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Herbert E. Stokinger Award Lecture

Thursday | Noon–1:00 p.m. |

Lectures and Awards

So You Think That You Can … Set Threshold Limit Values?

Presenter: Michelle M. Schaper, PhD, Toxicologist, U.S. Department of Labor, Washington, DC.

Michelle M. Schaper, PhDThe first book of TLVs® was published by ACGIH® in 1961. These TLVs® evolved from a list of approximately 135 Maximum Allowable Concentrations (MACs) of Air Contaminants for 1946. In 1961, there were approximately 250 chemical substances for which TLVs® were developed. They were defined as airborne concentrations that “represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effect.”  Those TLVs® were generally applied to a workforce of normal, healthy, adult males. Today, there are approximately 850 chemical substances for which TLVs® have been developed. Over the years, ‘Notations’ (e.g., SKIN, SEN, A1…5) have been added that remind EHS professionals of special concerns related to a chemical substance. Documentation, which may be extensive, is provided for each chemical substance so that EHS professionals can understand the basis of each TLV®. Although the 2012 definition of the TLVs® still includes the language “nearly all workers may be repeatedly exposed,” today’s workforce is diverse in terms of age, gender, ethnicity, wellness, physical limitations, and other factors. Dr. Schaper’s presentation will review changes in the TLVs® (e.g., numerical values, endpoints of toxicity such as irritation), and in the characteristics of the workers the TLVs® are intended to protect. It is not an easy task to set TLVs® or other occupational exposure limits (OELs). ACGIH® and others who are involved in the development of such limits have been criticized and legally challenged. Dr. Stokinger once wrote about sanity in research and evaluation of environmental health. Perhaps it is time for a reality check on why occupational exposure limits are set in the first place. Our mission has been and remains the protection of workers. Dr. Schaper will discuss the importance of developing, updating, and using current OELs and ensuring that proper training of our workers is being done to fulfill our mission.