I have been roasting for a long time. My last company we had 4 roasters in a 5,000 sq ft room. We had a 120 kilo, 60 kilo, 10 kilo and a 2.5 kilo roasters in that room. I had an employee who has since then has written an article about air quality in roasterys. He constantly complained that the air quality was bad. One day when our new owners were coming in to see the roaster he approached me and rattled off some symptoms of carbon monoxide poisoning....literally 10 minutes before they arrived. I had 3 of the roasters running. I sent him to the workers comp doctor. They ran tests and found nothing wrong. My bosses came in and watched me run the roasters like a champ. Next day employee came in smiling saying,"sorry I had to leave..guess it didn't go well after I left" He was disappointed to hear it went great. To make sure everyone was safe we brought in an outside company to test the air quality. They tested for everything they could think of. They found nothing. Someone in the company was not satisfied with the results and called the EPA. The government came in and did their own testing.....they came up with nothing dangerous. We were roasting at that facility for many years after that.