Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled? [E0A09]B. Zinc oxideC. Beryllium OxideD. Uranium HexaflourideThe answer is C. Beryllium Oxide. One of the hazards we face as radio enthusiasts is dealing with technology, and quite often the very materials we gain enjoyment from are also toxic if not handled with respect. Beryllium Oxide is one of those. So long as you don’t crush or cut the material, its pretty harmless. The dust is what gets you. I have run into a similar problem in antique radios I restore. Occasionally I will run into a sheet of material acting as a vacuum tube heat shield. You guessed it, its asbestos. I simply remove the piece of material, very carefully, place it into a plastic zipper bag, and put it in the trash, taking great pains not to tear or crumple it. It, too, is harmless if intact, but broken or torn it can release particles that could be inhaled and cause problems.