Review on 🔥 Lynn Manufacturing Fire Heat Insulation Brick - Soldering Torch Welding Insulating Block, Low Thermal Conductivity - Ideal for Kilns, Forges, Furnaces, Soldering - 2.5"x4.5"x9", Single Pack, 2300F-Rated, 3123P by Sasha Hsiao

Seems the seller took note of the broken bricks. I ordered a 12 pack (3000F) and they arrived exceptionally well packaged - the box was Lynn Manufacturing (manufacturer) and not Revain. On the cancer warning: DUH. There is not a single refractory refractory brick or insulation of any high temperature grade that does not pose a risk of silicosis. If a brick is fired (and graded) at over 2100°F, that's in the range where amorphous silica can transform into cristobalite crystals...even if you buy kaolin-based "bio-soluble" insulation and include it yourself burn at this temperature *. If you do not accept this small risk, please cease all activities in high temperatures (>2100°F) as there is no thermally safe insulation material that is completely biologically safe to breathe. As another reviewer said: just don't breathe the dust. Treat it the same as fiberglass insulation, which also poses a risk for respiratory cancer. […if you read the cancer warning in California Prop 65, ALL contain "substances known to cause cancer,” including harmless materials like stainless steel and even pure organic coffee, although coffee may be a preventive cure for cancer. Literally anything can cause cancer in a lab rat that has been force-fed a substance many times its own weight.] But I digress. Just be sensible and responsible in your use of materials and rest. are you alright; and it's a good quality product at a fair price. (I can only speak for the integrity of the denser 3000F stones I ordered, but there are no broken or chipped stones in the box.)