"Although, the causes of..." or "Although the causes"?

Question

I'm correcting something which my friend wrote. He wrote about incidents that had occurred while working in a mine, and stated that although the cause of each incident may have been different, they had in common a single reason: the workers did not follow the rules.

Here is the sentence:

Although, the causes of each incident may have been different, the same common reason applies:...

I believe that placing a comma after although is incorrect. My friend believes that it is correct. Would you please shed some light on this?

Answer 1

Definitely not ok. In an essay commas ought to be avoided in general [Edit: This is a ridiculous statement. I only meant they are often overused]. Furthermore, "Although," with that comma implies that he's contradicting something he just said. It sounds like he's reinforcing his thesis, so he definitely doesn't want to do that.

Answer 2

Commas are disjunctive and do not suit well with conjunctions. Putting a comma after a conjunction is only acceptable if it is one of a pair of commas bracketing a parenthetical remark:

^OK Although, to be sure, the causes may have been different ...
 ^∗  Although, the causes may have been different ...