I work in a rubber manufacturing plant (dairyware, not tyres) and can add more info about carbon black - it gets everywhere and is murder to clean up. I’ve done maintenance on our mixing plant and come away covered in the stuff. First time I’ve ever used a fingernail brush on my face. At our old factory, the carbon black came in paper sacks that leaked/got torn by careless handling. In the new factory the CB comes in giant sacks and is blown into the mixing process using a series of tubes (like the internet!) Much cleaner. The system is provided by Zeppelin Systems (yes, that Zeppelin) - their site is interesting reading if you are interested in rubber.

Great article, David.