Is this a solvent extraction method? If so what solvent is used and if it is organic, do the manufacturers verify elimination of a certain percentage of residual solvent?
Caffeine is mostly extracted by utilizing very safe processes. Some of them, such as Swiss water, is not even really a chemical process.
Please see the following relevant discussions:
- Of the various methods of decaffeinating coffee, which is the safest?
- Which decaffeination process changes the flavor of the coffee the least?
- How is decaffeinated coffee made?
- How are caffeine pills made?
Also, you may want to see this answer to watch an animation of common Swiss water process: