's hazards, as delineated in Appendix C. Under Appendix C.4.9, a chemical that is a carcinogen must include the precautionary statement "Store locked up." In some cases, however, the precautionary statement, "store locked up," may not be appropriate for a particular chemical. If the manufacturer, importer or responsible party can document that the chemical will never present the hazard during storage, but only during use or processing, this precautionary statement may be omitted. If the downstream user has a question about the presence or absence of a precautionary statement, he or she should contact the manufacturer for further information.

The manufacturer, importer or responsible party must have reasonable information, studies or data to support its position that a precautionary statement is inappropriate. The data must meet the criteria in the HCS, Appendix A, Health Hazard Criteria, chapter A.0. It is not acceptable for a manufacturer, importer or responsible party to omit a precautionary statement without data or based only on anecdotal evidence.

Question 2: HCS 2012 Appendix A, Health Hazard Criteria, A.1.3.6.2.3 states, in pertinent part, "Where an ingredient with unknown acute toxicity is used in a mixture at a concentration ≥ 1%, and the mixture is not classified based on testing of the mixture as a whole, a statement that X% of the mixture consists of ingredient(s) of unknown acute toxicity is required on the label and safety data sheet in such cases ..." What specific evidence is necessary to make a determination that a mixture does not need to be classified for acute toxicity when no actual data is available for the ingredients or the mixture as a whole?

Response: When classifying a product, manufacturers, importers or responsible parties must comply with all the information in both Appendices A and B of HCS 2012. Specifically, the classification should start with chapter A.0, General Classification Considerations, as this chapter provides guidance on the appropriate data to use in determining a product's classification. In A.0.2, Available Data, Test Methods and Test Data Quality, A.0.2.3 defines the term "scientifically validated" as it relates to data used in classification. In addition, A.0.2.5 and A.0.2.6 discuss the type of data used and the use of epidemiological data and experience. In A.0.3, Classification Based on Weight of Evidence, A.0.3.2 discusses evaluating the quality and consistency of the data. In A.0.4, Considerations for the Classification of Mixtures, A.0.4.1(c) discusses what to do if testing data is not available for the mixture and the bridging principles cannot be applied: "...the method(s) described in each chapter for estimating the hazards based on the information known will be applied to classify the mixture (e.g., application of cut-off values/concentration limits)." Please note, as stated in A.0.2.1, there is no requirement to test a product.

The approach for classifying mixtures for acute toxicity is tiered, and where the mixture has been tested to determine its acute toxicity, it is classified according to the criteria provided in Table A.1.1. See A.1.3.4. If there is no acute toxicity data for the mixture, A.1.3.5 requires that classification be based on bridging principles. If bridging principles cannot be applied, classification is based on the ingredients of the mixture. See A.1.3.6. If there is no acute toxicity data for the mixture as a whole, bridging principles cannot be applied, and there is no acute toxicity data for the individual ingredients, the mixture does not need to be classified as an acute toxicant and it is not necessary to indicate that there is an ingredient with unknown acute toxicity. As explained in the preamble to HCS 2012, the requirement in A.1.3.6.2.3 to include the percent of the mixture that contains one or more ingredients of unknown acute toxicity only applies where there are other ingredients known to be acutely toxic in the mixture. 77 FR 17574, 17738 ("[W]here there is one or more ingredient of unknown toxicity in a mixture of other ingredients known to be acutely toxic, the calculation for predicting the acute toxicity cannot be completely accurate. Therefore, as suggested in the GHS, OSHA has indicated that a statement must be on the label and SDS indicating that a percentage of the mixture has unknown acute toxicity.").

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA's requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA's interpretation of the requirements discussed. From time to time, letters are affected when the agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA's website at https://www.osha.gov. If you have further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs