On August 18, 2012 — Adam Dunn becomes the 50th major leaguer to hit 400 career runs when he goes deep in the eighth inning with a two-run blast off Tim Collins in a White Sox loss to Kansas City at Kauffman Stadium. The 32 year-old Chicago first baseman joins Paul Konerko in reaching the milestone this season, making them the first teammates in baseball history to hit their 400th round-tripper in the same year playing for the same team.

Source:
Baseball Reference August 18
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game