Note when the CEO walks into the finishing room, he has no mask on - while the sprayers do. You'll notice the overspray drifts toward the wall, to go through the exhaust system. One of the reasons that pianos have become expensive is the means of ecological emissions that the companies use. You'll see Bechstein uses a 3 filter system for the exhaust system.
Notes From the Piano Bench
Questions and Answers and updated factoids concerning pianos in the 21st Century.