EM1, I don't think I would have ever gotten rid of the urine. And, cat urine has a horrible smell!!!
I soaked the bricks with some Activated EM1 mixed with water (about 1 cup in a gallon of water). I let it dry to see if that did the trick. It was not 100%, so I did the same thing the next day. There was absolutely no smell after it dried and the cat never peed there again.
Recently we have had a few phone calls about the use of EM1 for pet odors. One person is trying to get the smell out of carpet where her cat urinated. The urine had soaked through the carpet into the floor and sub-floor. The carpet was also stained. Now, if you don't already know, EM1 is brown because it is made with molasses. We instructed her to soak the flooring, let it dry, and see if she needed to reapply.
This seems to have done the trick, but there is still the issue with the stain on the carpet. She washed the carpet with some EM1 and Water (1:20 or 5 ounces per gallon). The stain is being eaten by the microbes in the EM1 and decreasing in size. But, it is still there. Our suggestion was to get a carpet steam cleaner and use EM1 in the water, not the soap/detergent they sell. She is going to add 1/2 cup to the wash water and let us know how it did on the carpet. I plan to report later.