I am a horror author and I have a scene coming up in my new book where I need a red-colored gas (or a gas that would somehow be turned or viewed red when viewed from the ground) to be spilled into the atmosphere. Preferably by a tanker truck.
I need this gas to kind of hang over this small community and of course, not kill anyone. Just an eerie red sky. I looked at sulfur hexafluoride, but I think that is colorless and maybe toxic? Looking for something that would make sense here.