On February 12, 2016, the U.S. Department of Labor’s Occupational Safety and Health Administration (“OSHA”) announced that it plans to issue new guidance as part of its effort to protect workers from the hazards of chemicals. Through May, 2, 2016, OSHA will accept comments on its Guidance on Data Evaluation for Weight of Evidence Determination, which is a companion document to OSHA’s Hazard Classification Guidance for Manufacturers, Importers, and Employers. The guidance will help employers comply with OSHA’s Hazard Communication Standard by instructing employers how to properly evaluate chemical hazards and sufficiently transmit such information concerning their potential hazards to employers and workers.

Under OSHA’s Hazard Communication Standard, chemical manufacturers and importers must evaluate the hazards of the chemicals they produce or import by reviewing all available scientific evidence concerning the physical and health hazards of the chemicals. When a chemical is found to be hazardous, the chemical manufacturer or importer must develop safety data sheets (“SDSs”) and container labels to transmit to downstream users of the chemical. Employers are required to maintain an SDS in the workplace for each hazardous chemical they use. Employers also must develop a written hazard communication program and provide information and training to workers about the hazardous chemicals in their workplace.

The new guidance is intended to help employers consider all available information when classifying hazardous chemicals by instructing companies on how to apply the “weight of evidence” approach when dealing with complex scientific studies. The weight of evidence approach assists manufacturers, importers, and employers in evaluating scientific studies on the potential health hazards of a chemical and determining what information must be disclosed on the label and SDS for compliance with the Hazard Communication Standard. Specifically, it provides a systematic way to evaluate studies that may vary in quality or provide conflicting information, and ultimately help resolve situations where there is contradictory evidence between studies of potentially hazardous materials. Moreover, the weight of the evidence approach makes it possible to pool the results of several less-definitive studies to assist employers in reaching conclusions about hazardous chemicals. Assistant Secretary of Labor for Occupational Safety and Health Dr. David Michaels has noted that “[t]his guidance will help educate chemical manufacturers and importers about OSHA’s expectations on how to prepare accurate safety data sheets and labels required to protect worker safety and health.” The new guidance outlines the types of information to consider in the process of classifying a substance for health hazards, how to evaluate the strength of evidence in classification, the scope and use of the weight of evidence approach, and detailed considerations in the use of the weight of evidence method.

Significantly, the guidance identifies chemical manufacturers and importers as those responsible for conducting hazard assessments and preparing accurate labels and SDSs to protect workers’ safety and health. The guidance also focuses on more complex hazard evaluations, which generally need a higher degree of expert judgment to interpret the studies and provide both technical and logistical advice.

Both employers with extensive exposure to hazardous chemicals and companies with more limited chemical portfolios should consult a team knowledgeable in hazard classification and conducting comprehensive weight of evidence evaluations. This will ensure companies are well prepared to implement the new methods discussed in the upcoming guidance dealing with identifying hazardous chemicals and ultimately help employers comply with OSHA’s Hazard Communication Standard.