Growing up in Los Alamos, it's not just the lab that adhered to this color standard. Everything that had any vague connection to government, be it the post office, hospital, county council building, public access TV station, and schools were all colored in these various colors. And many things that weren't connected directly still used them, likely because they bought paint as surplus. One of a few elevators in town, part of a small shopping center, was sea foam, as were the lamp posts along downtown streets, and finally, the doors in the Posse Shack were also green, but that's likely because they were directly taken from the lab
Not even just Los Alamos. It was a very common color for schools and hospitals