Ever wonder what’s inside your batteries? Us too! And thanks to CBC, now we know.

For example, did you know that alkaline batteries these days contain little in the way of toxic heavy metals? They actually create energy based on the reaction between zinc and manganese dioxide.

While zinc is essential for a healthy body, too much of it can be harmful by supressing the body’s ability to absorb copper and iron. Inhalation of manganese dioxide can irritate the respiratory tract and may cause metal fume fever, a flu-like illness. Its symptoms include chills, fever, aching muscles, dryness in the mouth and throat, and headache.As well, alkaline batteries have a tendency to leak potassium hydroxide, a caustic agent that can cause respiratory, eye and skin irritations.

But that still doesn’t mean they should be thrown out with your regular trash.