Hello all competent people!
I'm going to clean the ventilation ducts in my apartment, built in 1947. The duct is located in an inner wall that separates apartments. In the attached picture, you can see all the debris that has accumulated. In the back, you see a gray material. Probably plaster, but I wanted to check with you before I get started. Could it possibly be fiber cement board or some other form of asbestos?
I always err on the side of caution. I'm not planning to tear into the material itself, but I'm thinking there might be disintegrated material in the debris. It's hard to determine, but I appreciate any help
/Jonas