9 volt batteries explode! Yuck!

These batteries exploded! Yuck!

Now this is a different experience with batteries I've never had before!
I keep them in a cupboard below my counter between the kitchen and family room. They are stored in a cool and dark place. I was just in that cupboard a few days earlier and never noticed anything odd. This morning I had to grab a phone book out of that cupboard and saw what looked like dried cement inside the bottom of the cupboard door. I keep the batteries on that bottom shelf. I took a closer look at the door and then looked on the bottom shelf and saw these 9 volt batteries askew in their box as you can see in the picture. One battery had the back end complete blown off. There were only three 9 volt batteries in their own package by themselves. I also have AAA, AA, C and D batteries. I checked everything down there. Everything was fine except for these three 9 volt batteries. I cleaned up the mess and threw it away.

I've never had this happen before. I've had toys that had batteries that corroded or flashlights, but never the batteries all by themselves! What I also found odd was that there was 'no expiration date' stamped on the batteries. I bought them from Costco about 2 years ago. Hmmm. Very odd not to have an expiration date.