Do construction workers wearing brightly colored, fluorescent vests catch your eye when driving by a highway construction site? They should. Thanks to Bob Switzer, who invented fluorescent dyes in the 1930s, construction workers, emergency personnel and even joggers are more easily seen during the day. Initially called “Day-Glo” because it “glowed” in daylight, the fluorescent dye played a significant role in saving World War II aircraft crewmen’s lives who wore Day-Glo suits. 
More than 75 years later, the fluorescent dye continues to save countless workers’ lives who wear, what’s now called “high-visibility” or “hi-vis,” apparel on jobsites and mine sites around the world every day as part of their MSHA and OSHA required Personal Protection Equipment (PPE). Cat® Simulators training stresses the importance of wearing high-visibility apparel and PPE on the jobsite.  

Learn more about the evolution of high-visibility apparel: