I know they were. But looking back they were severely out of place on Kids' WB!, and after reading in
Beckett's Pokémon Collector that most episodes were heavily edited to match the characters' mouths or eliminate Japanese text — the sorts of things that are anathema to most Japanese animation dubbing practices before and since — that I eventually gave up on the anime until The Pokémon Company took over.
Speaking of which, I remember there being a big to-do over the voice actors retained by 4Kids Entertainment, which dubbed the Pokémon series up to that point, suddenly being put out of work due to contract stipulations. Someone on the big fan forums (probably Bulbagarden, which spearheaded the resulting movement) posted a plea for help that supposedly came from Veronica Taylor, who was the voice of Ash Ketchum, for the community to get them back to work. The terrible initial dubbing job done on
The Mastermind of Mirage Pokémon only exacerbated the controversy, resulting in a shuffling of voice actors and complete redo of the dubbing with Sarah Natochenny as Ash Ketchum. (Natochenny, of course, has still kept the job. Maddie Blaustein, who voiced Meowth but was shuffled out in favour of Jimmy Zoppi, died two years later.)