biological tolerance values for working materials (Biologische Arbeitsstoff Toleranz Werte (BAT))
The maximum permissible quantity of a chemical compound or its metabolites, or any deviation from the norm of biological parameters induced by those substances in exposed humans.
PAC, 2001, 73, 993 (Risk assessment for occupational exposure to chemicals. A review of current methodology (IUPAC Technical Report)) on page 1022