E-76 is a PC variant of D-76, the film developer; E-72 is a PC variant of D-72/Dektol, the paper developer.
Originally Posted by nspatel
As to toxicity, I'm far from an expert, but my understanding is that sodium sulfite isn't a big risk compared to other chemicals you're likely to have in your darkroom. It's hard for a non-expert to evaluate this, though, since MSDS sheets and whatnot are typically so thorough that they make the most innocuous substance sound like it's a life-threatening toxin. (For instance, check out this MSDS sheet for water.)