One of the most significant contributions of ACGIH to the field of toxicology is the development of Threshold Limit Values (TLVs). TLVs are guidelines designed to protect workers from the potential health risks associated with exposure to harmful substances. These values represent the level of exposure that the average worker can experience day after day without adverse health effects. TLVs are not regulatory standards but serve as a reference for industries and regulatory bodies to establish safe workplace conditions.