Related Rule
South Africa
Practice Relating to Rule 74. Chemical Weapons
South Africa’s LOAC Manual (1996) states: “The use of certain weapons is expressly prohibited by international agreement, treaty or custom (e.g. chemical … and toxic weapons).” 
South Africa, Presentation on the South African Approach to International Humanitarian Law, Appendix A, Chapter 4: International Humanitarian Law (The Law of Armed Conflict), National Defence Force, 1996, § 34(f)(iii).
South Africa’s Revised Civic Education Manual (2004) states:
i. Prohibited Weapons. The following weapons have been prohibited:
(3) Gases Geneva Protocol outlawing their use in 1925. This ban was later strengthened by the adoption of … the Chemical Weapons Convention (1993), which prohibits the development, production, stockpiling and transfer of such weapons. 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 56(f)(i).
South Africa’s Non-Proliferation of Weapons of Mass Destruction Act (1993) provides:
The Minister may, by notice in the Gazette, determine the general policy to be followed with a view to:
(d) the imposition of a prohibition, whether for offensive or defensive purposes, on the development, production, acquisition, stockpiling, maintenance or transit of any weapons of mass destruction. 
South Africa, Non-Proliferation of Weapons of Mass Destruction Act, 1993, Section 2(1)(d).
South Africa’s ICC Act (2002) reproduces the war crimes listed in the 1998 ICC Statute, including in international armed conflicts: “employing asphyxiating, poisonous or other gases, and all analogous liquids, materials or devices”. 
South Africa, ICC Act, 2002, Schedule 1, Part 3, § (b)(xviii).
At the First Conference of States Parties to the Chemical Weapons Convention in 1997, South Africa emphasized the importance of the 1993 Chemical Weapons Convention and stated its commitment to creating a world free of chemical weapons. It reconfirmed its good intentions by once more emphasizing its commitment to global chemical disarmament. 
South Africa, Statement at the First Conference of States Parties to the Chemical Weapons Convention, The Hague, 6–23 May 1997.
According to the Report on the Practice of South Africa, South Africa considers chemical weapons to be among “certain weapons … expressly prohibited by international agreement, treaty or custom”. 
Report on the Practice of South Africa, 1997, Chapter 3.4.