The “green” on boiled eggs shows where they saved you from your own attempts at chemical warfare. Hydrogen sulfide is a toxic gas, flammable and much-feared by miners.

Exactly how long hard-boiled eggs last in the refrigerator. ... adding that overcooked eggs will smell like sulfur, and rotten eggs will smell, well, rotten thanks to hydrogen sulfide ...

You can’t overcook the eggs using my technique, because as soon as the heat is turned off the water starts cooling. Walk away and leave the eggs for an hour, and they won’t be as perfect, but ...