Krista Copelan’s home didn’t burn in the Eaton Fire. But for months afterward, it was filled with poisonous traces of things that did.

Arsenic from treated wood and pesticides in the soil. Copper, likely from the wiring systems of the thousands of homes reduced to ash. Lead, discovered on the floor of her daughter’s bedroom, from old paint and leaded gasoline that leached into the ground only to be vaporized by flames.

And on Copelan’s kitchen floor: beryllium.

A little-known earth metal prized for being lighter than aluminum but > more rigid than steel, beryllium is safely used commercially in numerous products, including electronics and cars.

But when heated, objects containing beryllium can release the metal as microscopic particles that infiltrate the lungs. The substance is so dangerous that even a minuscule concentration in air over time — equivalent to a few grains of salt in an Olympic-size swimming pool — can spur development of cancer cells, or a lifelong and sometimes fatal respiratory disease.