MAK values (Maximum Concentrations at the Workplace) and BAT values (Biological Tolerance Values) promote the protection of health at the workplace. They are an efficient indicator for the toxic potential of chemical compounds. This book contains a list of scientifically recommended threshold limit values for about 1000 chemical compounds. Carcinogens, germ cell mutagens, embryotoxicants, sensitizing substances and those potentially bearing a risk to pregnancy are treated separately. Of particular value are the lists of substances which were reviewed in the past 12 months, including substances being examined for the establishment of MAK and BAT values in coming years.