Backfire, I think?

[duke3282]

This morning when I go to start the car (81sc) there is a loud pop and when I look in the rearview I see smoke coming from the engine compartment. After a few choice explatives I pop the lid and take a look. There is a good bit of smoke seemingly coming from everywhere. When I took off the airbox lid and filter there was a good deal of smoke in there and under the pop off valve. This makes me think it was a backfire and my pop off valve did its job saving the airbox from utter destruction. I tried to start it again and it started fine, like nothing had happened. Should I be concerned about this or was it just a freak accident. Any opinions or suggestions would be appreciated.