Forum:Dimension Explosion The 2nd effect of the card

Do both players need to have at least 1 monster removed from the game to activate Dimension Explosion after returning a Fusion monster to the Fusion Deck?

Or does either mean what I think it means.

Which is Dimension Explosion can be used if only 1 player has at least 1 monster in there removed zone. Both players are not required the have monsters removed.