On 5 May 2023, 9 agents were newly classified by the IARC Monographs:

1. Other cobalt(II) compounds (not including Soluble cobalt(II) salts, Cobalt(II) oxide, Cobalt(II,III) oxide, and Cobalt(II) sulfide)

   Group 3

2. Pentavalent antimony

   Group 3

3. Soluble cobalt(II) salts

   Group 2A

4. Trivalent antimony

   Group 2A

5. Weapons-grade tungsten (with nickel and cobalt) alloy

   Group 2B

6. Cobalt(II) oxide

   Group 2B

7. Cobalt(II,III) oxide

   Group 3

8. Cobalt(II) sulfide

   Group 3

9. Cobalt metal (without tungsten carbide or other metal alloys)

   Group 2A