battery venting

[jackr@internet.kronos.com]

     Ok, the battery relocation threads mention the importance of venting 
     the battery if it's not under the hood (or was it only if it's in the 
     trunk?)  My 100LS had the battery under the rear seat, and I don't 
     recall any special venting about it.  (I haven't had a problem with 
     the V8's battery [yet], so I've never looked at it.)  Are batteries 
     under the seat somehow special?  Does a regular battery there vent 
     dangerous amounts of explosive hydrogen into the passenger 
     compartment?  Enquiring minds want to know.
     
     P.S.  I don't understand why there wouldn't be room under a 4kq's seat 
     for a battery, since an urq is on the same platform and has the 
     battery there.
     
     Jack Rich