E.10.1- Poison counters are poison counters no matter what the source is. [D'Angelo 1998/02/03]
E.10.2- A player loses the game if they have 10 (or more) such counters at the time state-based effects are checked. See Rule T.11. [D'Angelo 1999/05/01]
E.10.3- The "lose if you have 10 poison counters" effect is built into the poison counters. You do not need a poison generating card in play for the rule to take effect. [D'Angelo 1996/10/01]