Argon is heavier than air. Get your head up! he screams into the cold brain. There is no way to tell how much of the bad air he’s already breathing. Argon is not a poison. There won’t be an allergic reaction, coughing or watering eyes. It is the simplest, most peaceful death conceivable. That’s part of what makes the substance so lethal to handle. If it feels like everything is fine, that’s how you know you’re dying.

