Even the water flowing out of the Thames during the late 1800's wasn't this bad
B4 is located in Arachnid Quarantine Zone space. It has military hyperspace routes leading to Pyong, Constantine, and Diocletian.
History[]
Of the many Bug worlds fought over during the past centuries, many of the battles have been for B4, and it's a place where the Earth Federation has suffered very high casualties.
Geography[]
B4 is a very harsh and unforgiving world. The atmosphere is toxic, and human troopers without highly sophisticated breathing equipment will die within minutes from inhaling even a small amount of the air on this planet. All of the lakes are poisonous. Despite this hostile terrain, the Bugs have no problem operating on the planet.
Season 8 Alternate Timeline[]
In the Middle Kingdom alternate timeline in Season 8, the Bugs were driven off B4, humans colonized the planet, renamed it Julian, and it became the capital of the Western Reserve faction. This was mostly backstory, though, so details like whether the planet was terraformed of if the colonists lived in habitation domes instead was never established.
Behind the Scenes[]
Aside from the obvious (but realistic) lazy-writing tactic of using alphanumerical designations for uncolonized star systems, B4 is a reference to Babylon 4, the predecessor station to Babylon 5.