To measure health norms and assess their influence on behavior among 2541 employees in 16 manufacturing worksites using an adapted Jackson's Return Potential Model (RPM). METHODS: Worksite-level norm intensity, crystallization, and normative power were calculated for several behaviors; linear regression analyses tested whether normative power was related to each health behavior. RESULTS: Norms about safe work practices and smoking were most intense; norms about safe work practices were most crystallized. Safe work practices and smoking held the highest normative power; healthy eating held the least normative power. Comparing norm characteristics across health behaviors leads to important leverage points for intervening to influence norms and improve worker health.