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MAC-EQS: 'nd' (Not Derived)
Indicates that no MAC-EQS value could be established — insufficient toxicological data for acute exposure. AA-EQS is the only applicable standard.
When the MAC-EQS is listed as 'nd' (not derived), it means the scientific data was insufficient to derive a reliable maximum allowable concentration value for acute exposure. In this case, the AA-EQS provides the only applicable standard. 'nd' is different from 'na' (not applicable): 'na' means AA-EQS is considered sufficient protection and no acute standard is needed; 'nd' means data was simply lacking. Substances with 'nd' MAC-EQS in Directive (EU) 2026/805: EE2 (No.46), E2 (No.47), E1 (No.59).
Legal reference
Directive 2008/105/EC Annex I, Directive (EU) 2026/805 Annex VI