https://en.wikipedia.org/wiki/Sunscreen
Among widely used modern sunscreens, one of the earliest was produced in 1944 for the US military by Benjamin Green, an airman and later a pharmacist, as the hazards of sun overexposure became apparent to soldiers in the Pacific tropics at the height of World War II.[22][23][24][25] The product, named Red Vet Pet (for red veterinary petrolatum), had limited effectiveness, working as a physical blocker of ultraviolet radiation. It was a disagreeable red, sticky substance similar to petroleum jelly. Sales boomed when Coppertone improved and commercialized the substance under the Coppertone girl and Bain de Soleil branding in the early 1950s.
And a different source:
http://www.sun-protection-and-products-guide.com/who-invented-sunscreen.html
In the 1940’s a Miami, a Florida Physician named Benjamin Green, invented the first effective sunblock to protect the GI’s in the South Pacific during WWII from sunburn. It was called - Red Vet Pet because it was a red colored petroleum jelly like gel. He later improved on this formula and this new jasmine scented cream became know as Coppertone. In 1944, Coppertone suntan cream was the first commercially mass-produced sunscreen in the United States.
These first products are nothing like what’s available today. They were uncomfortable, pasty, thick and felt like “Paint”.