I found these 1947 work safety posters via Retronaut. The idea of working somewhere where these are required (and considered adequate for worker protection) is a little disturbing, don't you think?
“These posters were produced at Oak Ridge National Laboratory in 1947. Their purpose was to remind personnel of radiation safety practices and also to let them know what the term “Health Physics” meant, i.e. radiation protection. In 1947 the term was only 4 years old and no less confusing then than now.”
- Oak Ridge Health Physics Historical Instrumentation Museum Collection