I called Morehouse Foods (the manufacturer of Atomic Horseradish) and they told me that Smart & Final carries Atomic Horseradish. I would call and confirm with the nearest Smart & Final that they carry it.
Struck out at Milton's. They never heard of it and only carry Beaver. Will call that Stater Bros or Ralph's downtown as mentioned by mcgrath. No luck with the big grocers in my hood in the burbs. Thanks.
I was at the Encinitas Stater Brothers yesterday, and out of curiousity looked to see if they had Atomic Horseradish. I saw that there was one bottle remaining, which I left on the shelf. (I get my hot fix from Phillippe's Hot Mustard.)