Have you ever seen one of these high powered rechargable batteries shorted? they can sometimes pop and hiss and smoke and can get hot enough to melt plastic.
They have safty vents but they have to reach a pretty high temp before they do.
Canon has released a safety notice on the A530 and A540 cameras.
If you have one of these cameras, visit this link:
Not all cameras are affected.
If your camera has the fault......Canon will fix the problem...free of charge...regardless of the warranty status.