Yeah, hear it is: http://www.collegian.psu.edu/archive/2001/11/11-07-01tdc/11-07-01dnews-1.asp November 4th, 2001.... I couldn't find the part in which they admitted it was not an OD but simply water intoxication.
Water intoxication (hyponatremia) is very rare, even in people on MDMA. Although it can happen. What happens is that when you drink too much water, your body doesn't process the electrolytes (mostly salt) it needs. This can be prevented by slowing down, and drinking a sports drink (something with lots of salt) as opposed to water.
Actually- I think I was thinking of some other girl (a younger girl) that died from water intoxication whilst rolling. However, I had friends at Penn State back in 2001 and I'm pretty sure I heard of that also.
Oh yeah. It's VERY rare. Most people wouldn't have to worry about that. I really think the main reason it's happened a few times is people hearing they need to drink "LOTS!!!" of water when rolling and take it to an extreme and then what you said happens. I wonder how much water those people drank to have that happen.
Yeah, that was in colorado, some 16 year old girl. It turned up when I did a "water intoxication ecstasy" search.