I just started pouring. And after reading some of the posts here i went out and bought one last night from Home Depot. If you go to a store like HD, don't bother asking a worker where they are located, just look for them yourself. I asked two different workers, one in the paint section and one in the tool section, and they both said they don't carry them, only standard dust masks. They were in an odd spot, but they had a whole bay of just respirators and filters.