Inside Tesla’s electric car factory, giant red robots – some named for X-Men characters – heave car parts in the air, while workers wearing black toil on aluminum car bodies. Forklifts and tuggers zip by on gray-painted floors, differentiated from pedestrian walkways by another shade of gray.

There’s one color, though, that some of Tesla’s former safety experts wanted to see more of: yellow – the traditional hue of caution used to mark hazards.