Am I the only person who thinks that Joker may be about to try something?
Yeah–impossible to read the text, but the graphic is clearly:
https://www.interplas.com/product_images/dot-labels/D.O.T.-Non-Flammable-Gas-Label-Transportation-Hazardous-Materials-2-1000px.jpg
I found a picture I took with another camera that I was able to zoom in on. Carbon Dioxide it is.