If you dream of working blender spewing out contents, its a man-made disaster. You might see your kitchen in a mess. The dream interpretation is that you might see an induced incident. There could be a fault in the electrical blender equipment. Maybe you made a mistake by overfilling the blender beyond its working capacity. When the motor is switched on, the force of the motor might create a big pressure that blew off the top cover of the blender container and thus the spewing out contents. This dream is a kind of warning to you to check your equipment for malfunction, and also to observe safety precautions in operational procedures. This will help prevent man-made incidents like spilling and overflowing or other incidents.
Another dream meaning can be that your secrets are going to get leaked (spewed out). If you face this kind of situation in real life, you might like to consider your next steps to handle this possible situation.