Thought this might be of interest. According to the OPCW’s page on CW destruction,

Member countries cannot destroy chemical weapons in any way that they like. First of all, the principles and methods for the destruction of chemical weapons have to strictly follow the obligations of the Treaty: para. 12 of Part 4 A of the Verification Annex. On the second hand, the Convention stipulates that the destruction process cannot harm people or the environment.

Now, here are the most relevant portions of the Verification Annex…

Principles and methods for destruction of chemical weapons

12. “Destruction of chemical weapons” means a process by which chemicals are converted in an essentially irreversible way to a form unsuitable for production of chemical weapons, and which in an irreversible manner renders munitions and other devices unusable as such.

13. Each State Party shall determine how it shall destroy chemical weapons, except that the following processes may not be used: dumping in any body of water, land burial or open pit burning. It shall destroy chemical weapons only at specifically designated and appropriately designed and equipped facilities.

14. Each State Party shall ensure that its chemical weapons destruction facilities are constructed and operated in a manner to ensure the destruction of the chemical weapons; and that the destruction process can be verified under the provisions of this Convention.