Last week the back of a SEPTA bus made a starring appearance in a viral photo that was posted on The photo, as you can see, shows one of SEPTA's diesel/electric hybrids emblazoned with "CLEANER EMISSIONS" as it spewed dirty black smoke into the air on Chestnut Street in Center City.

It makes for a funny, ironic contrast, which is why the photo wound up getting emailed around and posted on Facebook, Twitter, etc. - to say nothing of the fact that everybody enjoys making fun of SEPTA. But is the photo for real? And if so, does it indicate that the hybrid program is just, you know, blowing smoke?

It took SEPTA a couple days to get back to me on this question, but this morning I got the lowdown from Andrew Bush from SEPTA Media Relations, who had researched the details of the specific bus in the failblog photo for me.

"There was indeed a problem with that bus. We were alerted to an issue on March 4th and immediately took it out of service. It turned out that the bus had a cracked catalytic converter that was allowing unburned fuel to run through the system. We ran a bunch of diagnostic tests, did some road tests and returned it to service in the next day or so."

But does this mean we can expect to see others among SEPTA's 270 hybrids belching smoke? Bush says it's pretty much "a one-shot deal. We're not aware of any other instances of this - not to say it couldn't happen again, but it's not a chronic problem. If it were an inherent problem with the hybrid-bus technology, it's likely we would have come across it multiple times before."

For now, we'll take SEPTA's word that this was a singular occcurrence that just happened to get documented in a photo. But careful, because people with cameras will be all the more eager to get the next one, and two slip-ups will just make it all the harder to clear the air.