How do you dispose electronics? Batteries? Oil? Tires? Cars? Furniture? construction materials? ...
You go to the webpage of your local garbage disposal authority, and read their FAQ, which typically contains where all their disposal centers are, their addresses, opening hours, etc. and what can you dispose on each one.
If what you want to dispose is not listed anywhere, you call them and ask them.
In my country if you want to buy these types of chemicals, you need to ask a company for a price, and the company will ask: who are you? what do you want them for? what's your process for the chemicals? Etc. If you fail to answer any of the questions, they are obligated to report that a "sketchy" party tried to buy some chemicals from them. That might get you a visit from the police, asking even more questions.
That's balancing your freedom to do whatever you want with chemicals with my freedom to enjoy a world that hasn't been polluted by idiots that didn't know what they were doing.