On 1 August 2023, the South Korea National Institute of Environmental Research (NIER) GHS classification list was updated. The following substances (already classified) had their classifications updated:

1. Dinoseb

2. Bronopol

3. Acrylamide

4. Ethyl chloride

5. 3,3’-Dichlorobenzidine, salts

6. 3,3’-Dichlorobenzidine

7. 3,3'-Dichloro(1,1'-biphenyl)-4,4'-diamine dihydrochloride

The following substances (previously not classified) were assigned new classifications:

1. Cobalt manganese nickel oxide

2. Silica gel reaction products with chromium oxide (CrO3) and ethoxydiethylaluminum

3. 1-Bromo-2-methylbenzene