The vacuum tube in a CRT can implode if it is broken or punctured. The surrounding air will rush violently into the unsealed vacuum in the CRT, spraying broken glass in every direction. Color CRTs may contain mercury or other potentially toxic materials.
Instructions. Build a hearth for a fireplace that is 16 inches deep, according to This Old House writer Harry Sawyers. This is the standard requirement for municipalities and homeowner associations. The hearth should also extend a minimum of eight inches on either side of the fireplace.
Similar to a gas bar-b-que grill, except for temp. adjustment, your fireplace has a manifold or pipe with small holes in it. With just regular burning, over time soot like particles can become lodged in these opening. Thus cutting down the orifice size considerably. Remove your ceramic logs carefully and do what you can to clear these holes. First use something equal to the diameter of the holes like a thin wire or similar.