I work at a sandwich shop and we use a bread proofer which is basically just a bunch of humidity and water to help the bread rise. Today I slid the tray out and the whole thing was filled with a black dusty substance. It was a lot. I touched it and tried to clean it with a rag etc. I didn't realize how toxic black mold is until I got home. Can you suffer health risks from just a one time exposure? it was a pretty big sized amount. I was obviously breathing it in while I was scrubbing it. I didn't know if it only posed a risk if it was repeated exposure for example in a house. Thoughts? Thanks.