I'd go with (a) "safety nut"(s). It's commonly used in American English, and in other countries' English as well. The nuance is similar too :) Examples of "safety nut": 1. It soon became clear that this wouldn't be the case, however, because the person driving the train at that time of night is such a safety nut that he or she lays on that horn long enough to ensure that everyone in three counties hears it at every crossing. Longing for sweet silence by Telegram & Gazette (Worcester, MA) 2. 5 HEALTH and safety nuts in Poole, Dorset, have invented the world's first non-threatening Christmas tree. JACKSON 5 by Sunday Mercury (Birmingham, England) 3. Last week he was on about the health and safety nuts closing down all the schools because of a bit of snow. MUM'S BLAME STORM SESSION by The Mirror (London, England) In a formal setting (academia, professor, etc.) you could say "people in Japan are overly focused on maintaining peace and harmony," but it's a bit long to say.