. Author manuscript; available in PMC: 2018 Jul 1.

Published in final edited form as: J Appl Toxicol. 2017 Jan 10;37(7):792–805. doi: 10.1002/jat.3424

Table 1.

GHS potency categories

GHS Category	LLNA EC3	Human Threshold
1A (strong)	≤ 2%	≤ 500 μg/cm² skin area
1B (other than strong –“weak”^a)	> 2%	> 500 μg/cm² skin area
Nonsensitizer	Unclassified	Unclassified

EC3, estimated test substance concentration that produces a stimulation index of 3, the threshold for a substance to be considered a sensitizer in the LLNA; GHS, United Nations Globally Harmonized System of Classification and Labeling; LLNA, murine local lymph node assay.

For simplicity in this paper, we refer to Category 1B sensitizers as “weak”; this term is not used in the GHS.