Heat Kills is designed to send a simple message. The text is extra-large, for weak eyes, and the colors are designed for maximum, immediate, impact.
The font is chosen for maximum readability in the smaller size, and the pixelation of the larger size should draw an unconscious connection between technology and heat-deaths. The asymmetrical sun-rays in the background are attention-getting yet obviously representational.
No Viridian logo is present, as it would distract from the message and make it obviously political, rather than explicitly health-related. No URL is present because the target audience, of old and poor individuals, is relatively unlikely to have access to the Internet.