I was an engineer at a company that did production line spray painting. I have never seen a fire or explosion from spray painting but I did witness a fire start from booth filters that had been removed and stacked at break time. The painters returned from their break and found smoke rising from the stack of filters due to spontaneous combustion. Fortunately they arrived early enough to get it put out before any damage was done.
Commercial paint booths are required to have explosion proof lights, switches and motors to prevent any possible problems. While it takes a very specific set of conditions to create an explosion, you DO NOT ever want that to happen! The results are painful and possibly deadly with a strong possibility of fire to make things worse.
Home painting can be done safely with some pretty simple precautions. Eliminate sources of combustion that are close to the painting area and provide some sort of ventilation to remove the fumes.