Firefighter Hazmat vs Cop Hazmat

Firefighters use the “Rule of Thumb,” in which they stage upwind far enough away that they can cover the entire scene with their thumb.

Cops use the “Rule of Donut Hole,” in which they back off until they can see the entire scene through their donut hole…

… and if they keep having to brush powdered sugar off their uniform shirt, they move upwind.

This is why firefighters often refer to cops as “blue canaries,” and refer to such things as “copological indicators” when surveying accident scenes…