I live in an older apartment building with a wall of exposed brick in the living room. Some of the mortar crumbles off the wall pretty easily, and I recently noticed a weird white substance on some of the bricks. I haven't tried touching it because I don't know if it's safe to or not. It looks kind of like a powder, crystalline substance, as if some snow had drifted onto the brick and stuck (except that it's a blazing hot summer right now and the exposed brick is inside my apartment). I have pictures of it, but I can't post them on this thread since this is my first post to the forum. Can someone tell me if this is safe, or if this is something harmful like asbestos???

I don't know if this is relevant or not, but my landlord recently sprayed my apartments for ants since there appeared to have been a recent infestation of ants coming out of the walls and cracks.