After recognizing the harmful effects of smoking on health, several items of anti-smoking legislation were enacted. The later 1930s increasingly saw anti-tobacco laws implemented by the Nazis. In 1938, the Luftwaffe and the Reichspost imposed a ban on smoking. Smoking was also banned not only in health care institutions but also in several public offices and in rest homes. Midwives were restricted from smoking while on duty. In 1939, the Nazi Party outlawed smoking in all of its offices' premises, and Heinrich Himmler, the then chief of the Schutzstaffel (SS), restricted police personnel and SS officers from smoking while they were on duty. Smoking was also outlawed in schools.