Inmate firefighters are indeed inmate labor, but the issue is whether inmate firefighters are slaves. I don’t think that they are, and I also think that lumping them together with other forms of inmate labor (particularly those that benefit private interests) is misleading and hyperbolic when discussing that point.
White noise. I bought a white noise machine years ago when I lived near a large emergency room that had ambulances going by all day every day. It really helped with the sirens, and when I moved away I kept using the machine. My brain now interprets the white noise as profound silence, and I sleep so deeply that I don’t know how I ever got by without it.