UPDATE: According to the tweets below, the Reuters story is still considered correct by Reuters; though the story was refuted by Con Edison, Reuters says their source was not @ComfortablySmug and they had photos. A witness listening to the NYFD scanner confirms the story. The Atlantic Wire attributed the story to Comfortably Smug. The CNN story was from Comfortably Smug. (Buzzfeed has screengrabs of his tweets. None they have published mention Con Edison employees trapped.) 

Donald Winslow supports Reuters version of events.

During Sandy, a lot of Twitter was working very hard to curate verified news and alerts to emergencies coming out of the disaster. A lot more of Twitter was having fun trolling with fake photos and fake information. This did not particularly bother most of the news curators, as we know who to believe and who not to, and we've seen most of those pictures before, or ones like them. Tumblr's were set up with debunked photos and reliable Twitter feeds regularly swatted at the trolls.

Some serious and damaging rumours made it onto some of the corporate media who evidently were going for maximum sensationalism vs reliability of accounts. Because of its presence on corporate media which employs professional journalists and fact checkers, and because the sources of information were frequently (usually?) hidden behind such descriptors as 'a Reuters source', the internet was at first unable to validate the authenticity of the source, which proved in many cases to be a well known troll.

While the regular news curators in social media spent the night trying to counter false reports and issuing immediate retractions for any of their own, outlets like Reuters still have uncorrected stories up today.